Cells that did not blow the fuse are defective, not able of supplying 2 A into a short. Try one of the cells that did not blow its fuse and see how many amps it will provide into a dead short. (My guess is: almost nothing). Unless You break the fuse glass they are surprising rigid. I have mounted 7000+ of these and I have less than 1% that breaks.
Yes I was thinking the same, clamp the current meter on the bus bar wire to see what current there still is on those cells that did not blow their fuses.
This is where a battery load tester comes into play during the processing stage. The ZTS MBT-1 pulse load tester is what Ive been using for a couple years now. It looks kinda cheap looking for what it costs but its actually really rugged.
Great set of safety videos lately, I think a lot of people appreciate them, thanks! Some fuses didn’t pop so I think the following should be investigated: 1. Are the fuses themselves faulty ( put current over them with your PS and test it). If yes, the fuses themselves or installation method should be questioned. If not... 2. Check if the cells of which the fuses didn’t blow, have peculiar behavior. Heaters, drainers, high internal resistance, low capacity left, ... if this is the case we should try to figure out a method to detect this during initial cell testing so they never end up in a pack. That is of course if the problem is already present from the beginning and not caused during aging of the pack.
Re 1: I have actually come across one faulty fuse. There were 2 fuse wires inside the glass tube together with 2 leads in each end 🙂 , well I discarded that one.
Interesting results! Thanks for this video. Fuses take a different amount of time to blow depending on the current. This can be checked via their “I2T” curves in the datasheet. Those curves show the time versus current before the fuse will blow. Since each battery has a different internal resistance that means each will output a different amount of current when the pack is shorted and each fuse will take a different amount of time to blow. Fuses have a tolerance too, not all will blow at the exact same time for the same current level. Lastly, different lead lengths for each fuse results in different levels of heat being conducted away from the fusing element. This can affect the amount of time it takes to blow the fuse, especially if the current levels aren’t high enough to instantly pop it.
I do follow and watch your videos. What I know with used cells is some have a very high internal resistance (although the capacity and discharge test passed) so the fuse may fail to burn as it should.
it is realy important to have cells with low IR, IR is direcly linked to the health of your cells....there is a guy at second life storage his name is wolf he made a study how IR relates to the health of cells. I have also a 18650 48 volt 150 ah bank and are IR and mah matched my bank are realy balanced 0.003 volt difference
The fuses that did not blow were likely a damaged in hook up or poorly connected, this bears out in the fact that you had to press and move the fuse around to get a decent contact, even this though is a better result as it shows a disconnect in voltage to the bus bar where the previous fuses still had full contact. Thanks for doing these videos as they are a great help to many people.
those non resetable thermal fuses are probably for mounting inside transformers touching the coils, they will blow up when the transformer gets over a certain temperature
For the thermal fuses, it is recommended to use a crimp or spot weld to install them. If you have to solder them you will want to use something like a cold wet rag or even an ice cube around the body and in the connecting wires of the fuse depending on the temperature rating of the fuse to keep them from failing during installation.
I have a power supply just like that. Very handy. I've found that the glass fuses break at roughly twice their current rating. If the fuse wire doesn't break until 8A, I'm not sure what use they would be unless you're using several amps per cell normally. I've also found that a small number of glass fuses are defective in each package I buy. So I check each one before I install it. With practice, they can be made to look nice on a battery.
A few points, if you will. The glass fuse you tested blew at 1.75 A or so, which indicates that it's rated something between 0.5 and 1 A, as others have already stated. Now, if there's any way you could get the pack to an electronics lab, here's how I would test it: hook it up to a DC electronic load. Monitor pack voltage and current with an oscilloscope (you need a shunt resistor or current probe for this). Only connect as many cells in parallel as the current rating of the measurement system allows - you can measure the pack in segments if necessary. Ramp up the current at the electronic load, and monitor the pack with a thermal camera. Try various loads and patterns (like for example a short peak load over a base load) and see what happens. (That's how I test power supplies - only I'm a bit far away...) One possible idea re thermal protection would be to install a thermal sensor between every four cells (so a 40p pack would have 10 sensors). These might be PTC resistors in series, so that any one cell heating up past a certain temperature would cause the entire chain to go high resistance. This in turn would trip a circuit breaker for the whole pack (or have the BMS disconnect it) and trigger an alarm. The way I see it, individual fuses will help in some situations, for example when an individual cell is being dangerously overloaded for any reason that isn't caught by a downstream protection device. However, there are serious failure modes where no fuse does any good, such as an individual cell going high resistance. Also, high internal resistance can be a symptom of something very serious that would warrant immediate disconnection from load - but this is something that a fuse fails to catch. In fact, high enough internal resistance can prevent the cell fuse from blowing at all.
in lieu of a scope i test my batteries with a cheap ZKETCHE EBD-USB Voltage and Current Monitor and can even save the plots on their software program supplied with it.
Would be interesting to see the IR of the cells that didn’t pop the fuse and that did, couple of other people have mentioned this too. Also another test would be to dead short those single cells one at a time with a multiple meter inline to see what amps it is able to sustain during and compare to other cells see if there is a difference
Important is the voltage over the fuse. The fuse wire in the lenght shown the supply shows 1V and the wire only glowing dark. Then you have both cell sides fused so 2v over the fuses to pop them. No margin for higher IR cells there. Fuse on the cells should only have 0.5v drop when breaking
Those 5 fuses that didn't blow might have been on batteries with high internal resistance / batteries that can't deliver the required 2A. I hope that's the case, otherwise the fuses are bad. Damaged fuses would burn out *sooner*, not later. The voltage spiking when you pressed the busbar was probably from your hand conducting from healthy cells to the bus ;)
Some calibration and testing would need to be done but, sensing the resistance of the pack with a custom circuit and tripping a shunt trip breaker for that particular pack when the resistance drops below a threshold (dead short). Don't have a pack to test with, but this method does work on larger industrial battery backup systems. Thanks for the videos btw :) Cheers from Canada
The problem with some/many PSUs is they have an electrolytic on the output so if you set a constant current, limiting does not start until the cap has discharged. The way around this would be to short the output, set the current limit, attach the load and only then remove the short.
Never in a million years, would I have believed that "fuse wire" would carry almost 9A. That's insane! This is why glass fuses are a better alternative. You know what you're getting (within tolerance). Those thermal fuses are of no use to you, unless you intend to strap them to the side of every single cell and even that would be of limited use, seeing as the thermal fuse temp is so high. Their intended use is in appliances with a thermal element or similar (the side of a motor for example) as a fail safe (usually secondary). It really is beginning to look like the only way to make these installations safer, is 1: containment of packs, and 2: a sensor matrix that monitors literally every cell looking for heaters. www.ebay.com.au/itm/50PCS-MF52AT-MF52-MF52B-3950-NTC-Thermistor-Thermal-Resistor-5-10K-50K-100K/193240413757?_trkparms=aid%3D1110009%26algo%3DSPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20201210111452%26meid%3D565190a3b0c943a58f6d352d9ec09b1e%26pid%3D101196%26rk%3D7%26rkt%3D12%26mehot%3Dnone%26sd%3D201415005626%26itm%3D193240413757%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3Ddefault&_trksid=p2047675.c101196.m2219 www.ebay.com.au/itm/10pcs-NTC-Thin-Film-Thermistor-100K-precision-1-MF5B-SMD-for-3D-Printer/201415005626?hash=item2ee54515ba:g:A8cAAOSwBLlVWxJX There must be a cheaper way to procure them in bulk. If people are interested I will start designing some sort of data acquisition/monitor capable of handling 1000's of sensors.
The "fuse wire" can vary, too, depending on the quality of the copper used and/or if it's copper clad aluminum (CCA) (some use networking cable for fuses which some of it is called CCA. This is cheaper networking cable, but the cable is much less flexible). This can be an issue if you've ended up mixing different brands or spools of wire to make the fuse links. This is also why if someone chooses to go this route "they" must test the fusing capability of their wire, not just go off of some YT video and call it good enough.
@@korishan For a very long time (VERY, so long in fact that I've forgotten where I read it. Probably in an EA magazine some time in the 90's) I always was of the belief that a single strand of "Telecom wire" which was solid, single strand copper phone wire used by Telecom, now Telstra, was good for 2-3 amps and relied on that knowledge as a rule of thumb. I have doubted that it would fuse at 3A for some years, but never bothered to test it or any other wire for CSA vs current carrying capability. Having watched that, I'm going to do some research into it. It's not knowledge I've really needed before but now I'm curious to know.
I use 30AWG tinned copper for my fuse wires. I'm of the impression they melt at 12-20a based on my 'loose' tests. I never expected all fuses to blow in a pack short. I expect the minority (e.g. 1 bad cell) fuse to melt/disconnect based on the amps of the other 50 or 100cells. When it gets down to 5 cells left of 100 cells - still connected to the bus because the fuse wires didn't 'blow'... that makes sense to me. The 5 or 4 or 3 cells may not have have amps to melt 30awg at 20a... they just dead-short and run down. BUT I also don't expect these remaining 5 or 4 or 3 cells that can't muster 20a to catch fire. So I'm confused at the notion that all cells would disconnect from the buss at battery short. This is why I also fuse the 'battery' as a whole. Again, there are 2 events here in my mind - the BIG SHORT - which hopefully will trip the battery level fuse and/or most of the fuse wire... but there is a post situation where there could be some power left in the battery - not enough to burn remaining fuse wire. I'm not saying that my understanding is correct - just something I've believed until this excellent series attention on pack fusing :)
@@kennethalmond8922 In the event of a buss bar short, every single cell is going to supply what it can. If (in your instance) 80 out of 100 cells blow their fuses, that means that every one of those 80 cells delivered over 12 amps to the buss during the short. There is no sharing of current across any cell fuse, during normal operation. The purpose of fusing each individual cell is to stop the other cells from supply current to it in the event of a cell failure. In your case, you should seriously consider using MUCH thinner wire for fuses. In reality, if you are running 100 cell packs and have 1A fuses on each cell, you can theoretically draw 100A from that pack continuously without issue. That's over 400w per pack at 4v. Running 14s that's 5.6KW continuous available for your inverters. This is where internal resistance comes into play because though the batteries have no choice but to remain at equal voltage, they are not going to share the current evenly and so there will always be current flowing between cells during transients. You should be sizing your fuses with several things in mind. 1: the maximum current required by your inverters, shared over x cells in each pack. 2: the maximum charge current your solar system and regulators can apply to the battery at it's lowest SOC. 3: the internal resistance delta of the pack. (though I don't personally know how to apply that or how the maths works, I'd have to look into that.) Unless you are running large inductive loads from the inverters (Eg. an air compressor) which have large inrush currents at start up, 1A slow blow fuses should be more than adequate. Also, kudos on having a pack level fuse. That is a MUCH safer way to go about it. In the event of a buss bar short, not only on one pack but anywhere on the buss'/series connections, there will always be a fuse between. No matter where the short. I have always intended doing the same - fast blow ceramic's at pack level.
its fun to see you do all this, it is a strange thing that not all fuses blows no matter what fuse you use, i guess you need a more precise fuse all must go off at 1,7A no one can be a 1,9-2.0A.. i hope you find a way!
Really interesting thank you and keep em coming, we need to solve this mystery! Like someone else on here wrote, I reckon check the cells of the fuses not blown. And see if they are ok, are they able to deliver the 2A required to blow the fuse or is there something weird with them?
Hi Pete! Long time subscriber first time commenter! Love the vids even though you think they are repetitive... i end up watching them a few times over. Anyways... back to the subject... would love to see how the battery hookup cell level fusing would perform on the same pack if not too much trouble! Thanks Mate!
It took 8 amps to blow that fuse wire between two alligator clips. I'd try attaching the fuse wire to a piece of that copper wire like the bus bar uses and clip the alligator clip to one side of the fuse wire and the other clip to the chunk of copper. I'll bet it takes more amps to blow as the copper acts as a heatsink for the wire.
Length affects the wire quite a bit. Longer allows for lower pop which was at least double the length of normal use in this test, shorter takes more amps to pop due to thermal heatsink. At least thats what I have found in all my test.💥🤘
Hey pete, very interesting and it gives you stuff to think off.... i am using the glass fuses but it's a shit load off work and it looks terrible but it works... I was also looking at the option from battery hookup nikkel strip with fuse
Nice video! 2A fuse will not blow at exactly 2A because they're supposed to carry 2A load. The max current tolerance for 2A is about 4A or more. Another important factor is combining 40 pieces of 2A fuses in parallel will actually mean about 80A, the role of the fuse is to disconnect individual rogue cell and save the pack. Your next video should be to the fuse on a rogue failing test.
Flux issues maybe? I've had trouble like this with fuse wire. What I had to do was make sure I was getting the wire itself hot enough. Sometimes you can get the puddle hot, but the if the wire doesn't get hot enough before the puddle cools, the flux sticks to the wire when the puddle cools causing a poor connection. Sound crazy, but this has been an experience of mine in the past. This would need extensive testing under different conditions to prove. Someone also mentioned High internal resistance in the cells. I'd explore that too. But that doesn't explain the resistance value changing when you were touching the cells. Having an internal resistance testing station set up to make things go fast would be ideal. I just set up a load test of 2-5 amps (depending on the application) of fully charged and rested cells, and monitor the voltage when under load. If it drops below a certain voltage (of your choice) when under a load , I scrap or repurpose the cell. This all depends on your application. Like if it were a battery pack for a motor of some sort, I'd never use a cell that has too much voltage sag. I might use it for a powerwall though. But again, it depends on the application.
Pete if the capacity is a lot lover than the others there is less current drawn from them. I would test or check the cells that did not blow the fuses's capacity
Hi Pete, Great video there, clearly your new to constand current/constant voltage PSU's but you'll figure that out in time (thats what the lights mean) in terms of the thermal fuses those sound difficult to implement but perhaps using those for "Pack" level fusing would be an idea.. But in the mean time if you look but auto resetting polly fuses i think you will find the cost effective type your looking for.
Hit & miss but to locate a thermister in a pack would be the use of thermal camera to find the highest heat point so it triggers escentially as soon as possible.
Mini is fun to drive around hehe - I just checked the fuses, and they all blew at 2amps, and were all attached well, also on cells that blew on last tests sooooo...
what about ntc thermisters between all the cells? won't interrupt a fault but would mean you'd detect heater cells before they could cause too much trouble? though that's a crapload of temperature sensors
This is an idea. Could possibly work. But it would also mean needing to check the thermals with a camera quite often, which isn't a bad idea in and of itself. At this point, thermal cameras are an investment, not an expense, for this type of work.
So this little pack contains 40 cells. Each cell 2 amp fuse So you are going to draw 80amp from such a small number in a powerwall ??? Much lower would be better per cell max (as a powerwall) How many amp do you draw max per cell on your powerwall setup?? If your packs are 150 cells x 2 amp fuse = you can pull 300 amp before the first fuse wil blow. Keep the fuses as weak as possible. 1.5-2 times the max amp you pull .
I have the exact same power supply you are using in this video to test the glass fuse the only thing different I noticed on this one the display is different Either they updated it since I purchased it or it’s a difference between the US model in the Australian model
Use good quality crimps, or spot welds for thermal fuses. Or for some entertainment, ask the apprentice to solder them on until they get it right. Sidenote, the apprentice might come up with a better suggestion than I.
So what amperage fusing is needed for a cell in a pack? You sowed 2 amp and 7 amp. How many amps does the nickel strip fuse blow at? Great video been enjoying the series.
Pete, mate, thank you for all you do. But mate, my question still stands, what happens if you spot weld the fuses mate? I know the OP batteries was soldered, but, I think that this video has proven that the culprit was indeed the fuse wire. My question if you'll indulge me is this, when making a new battery, fused only on top of the cell, and SPOT welded to the cells and if possible to the buss bar, would they be more reliable? In my very honest opinion this video has proven that the fuse wire used was or is the culprit.......... Thanks Pete.
That is a intresting experiment. Glass fuses are pretty much safest option available. Looking at your the video... makes me think if smes cells didn't produce enough amps to blow a fuse? Can you measure each cell current output with safely?Also I have noticed that sometimes when glass fuse blows it creates metal vapour inside which is little bit conductive and can give confusing readings with multimeter. Good job on all of you videos Mate! Respect!
You need to determine how many amps you expecting to get out of your batteries and fuse them accordingly. I use 10s 100p setup to run a 10amp inverter, so pulling 10 amps from 100 cells is 100mA of current per cell so a 200mA fuse would be ample for my setup and even low cells will break the fuse.
I don't think the fuses were damaged. I rather think either those cells were bad, or the few fuses were another value altogether. You can test the resistance in the mOhm range of the fuses by passing a controlled 0.5A, and measuring mV over them.
I've been watching your videos as a learning experience - Thanks for all the great info as I am learning and planning a solar system. One question though. I don’t understand how your power wall batteries are configured. Are they all configures as one cell at 4v and then connected in series before attaching to your inverters? If so, what voltage are you feeding your inverters? Is there a specific video where you explain your rationale being this configuration as opposed to building a pack that puts out 12/24/36/48 volts or whatever? Thanks again.
Why fuse both sides of each cell? Most fused systems are on one side of the circuit. I am also thinking that the resistance of the fuse wire may increase when it gets hot and having 2 in the circuit may act as a current limit on a cell with high impedance.
Suggest removing 1-2 of the non-blown glass fuses and repeat power supply test done in the beginning of video. Curious if tolerance on the 5 fuses a bit higher? (doubt it) Or perhaps the short current (in main bus bar) drops as each fuse blows, and short current is lower than initial short current (each fuse blowing removes cells, so is current through the main busbar dropping?) A test would be to measure bus bar voltage as short remaining 5 cells ... likely very low. With large number cells, the voltage likely took a bit of time to drop. (what would it been as fuses began popping? No easy way to tell) Would need high speed current (and/or voltage) reading at point of short to gain better insight of what happening at point of main bus short. (ie: digital current capture .. but doubt you'd have sampling equipment)
I was thinking maybe there is a thermal sensor that could go on a ribbon, and be placed with 2sided tape to the cells of the whole pack, maybe to detect 2-4cells each, but the ideas ban get crazy deeper you go!! If you go that route, I think nickel strip on the neg. Side with a aluminum bar attached with thermal tape, to read the temp of a large group of cells, then slightly thermally insulating, to prevent the aluminum from cooling the cell, being the neg. End is closest to the internal temperature of the cells, maybe a single temp sensor could detect reliably around 16cells, surely a system could be D signed cheaply to protect a pack from over temp, maybe even connected to a cheaper BMS, someone is going to eventually solve all these issues! But it's always going to be some kind of something when using random used cells all paralled, and in series! The cells that do not blow the fuse must be high resistance, and/or has a ***high resistance connection!*** that could be it! Maybe the solder or the heat from soldering damaged the connection internally?? Or there is contamination in the solder, causing a high resistance?? It's always something!!
You can't measure continuity between two points that have a potential difference. The meter applies a small voltage to its test points and checks if a current flows to measure resistance. If there already is a voltage present on the device under test the reading will just be random. If you unsolder these fuses (or the cell on the other side) I bet you would read a very high resistance. Also when testing fuses with a switching power supply you have to be aware that your power supply has an output capacitor. This can supply a very high current at whatever voltage it is currently charged at for a short period of time. The current limit only defines at what rate this capacitor will be charged again as a sort of long term maximum average current. If you don't want that current spike the only way is to start with your load at 0V.
@@MrSummitville Let's imagine the cell with the fuse under test has 4.1V and another cell that has an unblown fuse has 4.2V (voltage differences exaggerated). Taking the positive bus bar as a reference we would measure -4.2V to the negative bus bar and -0.1V to the positive terminal of the cell with the fuse under test. This voltage will render the resistance measurement useless. Even if the cells all had exactly the same voltage (which they do not because their resting voltage will always deviate ever so slightly) all cell positives would appear "connected" because they are referenced to each other via the negative terminal. This means measuring from the bus bar to any cell will always read the combination of all unblown fuses, even when measuring on a cell which actually has its fuse blown.
@@JonaJona Regardless of what you "imagined", using the continuity setting does find blown vs un-blown fuses. Does the continuity setting on your meter, not work for you?
I’m going to guess that the internal resistance of the ones that didn’t blow are too high to allow for anything over or near 2 amps to flow. I’m sure this has been said. Check the IR of the batteries that did blow the fuse and the ones that didn’t. I’m sure they will be different.
i have so many videos it's imposible to go back and fix them as they break. Would be neat if youtube had a tool to check this!! I know you can do it with the API but i'm not that smart
A 2 amp fuse is designed to carry 2 amps not blow at 2 amps. The current it blows at is determined by the job it is designed to do. I expect your fuses are around 1 amp carrying capacity from your video. Just an idea about not all fuses blowing during a dead short. If there is a high resistance in the Klixon attached to some of these second hand cells, expect funny stuff. Since you know which cells are implicated, load each individually and calculate resistance of the cell including the Klixon at say 2 amps. The mere act of soldering can oxidize the contact or detemper the diaphragm. Battery packs that cause intermittent laptop issues are likely to have a cell with a shitty Klixon anyway. The end result for you in normal use is an 80p pack that is really 80 minus the number or shitty Klixons. While I was proof reading, a though came. An intermittent Klixon can cause cells to become chronically undercharged in a pack that is in service. Cheers
Very informative. 6:35 first thought that came to mind was great he fried himself😐. I wonder those 5 fuses didnt pop. On those thermal fuses maybe solder a connector that you can just plug in the the fuse, just an idea but I do see them soldered all the time maybe they pop after a certain amount of time with whatever temp they are rated perhaps try seeing how long it takes for them to pop with a soldering iron. 4 dollars?!!!!! Wow. Must be made with unobtanium. Again Great vid. Pls keep them coming👍👍 I'll see if I can drop some bucks off at your patreon.
with the not resetable fuses. DO it like its in Laptop Batteries, solter them to short nickel strips and than spot weld this nickel to the cells and solder on the busbar.
Curious on the fuses that didnt blow, did they have a different resistance between the cell and busbar? Also is it worth pulling the cells that didn't blow for a quick capacity test to see if they are lower capacity than advertised? Perhaps what once was 2200mha is now 1400 (ie not enough current to blow)?
I am a bit of a battery virgin, so excuse my uninformed question, but if a fuse level pack experiences an actual in use dead short that blows most of the fuses and the problem is not noticed, is there a chance that the charge device (whatever the device may be) will continue to try to charge the few cells left to destruction or will the remaining fuses finally blow and/or will the charge device detect the problem and shut down the charge. In other words, if the pack in use and not noticed in the short condition, will the remaining fuses eventually blow or will the cells continue to cook until something happens until they are completely destroyed?
75C is probably extremely too late to protect an 18650 from blowing up. Also this just goes to show that everything can look well connected but it might not be. so check your cell connections!
Many types available. here is one rated at 1.1A 60V. Try searching in Digikey or Mouser for PTC Resettable Fuses. www.digikey.com/en/products/detail/bel-fuse-inc/0ZRP0110FF1E/9468256
Didn't you used to have more videos on this channel? I was looking for a one where you installed a safty container with your wife.. but couldn't find it?! also the ones on the mini conversation Im looking for.. Maybe I got you confused with some other joey but I believe it was you
So has his fire basically come down to the over rated fuse wire? was he expecting each cell to output 8A under load for his use case, was he expecting to much? or was it just a mistake and would a 2amp fuse blow when a cell turned into a heater?
@Anthony Barrett - You will never know what actually caused he fire. You can makes guesses. a) maybe it was a "heater" cell ... b) maybe it was bad "fuse wire(s)" ... c) maybe it was poor construction ( caused a short ) ... d) All of the above ... e) some of the above ... f) none of the above ...
@Repairman Even with a 2 Amp Glass Fuse, a "heater" cell can still burst in to flames. So, was the 7 Amp Fuse really the source of this problem, or just another problem?
That test is next well soon, i have other commitments to deal with first. Unless for some weird reason I make a million bucks from TH-cam this month that is..
my opinion those fuse did not blow up same time because some battery are different internal resistance so i believe if you use new battery all same chemistry like IMR if you mixed between them lime IMR then NCR so some fuse will not blow up some will so if you try new batter match all things i said like same chemistry same cycle same internal resistance
I don't get it. Fuses are a safety device, but soldering them, especially to the center of the cell, damages the cell. So you're damaging the cell to install a safety device in case the cell fails, increasing the likeliness that the cell fails. If we're going to copy the tesla style pack and use fuses, why not include other knowledge from those same packs. They use vibration to weld the fuses on. Of course a DIY pack builder doesn't have access to that tech, but we have access to plenty of cheap DIY spot welders that would minimize heat to the cell. We know heat to the center of the terminal is extremely damaging to the cell, to the point where factory made packs use nickel strips that have the center of the cell removed to help stop any heat from getting there. So why would we ever apply our connections to the center of the cell? What are we doing, if anything, for thermal management? What are we doing, if anything, for a dustproof, fireproof enclosure? If we're just cherry-picking the easy safety precautions to follow and then ignoring the other ones, that isn't safety, that's theater. Have you considered cutting small nickel tabs, and soldering the fuse to the tab, and then spot welding the tab to the cell? Time consuming, but it allows you to basically use the same method you've used here without putting a glob of solder in the center of the terminal and while minimizing heat to the cell.
All these tests in past few video stemmed from how someone did it.. now how we should do it moving forward - however I'm sure someone will move forward different from this playing I've been dong.
Dude, when a cell fails, it's going to fail regardless of whether a fuse is present or not. The best that the fuse can do is protect the cell from external short circuits. These glass fuses are great for this purpose and they are reliable! The best way to go would be to purchase brand new protected 3500mah batteries, they are very well protected and your battery bank will be super neat and tidy but it's gonna cost ya!
@@PeterMilanovski Yes, which is why I'm pointing out that the fuse is only 1 part of the safety picture, and I don't get the point of using a fuse but not taking very basic precautions like not soldering or at the very least keeping your connections away from center.
@@HBPowerwall there's not enough videos on this topic and if there was, they are to short, either they are deliberately made short or stuff gets left out onto the cutting room floor... Yeah there's always someone who complaining about video length, I know because I was one of those people, well I didn't complain in the comments but I avoided the channel only to re find it again at a later date and realized what I had missed out on! I went right through the whole channel and watched every single video, they run for at least one hour minimum! I have seen others complaining about video length but it's their loss as it was mine before them! Now I click like even before I watched the latest video! What you are doing here is unique, going through the process of finding the best method of protection is fascinating viewing, I know that I'm not board! LoL I could easily watch you test different ideas for 11 hours straight let alone 11 minutes, besides, blowing up fuses is fun, I know, have done it may time's both deliberately and accidentally... I don't know if my suggestion is worthy of a mention but it just came to me as I was typing this out, Another possibility might be PTC fuse, it looks like a ceramic disc capacitor, you would have to shrink wrap it's legs but once done, you can fold it over and place it in between the batteries, heat makes them trip faster as does excessive current! And they are self resetting! So long as they don't get damaged.... I use them on speakers, when they trip, it sounds like someone has just turned down the volume! They stay tripped until the volume is turned down or short circuit removed.... I'm not sure how they would go in this application, they come in different wattage ratings and you can parallel or series them to get the desired outcome, they should be available from jaycar, I know that I have got some form there age's ago but since discovered that if I'm prepared to wait, I can get 10 for the price of one from jaycar over on eBay!.. actually I believe that they are called PTC resistor's, even though they are resettable fuses...
@@caramelzappa I get what you are saying about soldering the cells, I personally haven't come across any real information regarding the heat from a soldering iron, let alone what it does to a cell if it's done more than once... I know that people do it, I haven't myself, I purchased those plastic spring loaded cell holder's from eBay, they are cheap, quick to pull out a cell and I can have a single cell protection PCB board for every cell underneath it and I can keep all the cells tied in with one neat zip tie... But my method means that I have to charge all the cells at 4.2V! Even if the output from the protection PCBs are wired up in series... The output only needs one fuse! As the PCBs cover everything else, over and under voltage! Short circuit... And because they are in this configuration, they are naturally balanced! Each PCB will stop charging it's cell when it's full while having no effect on the others! The PCBs are really cheap and they stay with the battery holder meaning that you don't have to use expensive protected cells... Well that's how I have mine set up... I guess that there's hundreds of other ways to do it, the heater cells are a worry, my cell holder's are plastic! But I'm only using new 3500mah cells and I'm only pulling 500ma from each! Although a thermal camera is next on my list of things to get!
How do you know that you have "... no issues at ..." ??? Did you short out the pack? Do you have video showing that every fuse, in the pack, will actually blow?
1 because i have tested every cell 3times 2 this batterys have only bin tested once.... 3 thermal issues have some parallel issues like self discharging or high internal resistance .....by full and when they are empty... 4 equipment that u use shuld not be mass produced 20$ diagnose Bt-c3100 is inacurate .... First charge of salvage batterys shuld not be more than 0.15A ... Yes is long first charge but in this stage u get first heaters because batterys are charging long time ....time of first charge shuld also tell u someting is not ok... If batt. is ok no heat will build up ect ... 5 by testing capacity with 0.5A ...discharging....no heating up SkyRC mc3000 is great option to use ... Calibrated .... 6 waiting time 5-7days ....first charge to exacly 4.2v then put batterys to rest... after5-7days measure the voltage ..if is bellow 4.17v is no god for powerwall 7 pack asembly .....asemble the pack... Charge to 4.2v and put to resting for 5-7days again if is below 4.17v charge pack again and serch for heaters thermal gun ect... Then disconect all batterys on the one side ....i do on the neg because on pos i have glass fuses ...wait 5-7days and measure every cell replace the cells that are no god....asemble the pack charge to 4.2v and repeat the procedure until u get 4.2v on the whole pack after week of resting.... 7 measure capaciti of the whole pack with ZPB30A1 V2.8 my device.... I use 6packs/135Ah in parallel and 14 in series Mach capacity batterys thogether one 2000mA and above Second 1900mA 3 1800mA and so on down to 1300mA so every 1s group have 2000 and above have 1900 have 1800 an so on ... Usebal capacity is 600Ah/52v ....active balancing is required 50-90€ with display and constant balancing .... Max draw is 100A long term...also charging after 3.4v i consider cells as empty and 4.04 are full .....and i get my 600ah wit on issues...
Man i have tested cells like 3years and look all videos hb powerwall and others also make mistakes along the way 3times have taken all packs a part and it still was not perfect ...then u take paper pencil and wrote every mistake i have made and look also other ...adopt god things.... Hb is cool guy ....but i think his packs are simply too large .... That burning pack was just extemly abused ... And balancer it must be active because are old batteries at least 5A shifting current capabily ....mixed batteries act different at 3.3v and 3.8v curve of discharge is not linear and every so small disadvantage could active balancer make to disspeare.... it have to be constant balancing. even now if i go look battery volages i see that is shifting current around ... Now days good active balancers cost 80-90€ with display or monitoing capable .... My batterys lie on the same spot more than 2 years now without any intervention... On sunny days i charge them with over 100A constantly no isses....
@@HBPowerwall I completed over a thousand successful welds between relatively thick nickel tabs and it does the job great. No complaints other than the device heats up a bit. I highly recommend getting one if you need to weld but can't justify the €200+ for a bigger unit. I added solder to the device I got and it helped me get a lot of welding done quickly.
@@HBPowerwall I would say they are capable for most projects most people do. My point is they certainly do their job while costing almost nothing compared to other units. Definitely a worthwhile investment if you need a few hundred to a few thousand welds.
Glass fuses are far better then just having a fuse wire in free air. This is a reason why they are encapsulated as well. As it keeps the fuse wire in a stable environments and allows it to blow as a set amps. The fuse wire in mid air has so many variables it’s not ideal at all
The thermal fuses are no better than the glass fuses in this situation. The cells that are not blowing the fuse have a problem of some kind and are not able to provide the energy to blow the fuse. Probably the IR is higher and the meter you use may not be able to discern it as I don't know how it measures it I can't comment. 1. If you take those cells out and test them by shorting them with thicker wire and your clamp meter measuring the current I think you will see they can not provide the current. 2. Do the same with a cell that blew the fuse and you will see a big difference. 3. The ones that do not blow the fuse if left in a short condition do they over heat?
Really seems to me like the cells that didn't blow their fuses just aren't capable of providing the amps needed, and are quite probably faulty. Maybe pull some from the pack and using a current monitor see how much current passes through a wire dead shorting the cell.
Because it is 100's of extra failure points, looked ugly, is more expensive, and doesn't add that much more safety in this application. Already use fuse wire rated at about 3-5 amps for years, and never had one fail.. Fuses are for holy fuck moments - massive dead short of some description. These or even my current fuses still don't blow when a cell is faulty and self-discharging and heating up.
So what's the idea behind the fuses? I get that it's a protection but watching these last few videos it seems that the dodgey cells don't have enough energy to blow the fuse, whereas the better cells blow it right away. Also, the testing you're doing is simulating an external dead short. Wouldn't a fuse on the cell be better? If the pack had an internal failure, then would a single battery actually be over supplying the current that makes it fail? to understand the fuses, my best guess would be to test batteries in various conditions (full/mid/end of life) with a load and fuse to see how it reacts. The more I think about it, the more I feel the fuses add nothing more than a false sense of security - sorry bro...
I think you're not really doing this video justice unless you measure the current those (individual) cells are delivering on a dead short. Just remove the cells that did not blow and put you ammeter in line with the fuse and then short it out. I think what you'll find is that although these cells show full voltage when charged, they are likely unable to deliver more than an amp or so which means they will never be able to blow the fuse. I think what your highlighting here is one of the risks taken when using used cells from hundreds or thousands of different sources, all of different ages and all with different usage histories and then putting them together in a pack to act as one cell. Obviously even with the best care taken in testing and selecting cells, you really cannot determine age and you are bound to run into really all sorts of weird types of failure. I think if you do this test again with brand new cells, you will find that every single fuse blows as expected. Which would be a really good test to highlight the differences in behavior for your viewers! Great job with these videos mate!
![ค้างคืนโรงเก็บกระสวยอวกาศร้างกลางทะเลทราย [Around The World Ep. 3]](http://i.ytimg.com/vi/E5bWZQhABJE/mqdefault.jpg)
Cells that did not blow the fuse are defective, not able of supplying 2 A into a short. Try one of the cells that did not blow its fuse and see how many amps it will provide into a dead short. (My guess is: almost nothing). Unless You break the fuse glass they are surprising rigid. I have mounted 7000+ of these and I have less than 1% that breaks.
Yes I was thinking the same, clamp the current meter on the bus bar wire to see what current there still is on those cells that did not blow their fuses.
Agreed, I have had batteries that show voltage but provide very little current .
@@OverUnity7734 Open circuit voltage is what that is
This is where a battery load tester comes into play during the processing stage. The ZTS MBT-1 pulse load tester is what Ive been using for a couple years now. It looks kinda cheap looking for what it costs but its actually really rugged.
Maybe check the cell’s internal resistance to see if it’s very high as a cause for them not blowing the fuse?
Great set of safety videos lately, I think a lot of people appreciate them, thanks!
Some fuses didn’t pop so I think the following should be investigated:
1. Are the fuses themselves faulty ( put current over them with your PS and test it). If yes, the fuses themselves or installation method should be questioned. If not...
2. Check if the cells of which the fuses didn’t blow, have peculiar behavior. Heaters, drainers, high internal resistance, low capacity left, ... if this is the case we should try to figure out a method to detect this during initial cell testing so they never end up in a pack. That is of course if the problem is already present from the beginning and not caused during aging of the pack.
Re 1: I have actually come across one faulty fuse. There were 2 fuse wires inside the glass tube together with 2 leads in each end 🙂 , well I discarded that one.
Interesting results! Thanks for this video.
Fuses take a different amount of time to blow depending on the current. This can be checked via their “I2T” curves in the datasheet. Those curves show the time versus current before the fuse will blow. Since each battery has a different internal resistance that means each will output a different amount of current when the pack is shorted and each fuse will take a different amount of time to blow. Fuses have a tolerance too, not all will blow at the exact same time for the same current level. Lastly, different lead lengths for each fuse results in different levels of heat being conducted away from the fusing element. This can affect the amount of time it takes to blow the fuse, especially if the current levels aren’t high enough to instantly pop it.
Short the leads together to set your current limit.
This. Or just turn the current limit all the way down. Attach the fuse, then slowly turn the current limit up.
Blow the fuse first, then read instructions...
Nar post to TH-cam get told then read
I do follow and watch your videos. What I know with used cells is some have a very high internal resistance (although the capacity and discharge test passed) so the fuse may fail to burn as it should.
it is realy important to have cells with low IR, IR is direcly linked to the health of your cells....there is a guy at second life storage his name is wolf he made a study how IR relates to the health of cells.
I have also a 18650 48 volt 150 ah bank and are IR and mah matched my bank are realy balanced 0.003 volt difference
The fuses that did not blow were likely a damaged in hook up or poorly connected, this bears out in the fact that you had to press and move the fuse around to get a decent contact, even this though is a better result as it shows a disconnect in voltage to the bus bar where the previous fuses still had full contact.
Thanks for doing these videos as they are a great help to many people.
I hope they help, it's just me messing around then sharing.
He's soldering directly to the cells. My guess is he has cold solder joints on the negative side of the cells.
those non resetable thermal fuses are probably for mounting inside transformers touching the coils, they will blow up when the transformer gets over a certain temperature
They go into toasters, HWS etc apparently
They're very popular in Rice Cookers. I sold dozens when I worked at >Jaycar 20 years ago...
For the thermal fuses, it is recommended to use a crimp or spot weld to install them. If you have to solder them you will want to use something like a cold wet rag or even an ice cube around the body and in the connecting wires of the fuse depending on the temperature rating of the fuse to keep them from failing during installation.
I have a power supply just like that. Very handy. I've found that the glass fuses break at roughly twice their current rating. If the fuse wire doesn't break until 8A, I'm not sure what use they would be unless you're using several amps per cell normally. I've also found that a small number of glass fuses are defective in each package I buy. So I check each one before I install it. With practice, they can be made to look nice on a battery.
A few points, if you will. The glass fuse you tested blew at 1.75 A or so, which indicates that it's rated something between 0.5 and 1 A, as others have already stated. Now, if there's any way you could get the pack to an electronics lab, here's how I would test it: hook it up to a DC electronic load. Monitor pack voltage and current with an oscilloscope (you need a shunt resistor or current probe for this). Only connect as many cells in parallel as the current rating of the measurement system allows - you can measure the pack in segments if necessary. Ramp up the current at the electronic load, and monitor the pack with a thermal camera. Try various loads and patterns (like for example a short peak load over a base load) and see what happens. (That's how I test power supplies - only I'm a bit far away...)
One possible idea re thermal protection would be to install a thermal sensor between every four cells (so a 40p pack would have 10 sensors). These might be PTC resistors in series, so that any one cell heating up past a certain temperature would cause the entire chain to go high resistance. This in turn would trip a circuit breaker for the whole pack (or have the BMS disconnect it) and trigger an alarm.
The way I see it, individual fuses will help in some situations, for example when an individual cell is being dangerously overloaded for any reason that isn't caught by a downstream protection device. However, there are serious failure modes where no fuse does any good, such as an individual cell going high resistance. Also, high internal resistance can be a symptom of something very serious that would warrant immediate disconnection from load - but this is something that a fuse fails to catch. In fact, high enough internal resistance can prevent the cell fuse from blowing at all.
in lieu of a scope i test my batteries with a cheap ZKETCHE EBD-USB Voltage and Current Monitor and can even save the plots on their software program supplied with it.
@@charleskeller4288 That's good.
I've always used those glass fuses and they always worked very well on all my 18650 packs. Works perfectly. Was a recommendation from AverageJoe!
Yep, that's why i got these fuses years ago.. did a few small projects with them but never grew on me.
Would be interesting to see the IR of the cells that didn’t pop the fuse and that did, couple of other people have mentioned this too. Also another test would be to dead short those single cells one at a time with a multiple meter inline to see what amps it is able to sustain during and compare to other cells see if there is a difference
Important is the voltage over the fuse. The fuse wire in the lenght shown the supply shows 1V and the wire only glowing dark. Then you have both cell sides fused so 2v over the fuses to pop them. No margin for higher IR cells there. Fuse on the cells should only have 0.5v drop when breaking
Those 5 fuses that didn't blow might have been on batteries with high internal resistance / batteries that can't deliver the required 2A. I hope that's the case, otherwise the fuses are bad. Damaged fuses would burn out *sooner*, not later.
The voltage spiking when you pressed the busbar was probably from your hand conducting from healthy cells to the bus ;)
Some calibration and testing would need to be done but, sensing the resistance of the pack with a custom circuit and tripping a shunt trip breaker for that particular pack when the resistance drops below a threshold (dead short). Don't have a pack to test with, but this method does work on larger industrial battery backup systems. Thanks for the videos btw :) Cheers from Canada
The problem with some/many PSUs is they have an electrolytic on the output so if you set a constant current, limiting does not start until the cap has discharged. The way around this would be to short the output, set the current limit, attach the load and only then remove the short.
Never in a million years, would I have believed that "fuse wire" would carry almost 9A. That's insane! This is why glass fuses are a better alternative. You know what you're getting (within tolerance).
Those thermal fuses are of no use to you, unless you intend to strap them to the side of every single cell and even that would be of limited use, seeing as the thermal fuse temp is so high. Their intended use is in appliances with a thermal element or similar (the side of a motor for example) as a fail safe (usually secondary).
It really is beginning to look like the only way to make these installations safer, is 1: containment of packs, and 2: a sensor matrix that monitors literally every cell looking for heaters.
www.ebay.com.au/itm/50PCS-MF52AT-MF52-MF52B-3950-NTC-Thermistor-Thermal-Resistor-5-10K-50K-100K/193240413757?_trkparms=aid%3D1110009%26algo%3DSPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20201210111452%26meid%3D565190a3b0c943a58f6d352d9ec09b1e%26pid%3D101196%26rk%3D7%26rkt%3D12%26mehot%3Dnone%26sd%3D201415005626%26itm%3D193240413757%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3Ddefault&_trksid=p2047675.c101196.m2219
www.ebay.com.au/itm/10pcs-NTC-Thin-Film-Thermistor-100K-precision-1-MF5B-SMD-for-3D-Printer/201415005626?hash=item2ee54515ba:g:A8cAAOSwBLlVWxJX
There must be a cheaper way to procure them in bulk. If people are interested I will start designing some sort of data acquisition/monitor capable of handling 1000's of sensors.
The "fuse wire" can vary, too, depending on the quality of the copper used and/or if it's copper clad aluminum (CCA) (some use networking cable for fuses which some of it is called CCA. This is cheaper networking cable, but the cable is much less flexible). This can be an issue if you've ended up mixing different brands or spools of wire to make the fuse links.
This is also why if someone chooses to go this route "they" must test the fusing capability of their wire, not just go off of some YT video and call it good enough.
@@korishan For a very long time (VERY, so long in fact that I've forgotten where I read it. Probably in an EA magazine some time in the 90's) I always was of the belief that a single strand of "Telecom wire" which was solid, single strand copper phone wire used by Telecom, now Telstra, was good for 2-3 amps and relied on that knowledge as a rule of thumb. I have doubted that it would fuse at 3A for some years, but never bothered to test it or any other wire for CSA vs current carrying capability.
Having watched that, I'm going to do some research into it. It's not knowledge I've really needed before but now I'm curious to know.
I use 30AWG tinned copper for my fuse wires. I'm of the impression they melt at 12-20a based on my 'loose' tests. I never expected all fuses to blow in a pack short. I expect the minority (e.g. 1 bad cell) fuse to melt/disconnect based on the amps of the other 50 or 100cells. When it gets down to 5 cells left of 100 cells - still connected to the bus because the fuse wires didn't 'blow'... that makes sense to me. The 5 or 4 or 3 cells may not have have amps to melt 30awg at 20a... they just dead-short and run down. BUT I also don't expect these remaining 5 or 4 or 3 cells that can't muster 20a to catch fire. So I'm confused at the notion that all cells would disconnect from the buss at battery short. This is why I also fuse the 'battery' as a whole. Again, there are 2 events here in my mind - the BIG SHORT - which hopefully will trip the battery level fuse and/or most of the fuse wire... but there is a post situation where there could be some power left in the battery - not enough to burn remaining fuse wire. I'm not saying that my understanding is correct - just something I've believed until this excellent series attention on pack fusing :)
@@kennethalmond8922 In the event of a buss bar short, every single cell is going to supply what it can. If (in your instance) 80 out of 100 cells blow their fuses, that means that every one of those 80 cells delivered over 12 amps to the buss during the short.
There is no sharing of current across any cell fuse, during normal operation.
The purpose of fusing each individual cell is to stop the other cells from supply current to it in the event of a cell failure.
In your case, you should seriously consider using MUCH thinner wire for fuses. In reality, if you are running 100 cell packs and have 1A fuses on each cell, you can theoretically draw 100A from that pack continuously without issue.
That's over 400w per pack at 4v. Running 14s that's 5.6KW continuous available for your inverters.
This is where internal resistance comes into play because though the batteries have no choice but to remain at equal voltage, they are not going to share the current evenly and so there will always be current flowing between cells during transients.
You should be sizing your fuses with several things in mind.
1: the maximum current required by your inverters, shared over x cells in each pack.
2: the maximum charge current your solar system and regulators can apply to the battery at it's lowest SOC.
3: the internal resistance delta of the pack. (though I don't personally know how to apply that or how the maths works, I'd have to look into that.)
Unless you are running large inductive loads from the inverters (Eg. an air compressor) which have large inrush currents at start up, 1A slow blow fuses should be more than adequate.
Also, kudos on having a pack level fuse. That is a MUCH safer way to go about it. In the event of a buss bar short, not only on one pack but anywhere on the buss'/series connections, there will always be a fuse between. No matter where the short. I have always intended doing the same - fast blow ceramic's at pack level.
its fun to see you do all this, it is a strange thing that not all fuses blows no matter what fuse you use, i guess you need a more precise fuse all must go off at 1,7A no one can be a 1,9-2.0A.. i hope you find a way!
Really interesting thank you and keep em coming, we need to solve this mystery!
Like someone else on here wrote, I reckon check the cells of the fuses not blown. And see if they are ok, are they able to deliver the 2A required to blow the fuse or is there something weird with them?
Hi Pete! Long time subscriber first time commenter! Love the vids even though you think they are repetitive... i end up watching them a few times over. Anyways... back to the subject... would love to see how the battery hookup cell level fusing would perform on the same pack if not too much trouble! Thanks Mate!
I would too, just time poor at the moment and have three other videos i need to finish editing.. but i will get there and do that video again.
It took 8 amps to blow that fuse wire between two alligator clips. I'd try attaching the fuse wire to a piece of that copper wire like the bus bar uses and clip the alligator clip to one side of the fuse wire and the other clip to the chunk of copper. I'll bet it takes more amps to blow as the copper acts as a heatsink for the wire.
Length affects the wire quite a bit. Longer allows for lower pop which was at least double the length of normal use in this test, shorter takes more amps to pop due to thermal heatsink. At least thats what I have found in all my test.💥🤘
Hey pete, very interesting and it gives you stuff to think off.... i am using the glass fuses but it's a shit load off work and it looks terrible but it works...
I was also looking at the option from battery hookup nikkel strip with fuse
Nice video! 2A fuse will not blow at exactly 2A because they're supposed to carry 2A load. The max current tolerance for 2A is about 4A or more. Another important factor is combining 40 pieces of 2A fuses in parallel will actually mean about 80A, the role of the fuse is to disconnect individual rogue cell and save the pack. Your next video should be to the fuse on a rogue failing test.
Test the fused nickle strip using the same method 2:01. I am interested in seeing how much current it will take before it blows.
Flux issues maybe? I've had trouble like this with fuse wire. What I had to do was make sure I was getting the wire itself hot enough. Sometimes you can get the puddle hot, but the if the wire doesn't get hot enough before the puddle cools, the flux sticks to the wire when the puddle cools causing a poor connection. Sound crazy, but this has been an experience of mine in the past. This would need extensive testing under different conditions to prove.
Someone also mentioned High internal resistance in the cells. I'd explore that too. But that doesn't explain the resistance value changing when you were touching the cells. Having an internal resistance testing station set up to make things go fast would be ideal. I just set up a load test of 2-5 amps (depending on the application) of fully charged and rested cells, and monitor the voltage when under load. If it drops below a certain voltage (of your choice) when under a load , I scrap or repurpose the cell. This all depends on your application. Like if it were a battery pack for a motor of some sort, I'd never use a cell that has too much voltage sag. I might use it for a powerwall though. But again, it depends on the application.
Pete if the capacity is a lot lover than the others there is less current drawn from them. I would test or check the cells that did not blow the fuses's capacity
Hi Pete, Great video there, clearly your new to constand current/constant voltage PSU's but you'll figure that out in time (thats what the lights mean) in terms of the thermal fuses those sound difficult to implement but perhaps using those for "Pack" level fusing would be an idea.. But in the mean time if you look but auto resetting polly fuses i think you will find the cost effective type your looking for.
Hit & miss but to locate a thermister in a pack would be the use of thermal camera to find the highest heat point so it triggers escentially as soon as possible.
Love the Mini, cant wait to see more of it
the glass fuses seem like an improvement but im still wondering why they don't all blow
Mini is fun to drive around hehe - I just checked the fuses, and they all blew at 2amps, and were all attached well, also on cells that blew on last tests sooooo...
what about ntc thermisters between all the cells? won't interrupt a fault but would mean you'd detect heater cells before they could cause too much trouble? though that's a crapload of temperature sensors
This is an idea. Could possibly work. But it would also mean needing to check the thermals with a camera quite often, which isn't a bad idea in and of itself. At this point, thermal cameras are an investment, not an expense, for this type of work.
So this little pack contains 40 cells.
Each cell 2 amp fuse
So you are going to draw 80amp from such a small number in a powerwall ???
Much lower would be better per cell max (as a powerwall)
How many amp do you draw max per cell on your powerwall setup??
If your packs are 150 cells x 2 amp fuse = you can pull 300 amp before the first fuse wil blow.
Keep the fuses as weak as possible. 1.5-2 times the max amp you pull .
09:24 use 🎧 & increase the volume.
The Jurassic park. lol
lol
@@HBPowerwall Haha... Yes Sir it's sounds like.
I have the exact same power supply you are using in this video to test the glass fuse the only thing different I noticed on this one the display is different Either they updated it since I purchased it or it’s a difference between the US model in the Australian model
Use good quality crimps, or spot welds for thermal fuses. Or for some entertainment, ask the apprentice to solder them on until they get it right. Sidenote, the apprentice might come up with a better suggestion than I.
So what amperage fusing is needed for a cell in a pack? You sowed 2 amp and 7 amp. How many amps does the nickel strip fuse blow at? Great video been enjoying the series.
Do you think the spot welder would be quick enough to not trip the heat fuses
Pete, mate, thank you for all you do. But mate, my question still stands, what happens if you spot weld the fuses mate? I know the OP batteries was soldered, but, I think that this video has proven that the culprit was indeed the fuse wire. My question if you'll indulge me is this, when making a new battery, fused only on top of the cell, and SPOT welded to the cells and if possible to the buss bar, would they be more reliable? In my very honest opinion this video has proven that the fuse wire used was or is the culprit.......... Thanks Pete.
That is a intresting experiment. Glass fuses are pretty much safest option available. Looking at your the video... makes me think if smes cells didn't produce enough amps to blow a fuse? Can you measure each cell current output with safely?Also I have noticed that sometimes when glass fuse blows it creates metal vapour inside which is little bit conductive and can give confusing readings with multimeter.
Good job on all of you videos Mate! Respect!
You need to determine how many amps you expecting to get out of your batteries and fuse them accordingly. I use 10s 100p setup to run a 10amp inverter, so pulling 10 amps from 100 cells is 100mA of current per cell so a 200mA fuse would be ample for my setup and even low cells will break the fuse.
Did you flip over the battery and check the back ?
Fair bit of difference between 2A and 8A.
i get you need a fuse but real danger of those cells is a internal short leading to a fire right and that fuse would not help that correct?
the thermal fuses have a mechanical connection use alot in fan heaters where the terminals are crimped
I don't think the fuses were damaged. I rather think either those cells were bad, or the few fuses were another value altogether.
You can test the resistance in the mOhm range of the fuses by passing a controlled 0.5A, and measuring mV over them.
Love it going back ill try to smash the like button on videos j may have missed
531👍's up thanks again for taking us all along with you for the great news
I've been watching your videos as a learning experience - Thanks for all the great info as I am learning and planning a solar system. One question though. I don’t understand how your power wall batteries are configured. Are they all configures as one cell at 4v and then connected in series before attaching to your inverters? If so, what voltage are you feeding your inverters? Is there a specific video where you explain your rationale being this configuration as opposed to building a pack that puts out 12/24/36/48 volts or whatever? Thanks again.
This post SHOULD help secondlifestorage.com/index.php?threads/hbpowerwall-official.176/post-867
Why fuse both sides of each cell? Most fused systems are on one side of the circuit. I am also thinking that the resistance of the fuse wire may increase when it gets hot and having 2 in the circuit may act as a current limit on a cell with high impedance.
I guess because telsa fused both sides if I had to guess.. but yes it would limit current flow
Suggest removing 1-2 of the non-blown glass fuses and repeat power supply test done in the beginning of video. Curious if tolerance on the 5 fuses a bit higher? (doubt it)
Or perhaps the short current (in main bus bar) drops as each fuse blows, and short current is lower than initial short current (each fuse blowing removes cells, so is current through the main busbar dropping?) A test would be to measure bus bar voltage as short remaining 5 cells ... likely very low. With large number cells, the voltage likely took a bit of time to drop. (what would it been as fuses began popping? No easy way to tell)
Would need high speed current (and/or voltage) reading at point of short to gain better insight of what happening at point of main bus short. (ie: digital current capture .. but doubt you'd have sampling equipment)
I was thinking maybe there is a thermal sensor that could go on a ribbon, and be placed with 2sided tape to the cells of the whole pack, maybe to detect 2-4cells each, but the ideas ban get crazy deeper you go!! If you go that route, I think nickel strip on the neg. Side with a aluminum bar attached with thermal tape, to read the temp of a large group of cells, then slightly thermally insulating, to prevent the aluminum from cooling the cell, being the neg. End is closest to the internal temperature of the cells, maybe a single temp sensor could detect reliably around 16cells, surely a system could be D signed cheaply to protect a pack from over temp, maybe even connected to a cheaper BMS, someone is going to eventually solve all these issues! But it's always going to be some kind of something when using random used cells all paralled, and in series! The cells that do not blow the fuse must be high resistance, and/or has a ***high resistance connection!*** that could be it! Maybe the solder or the heat from soldering damaged the connection internally?? Or there is contamination in the solder, causing a high resistance?? It's always something!!
You can't measure continuity between two points that have a potential difference. The meter applies a small voltage to its test points and checks if a current flows to measure resistance. If there already is a voltage present on the device under test the reading will just be random. If you unsolder these fuses (or the cell on the other side) I bet you would read a very high resistance.
Also when testing fuses with a switching power supply you have to be aware that your power supply has an output capacitor. This can supply a very high current at whatever voltage it is currently charged at for a short period of time. The current limit only defines at what rate this capacitor will be charged again as a sort of long term maximum average current. If you don't want that current spike the only way is to start with your load at 0V.
He measured continuity between Positive power wire and the Positive cell terminal = the exact same potential. We do not need to unsolder the fuses.
@@MrSummitville Let's imagine the cell with the fuse under test has 4.1V and another cell that has an unblown fuse has 4.2V (voltage differences exaggerated). Taking the positive bus bar as a reference we would measure -4.2V to the negative bus bar and -0.1V to the positive terminal of the cell with the fuse under test. This voltage will render the resistance measurement useless.
Even if the cells all had exactly the same voltage (which they do not because their resting voltage will always deviate ever so slightly) all cell positives would appear "connected" because they are referenced to each other via the negative terminal. This means measuring from the bus bar to any cell will always read the combination of all unblown fuses, even when measuring on a cell which actually has its fuse blown.
@@JonaJona Regardless of what you "imagined", using the continuity setting does find blown vs un-blown fuses. Does the continuity setting on your meter, not work for you?
I can assure you, my meters all work well when used correctly :)
@@JonaJona My meter finds every blown fuse and every good fuse, with 100% accuracy So your "problem", must be with you ...
why not use a spot welder?
Because the OP battery didn't... Also spot-welding to soldered batteries will be no fun at all .
Very nice. Thanks for sharing
Awesome definitely wanted to see
thanks for sharing 👍
I’m going to guess that the internal resistance of the ones that didn’t blow are too high to allow for anything over or near 2 amps to flow. I’m sure this has been said. Check the IR of the batteries that did blow the fuse and the ones that didn’t. I’m sure they will be different.
Nice work!
Some of your ebay links are not active but love this video
i have so many videos it's imposible to go back and fix them as they break. Would be neat if youtube had a tool to check this!! I know you can do it with the API but i'm not that smart
A 2 amp fuse is designed to carry 2 amps not blow at 2 amps. The current it blows at is determined by the job it is designed to do. I expect your fuses are around 1 amp carrying capacity from your video.
Just an idea about not all fuses blowing during a dead short. If there is a high resistance in the Klixon attached to some of these second hand cells, expect funny stuff.
Since you know which cells are implicated, load each individually and calculate resistance of the cell including the Klixon at say 2 amps.
The mere act of soldering can oxidize the contact or detemper the diaphragm.
Battery packs that cause intermittent laptop issues are likely to have a cell with a shitty Klixon anyway.
The end result for you in normal use is an 80p pack that is really 80 minus the number or shitty Klixons.
While I was proof reading, a though came. An intermittent Klixon can cause cells to become chronically undercharged in a pack that is in service.
Cheers
Thats correct, mains voltage fuses that have designed carrying capacity blow at double -so 6A fuse blows at 12A in about 30 seconds
You don't think the capacity testing would show up these cells ?
And/or performing a resistance test
@@chriskennedy7534 i suppose it would, but since bad cells are removed when building packs, how would you retest them once in service?
Very informative. 6:35 first thought that came to mind was great he fried himself😐. I wonder those 5 fuses didnt pop. On those thermal fuses maybe solder a connector that you can just plug in the the fuse, just an idea but I do see them soldered all the time maybe they pop after a certain amount of time with whatever temp they are rated perhaps try seeing how long it takes for them to pop with a soldering iron. 4 dollars?!!!!! Wow. Must be made with unobtanium. Again Great vid. Pls keep them coming👍👍 I'll see if I can drop some bucks off at your patreon.
with the not resetable fuses. DO it like its in Laptop Batteries, solter them to short nickel strips and than spot weld this nickel to the cells and solder on the busbar.
The thermal fuse is of no use unless it is controlling something. IE control system. Otherwise it's just an expansive fuse.
Love these vids mate
Thanks!
Curious on the fuses that didnt blow, did they have a different resistance between the cell and busbar? Also is it worth pulling the cells that didn't blow for a quick capacity test to see if they are lower capacity than advertised? Perhaps what once was 2200mha is now 1400 (ie not enough current to blow)?
I see the point here where the need for 1Amp fast blow fuses to work at very least amperage.
I would like to live close to you so I can get help building my diy battery
I don't help others in person sorry :P so living near won't help..
even those 5 fuses did not blow up. that pack voltage is only around 1v, that enough for BMS to detect sth wrong n cut off;
Great video man. Very informative.
I also want to be in same business.
This is not a business to be in to pay bills.
@@kiwiscanwifi In India a person like me can work on these things for around 16 hour a day. So, you get the idea.
Sir.
Best of luck
@@HBPowerwall thank you sir.
@@HBPowerwall I have been watching your video since a long time, I appreciate your work.
I am a bit of a battery virgin, so excuse my uninformed question, but if a fuse level pack experiences an actual in use dead short that blows most of the fuses and the problem is not noticed, is there a chance that the charge device (whatever the device may be) will continue to try to charge the few cells left to destruction or will the remaining fuses finally blow and/or will the charge device detect the problem and shut down the charge.
In other words, if the pack in use and not noticed in the short condition, will the remaining fuses eventually blow or will the cells continue to cook until something happens until they are completely destroyed?
For those power supplies you set volts then join wires together and set amps
Thank-You for that info
Is it possible the pos. Side of the cell could be damaged from all the soldering??
Hell yes!
also take a look ate the back fuse wiring
75C is probably extremely too late to protect an 18650 from blowing up. Also this just goes to show that everything can look well connected but it might not be. so check your cell connections!
Have you thought of using solid state self resetting fuses?
Post an URL to the component you recommend
Many types available. here is one rated at 1.1A 60V. Try searching in Digikey or Mouser for PTC Resettable Fuses.
www.digikey.com/en/products/detail/bel-fuse-inc/0ZRP0110FF1E/9468256
Didn't you used to have more videos on this channel? I was looking for a one where you installed a safty container with your wife.. but couldn't find it?! also the ones on the mini conversation Im looking for.. Maybe I got you confused with some other joey but I believe it was you
That`s the car of Mr Bean right there !
That'll be Mrs Bean thank you lol Hers not his :P
So has his fire basically come down to the over rated fuse wire? was he expecting each cell to output 8A under load for his use case, was he expecting to much? or was it just a mistake and would a 2amp fuse blow when a cell turned into a heater?
@Anthony Barrett
- You will never know what actually caused he fire. You can makes guesses. a) maybe it was a "heater" cell ... b) maybe it was bad "fuse wire(s)" ... c) maybe it was poor construction ( caused a short ) ... d) All of the above ... e) some of the above ... f) none of the above ...
@Repairman Even with a 2 Amp Glass Fuse, a "heater" cell can still burst in to flames. So, was the 7 Amp Fuse really the source of this problem, or just another problem?
Low temperature soldering/brazing rods for the thermal fuses just an idea
hopfully baterry hookup nickel fuses are reliable then as nothing else seems to be very safe
That test is next well soon, i have other commitments to deal with first. Unless for some weird reason I make a million bucks from TH-cam this month that is..
my opinion those fuse did not blow up same time because some battery are different internal resistance so i believe if you use new battery all same chemistry like IMR if you mixed between them lime IMR then NCR so some fuse will not blow up some will so if you try new batter match all things i said like same chemistry same cycle same internal resistance
I would agree
Fuck those dam fuses on batteries, they break too dam easy, inconsistent as hell.
Spot weld the fuse wire. Instead of solder.
That's all well and good BUT IT DON"T WORK lol
I don't get it. Fuses are a safety device, but soldering them, especially to the center of the cell, damages the cell. So you're damaging the cell to install a safety device in case the cell fails, increasing the likeliness that the cell fails.
If we're going to copy the tesla style pack and use fuses, why not include other knowledge from those same packs. They use vibration to weld the fuses on. Of course a DIY pack builder doesn't have access to that tech, but we have access to plenty of cheap DIY spot welders that would minimize heat to the cell.
We know heat to the center of the terminal is extremely damaging to the cell, to the point where factory made packs use nickel strips that have the center of the cell removed to help stop any heat from getting there. So why would we ever apply our connections to the center of the cell?
What are we doing, if anything, for thermal management?
What are we doing, if anything, for a dustproof, fireproof enclosure?
If we're just cherry-picking the easy safety precautions to follow and then ignoring the other ones, that isn't safety, that's theater.
Have you considered cutting small nickel tabs, and soldering the fuse to the tab, and then spot welding the tab to the cell? Time consuming, but it allows you to basically use the same method you've used here without putting a glob of solder in the center of the terminal and while minimizing heat to the cell.
All these tests in past few video stemmed from how someone did it.. now how we should do it moving forward - however I'm sure someone will move forward different from this playing I've been dong.
Dude, when a cell fails, it's going to fail regardless of whether a fuse is present or not. The best that the fuse can do is protect the cell from external short circuits.
These glass fuses are great for this purpose and they are reliable!
The best way to go would be to purchase brand new protected 3500mah batteries, they are very well protected and your battery bank will be super neat and tidy but it's gonna cost ya!
@@PeterMilanovski Yes, which is why I'm pointing out that the fuse is only 1 part of the safety picture, and I don't get the point of using a fuse but not taking very basic precautions like not soldering or at the very least keeping your connections away from center.
@@HBPowerwall there's not enough videos on this topic and if there was, they are to short, either they are deliberately made short or stuff gets left out onto the cutting room floor...
Yeah there's always someone who complaining about video length, I know because I was one of those people, well I didn't complain in the comments but I avoided the channel only to re find it again at a later date and realized what I had missed out on! I went right through the whole channel and watched every single video, they run for at least one hour minimum! I have seen others complaining about video length but it's their loss as it was mine before them! Now I click like even before I watched the latest video!
What you are doing here is unique, going through the process of finding the best method of protection is fascinating viewing, I know that I'm not board! LoL I could easily watch you test different ideas for 11 hours straight let alone 11 minutes, besides, blowing up fuses is fun, I know, have done it may time's both deliberately and accidentally...
I don't know if my suggestion is worthy of a mention but it just came to me as I was typing this out,
Another possibility might be PTC fuse, it looks like a ceramic disc capacitor, you would have to shrink wrap it's legs but once done, you can fold it over and place it in between the batteries, heat makes them trip faster as does excessive current! And they are self resetting! So long as they don't get damaged.... I use them on speakers, when they trip, it sounds like someone has just turned down the volume! They stay tripped until the volume is turned down or short circuit removed....
I'm not sure how they would go in this application, they come in different wattage ratings and you can parallel or series them to get the desired outcome, they should be available from jaycar, I know that I have got some form there age's ago but since discovered that if I'm prepared to wait, I can get 10 for the price of one from jaycar over on eBay!.. actually I believe that they are called PTC resistor's, even though they are resettable fuses...
@@caramelzappa I get what you are saying about soldering the cells, I personally haven't come across any real information regarding the heat from a soldering iron, let alone what it does to a cell if it's done more than once... I know that people do it, I haven't myself, I purchased those plastic spring loaded cell holder's from eBay, they are cheap, quick to pull out a cell and I can have a single cell protection PCB board for every cell underneath it and I can keep all the cells tied in with one neat zip tie... But my method means that I have to charge all the cells at 4.2V! Even if the output from the protection PCBs are wired up in series... The output only needs one fuse! As the PCBs cover everything else, over and under voltage! Short circuit... And because they are in this configuration, they are naturally balanced! Each PCB will stop charging it's cell when it's full while having no effect on the others!
The PCBs are really cheap and they stay with the battery holder meaning that you don't have to use expensive protected cells... Well that's how I have mine set up...
I guess that there's hundreds of other ways to do it, the heater cells are a worry, my cell holder's are plastic! But I'm only using new 3500mah cells and I'm only pulling 500ma from each! Although a thermal camera is next on my list of things to get!
Very interesting!
Glass fusses are way to go ....i have little bit larger packs with glass fuses and no issues at all ....
How do you know that you have "... no issues at ..." ??? Did you short out the pack? Do you have video showing that every fuse, in the pack, will actually blow?
1 because i have tested every cell 3times
2 this batterys have only bin tested once....
3 thermal issues have some parallel issues like self discharging or high internal resistance .....by full and when they are empty...
4 equipment that u use shuld not be mass produced 20$ diagnose Bt-c3100 is inacurate ....
First charge of salvage batterys shuld not be more than 0.15A ...
Yes is long first charge but in this stage u get first heaters because batterys are charging long time ....time of first charge shuld also tell u someting is not ok...
If batt. is ok no heat will build up ect ...
5 by testing capacity with 0.5A ...discharging....no heating up
SkyRC mc3000 is great option to use ...
Calibrated ....
6 waiting time 5-7days ....first charge to exacly 4.2v then put batterys to rest... after5-7days measure the voltage ..if is bellow 4.17v is no god for powerwall
7 pack asembly .....asemble the pack...
Charge to 4.2v and put to resting for 5-7days again if is below 4.17v charge pack again and serch for heaters thermal gun ect...
Then disconect all batterys on the one side ....i do on the neg because on pos i have glass fuses ...wait 5-7days and measure every cell replace the cells that are no god....asemble the pack charge to 4.2v and repeat the procedure until u get 4.2v on the whole pack after week of resting....
7 measure capaciti of the whole pack with ZPB30A1 V2.8 my device....
I use 6packs/135Ah in parallel and 14 in series
Mach capacity batterys thogether one 2000mA and above
Second 1900mA
3 1800mA and so on down to 1300mA
so every 1s group have 2000 and above have 1900 have 1800 an so on ...
Usebal capacity is 600Ah/52v ....active balancing is required 50-90€ with display and constant balancing ....
Max draw is 100A long term...also charging after 3.4v i consider cells as empty and 4.04 are full .....and i get my 600ah wit on issues...
Man i have tested cells like 3years and look all videos hb powerwall and others also make mistakes along the way 3times have taken all packs a part and it still was not perfect ...then u take paper pencil and wrote every mistake i have made and look also other ...adopt god things....
Hb is cool guy ....but i think his packs are simply too large ....
That burning pack was just extemly abused ...
And balancer it must be active because are old batteries at least 5A shifting current capabily ....mixed batteries act different at 3.3v and 3.8v curve of discharge is not linear and every so small disadvantage could active balancer make to disspeare....
it have to be constant balancing.
even now if i go look battery volages i see that is shifting current around ...
Now days good active balancers cost 80-90€ with display or monitoing capable ....
My batterys lie on the same spot more than 2 years now without any intervention...
On sunny days i charge them with over 100A constantly no isses....
For now ....
So what do you walk away with?
No loss of life, learned a bunch, started a conversation & got to play...
Cheap red 17$ spot welder from AliExpress or eBay would do a great job welding fuses to the cells. Not sure about the bus bar.
Yeh for the first three welds - no thank-you :(
@@HBPowerwall I completed over a thousand successful welds between relatively thick nickel tabs and it does the job great. No complaints other than the device heats up a bit. I highly recommend getting one if you need to weld but can't justify the €200+ for a bigger unit.
I added solder to the device I got and it helped me get a lot of welding done quickly.
They would for sure be good value for small projects - can't go past a real one like the Kweld if you want 100,000 welds and counting.
@@HBPowerwall I would say they are capable for most projects most people do. My point is they certainly do their job while costing almost nothing compared to other units. Definitely a worthwhile investment if you need a few hundred to a few thousand welds.
Glass fuses are far better then just having a fuse wire in free air. This is a reason why they are encapsulated as well. As it keeps the fuse wire in a stable environments and allows it to blow as a set amps. The fuse wire in mid air has so many variables it’s not ideal at all
Fuses do not blow at a "set amps". They blow after some MAX TIME has elapsed, with a given amount of amps, per their spec sheet ...
Fun times!😎💥🤘
The thermal fuses are no better than the glass fuses in this situation.
The cells that are not blowing the fuse have a problem of some kind and are not able to provide the energy to blow the fuse. Probably the IR is higher and the meter you use may not be able to discern it as I don't know how it measures it I can't comment.
1. If you take those cells out and test them by shorting them with thicker wire and your clamp meter measuring the current I think you will see they can not provide the current.
2. Do the same with a cell that blew the fuse and you will see a big difference.
3. The ones that do not blow the fuse if left in a short condition do they over heat?
also the fuse is to high Resistance if there is 1V dropping on each one, double fused means 2v over the fuses
@@flipschwipp6572 The last test was with 4V and 1 fuse and 5 fuses did not blow.
Really seems to me like the cells that didn't blow their fuses just aren't capable of providing the amps needed, and are quite probably faulty.
Maybe pull some from the pack and using a current monitor see how much current passes through a wire dead shorting the cell.
Or maybe High Resistance from a cold solder joint?
2amp blow, we'll call them 2 amp fuses! 🤔🤣
well invoice said 2amp so close enough right?
1.5 Amp or .5 Amp maybe?
2amp as it turns out
Its important to fuse each side of batteries?
Some do, I think it adds another point of weakness and resistance.
@@HBPowerwall then i can use 0,15nickel in negative side spot welded, and soldere glass fuses on positive side?
@@HBPowerwall one more question 😁. In normal use have you blown fuse in pack?
I think sanyo did it! Either sanyo or it was the squirrels! Ha-ha!
we will run with sanyo lol
I would put 1a fuses and call a day why u not did that? Why?
Because it is 100's of extra failure points, looked ugly, is more expensive, and doesn't add that much more safety in this application. Already use fuse wire rated at about 3-5 amps for years, and never had one fail.. Fuses are for holy fuck moments - massive dead short of some description. These or even my current fuses still don't blow when a cell is faulty and self-discharging and heating up.
Dit the wire coase the fire?
Edit fuse wire
No poor maintance did ..
I have 1400 glass fuses @ 2 amp. I think i'll dip them in Dr Pepper first
I should try that with my 900fps camera
those glass fuses are most likely 1A, my 2A fuses blow at 3.16A
So what's the idea behind the fuses?
I get that it's a protection but watching these last few videos it seems that the dodgey cells don't have enough energy to blow the fuse, whereas the better cells blow it right away.
Also, the testing you're doing is simulating an external dead short. Wouldn't a fuse on the cell be better?
If the pack had an internal failure, then would a single battery actually be over supplying the current that makes it fail?
to understand the fuses, my best guess would be to test batteries in various conditions (full/mid/end of life) with a load and fuse to see how it reacts.
The more I think about it, the more I feel the fuses add nothing more than a false sense of security - sorry bro...
Thermistor maybe?
I think you're not really doing this video justice unless you measure the current those (individual) cells are delivering on a dead short. Just remove the cells that did not blow and put you ammeter in line with the fuse and then short it out.
I think what you'll find is that although these cells show full voltage when charged, they are likely unable to deliver more than an amp or so which means they will never be able to blow the fuse.
I think what your highlighting here is one of the risks taken when using used cells from hundreds or thousands of different sources, all of different ages and all with different usage histories and then putting them together in a pack to act as one cell. Obviously even with the best care taken in testing and selecting cells, you really cannot determine age and you are bound to run into really all sorts of weird types of failure.
I think if you do this test again with brand new cells, you will find that every single fuse blows as expected. Which would be a really good test to highlight the differences in behavior for your viewers!
Great job with these videos mate!