Paralleling two 48V battery banks. A self-balancing system. Part 3
ฝัง
- เผยแพร่เมื่อ 7 มี.ค. 2022
- We finally connect the new battery bank to the main bus bar system and... turn it on. Before, I checked all the connections, voltages and polarities again. And again. We want to avoid a big bank here, right?!
Straight away after connecting, we can see how the two battery banks balance themselves. Even with the same voltage, the battery bank with the higher state of charge takes less current from the charger as expected.
I also try to make a battery cover out of some clear PVC sheet as the final touch and protection of the battery inside the shelf.
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DISCLAIMER
By watching the video, you agree:
All electrical work must be carried out as per your local laws, rules and regulations. Installations and setups shown in my videos are for test and demonstration purposes only and may not satisfy regulatory requirements. Installation are temporary, for the above purpose and for making these videos. Most electrical work is not for DIY purpose and must be conducted by a trained and qualified person. Please always check your local regulations!
Any liability for conducting your own work, in particular, any consequential damages arising therefrom, shall be excluded. - วิทยาศาสตร์และเทคโนโลยี
With the high volatility of energy around the world at the moment, I am sure more and more people will invest and love your videos as much as we do.
That worries me, with more people jumping on board we may see LFP prices go up with the demand.
@@gavinnoname1424 I just got noticed from someone providing EVE cells that supplier from china already decided to go higher the the price per cell. Not sure, but probably indeed related to the demand and the situation in eastern europe.
Also, a lot of EV manufacturers are now using LFP batteries in their vehicles. Demand is surely a lot higher than production. It is still worth doing!
@@igorybema indeed in the Netherlands it was noted the price per cell increased by €20 already.
Im in South Africa, the power utility cant supply the demand due to corruption within and no political will to eradicate it, hence we have load-shedding in stages. Today we are on stage 6 so that means 2 x 4 hour and a 2.5 hour power cut over a 24 hour period. Read in the news that Nersa the energy regulator is now planning on stage 16 cuts so just a matter of time before we hit a total blackout. You should see how the prices of solar have skyrocketed in the last 2 years. More than 200%
Love the blue stuff mounted above the batteries ❤
Your balancer testing videos were my gateway to finally moving forward with my own solar project.
Absolutely great work Andy. I have been watching all your videos and learnt SO MUCH from your hundreds of hours of tinkering, testing and hard work. You have given me the confidence to start my own battery project. Thank you!
Thank you David. Great, that's what I want to hear and inspiring other to do their own projects. I'm sure you can do it!
I follow you with a lot of interest and you are a very nice and positive person. Congratulations on the professional work. I wish you good luck!
Thank you vey much for your kind words!
Thankyou for making videos I automatically smash the like button on before even watching. Beside the relevant (to me) content, your attitude and smile are the reason for my comment.
You're the best! Thank you
Love this battery bank build ! My banks are 24 PCS 3.2v 280Ah & I’ve got 6 PCS 3.2v 310Ah , battery combiner 6-50v , 3 bank & alternator charging 120A Model BI-120A1B3 , inverters 5KVA 230v Inverter charge controller 48v - the 230v is the L1 is 115v & the Neutral is a hot line of 115v Total Amperage is 88A , my house only has 1 - 220v which is the central AC literally my house could run on 1 phase of 115v in in the US , I’m mainly only using for battery back-up ! “ if they throw the switch ! Fantastic video
Thank you.
What a great job, 1st class workmanship. Now the Teslander will only be feed sunshine.
Thanks Dick. Not with all the clouds at the moment. I definitely need to increase production in the following cooler months.
Now comes Andy's New Lessons:
- Observing how more than one battery pack will Charge in combo and teh interaction there.
- Observing the Balancing between cells & the packs
- Experiencing multi-pack discharges both Hi & Lo Amperage and that changes things.
Things are just about to get Real Interesting and new Lessons Learned will be shared without a doubt.
Are there surprises coming ? Yes Indeed and some WILL be a surprise.
One lesson to be learned later on as this progresses... Is WHY the battery packs should be configured to be able to operate as the "Last Man Standing" . This is to facilitate functional capability regardless of how many packs in the bank are "live" and provides Fall-Back security.. Any single pack within a bank should be capable of supporting the system as a standalone.
Very good points and yes all of these and many more will be explored. There is a lot to learn from such a setup.
@@OffGridGarageAustralia You can bet your bippy that the Adventure is just about to really begin. Multi-Packs in a bank are always interesting, especially with different cells (grades) and even more when different sized cells packs get nto it. 280AH & 304AH not a biggy but 200AH & 300AH and things start to really get fun. That's likely something that someone else will explore.
@@stephsoltesz6731 by last man standing you mean each battery pack with its own bms? is there a good video on this?
@@joaosidonio7562 He means should all batteries but one shut down, any one of them should be able to support the system on its own.
@@joaosidonio7562 yes there is a vid on this here at Andy’s ‘Off Grid GARAGE”, check his other vids, Cheers
Great progress, nice the battery banks will take their part of the load, DC is nice and understandable. Time for a SPAT
Thanks Edward. I had a SPAT or two the other day and just looked at this monster, I created, the PowerWal and battery shelf. What a project!
Can't get enough of your channel. There's still a bit left on this project (getting the other 2 batteries loaded in the shelf) so I have at least a few more videos to look forward to.
Thanks. A bit left? We have just started! Once the batteries are all in place, the whole fun begins and we will test the heck out of all the equipment out there. We have the ideal test bench for all kind of tests. Tons of video to come!
@@OffGridGarageAustralia Glad to hear it. You are my favorite TH-camr - great informative content that is made even better by your bits of humor and clever editing.
Great vid !!!
Your 18650 jumper pack to start the BMS is exactly what I did.
It works and I'm not too concerned as the BMS will stay on all the time. I only have to do it for maintenance (and all my future testing, I'm afraid)
The laughter of success, hahaha. I like your job Andy
Thanks 👍
Love the battery cover
I'm so glad it worked out and I didn't f* it up. It would be in the video then 😂
Heisenberg principle👌
Looking good.
Excellent ! j'aime beaucoup.🤩
Oh my I’m eager for your next video about the Jk annomoly/problem! I just finished installing mine and noticing similar behavior.
Video is uploaded (using the guest wifi 😉).
I have even more problems with the new battery 🤷♂️
This is very well done
Thank you!
Just a little bit late.....I just ordered at HankzorStore two JK bms's. Without display.....Almost ready to parallel my three bank together! Andy, keep on going with your very instructional videos!
Thanks Victor, much appreciated. The display is not really needed as the BMS will not turn off itself unless there is a major fault or you disconnect it from the main battery.
@@OffGridGarageAustralia I wish I had known the display model does not require that stupid jump start, I would've ordered in instead!
Hi great work
This guy has knowledge and talent for videography. But we need to know about Australian specific, what we can do, what we cant do . Pretty hard to find this information. Anyway Great video.
Thanks a lot for your feedback.
Tolle Arbeit. 👍
Vielen Dank!
Great stuff again. I'm excited to have received my 16 304Ah LiFePO4 batteries from Amy this week too 👍
Nice! that's exciting. Mine are still on the ship somewhere in the Pacific for another week before they arrive in Sydney.
@@OffGridGarageAustralia I ordered 4x 280Ah to Sweden. They have only these one n EU warehouse... I gave your name to Amy.
Like the wiring
Thanks. I try to keep is as tidy as possible.
The battery cover was a great idea,like the temp sensor locations
Oh, you watched until the end... great! The temp sensor location just happened to be there. I'm keen to see how the breaker temperature goes as they are heating up quite a bit when pulling full power.
@@OffGridGarageAustralia would make a good video
@@MrSqueegey It will be in one of the next ones ;)
Looking real good Andy, almost done, now you just have to fix cell 7 (2 SPATS) on battery 1.0 and put battery 1.0 into battery 2.0 and then start on battery 3.0.!!!! Don't remember the reason of the voltage fluctuation problem but I am sure you will find it. Keep safe and charged.
Thanks Glen. Yeah, I have more cells coming in for the shelf. The old battery will stay offline for a while for testing and repair.
good mate it will self balancing.
Congratulations, I would love to see all your conservative settings for your bms and your mppt.thanks for all your videos.
Thanks Chris. I will have them on my website soon. It's a work in progress for a while to get all the information.
Guten Morgen aus Kaiserslautern
Ja, Moin! 🙋♂️
looking good o
The fluctuations are due to the inverter draw. It's not a constant, more a wave/pulse shape, and the BMS doesn't have a long enough integration time to average the result like a multi-meter does (RMS). The BMS samples the voltage over a shunt resistor periodically, but does not do averaging over time. You can actually see the inverter draw very well with a scope. Is it a problem? Not really, since it is still correct and if you would take an average over time you would get the RMS value - you can see this easily if you graph the BMS data in Grafana for example through the RS485 port.
Ahhh, great explanation as always. Thank you. That makes totally sense! I have an oscilloscope here so can make this visible. So with a pure 48V resistive load this should be far more stable, right? I just don't have one apart from inverters 🤷♂️
@@OffGridGarageAustralia Yes, a pure resistive load would give a stable reading. Hook up some incandescent light bulbs for example.
Correction: replace RMS with average. RMS is typically for sine waves only.... It was late when I wrote that comment :)
highly informative, inspiring and motivational… not too mention impactful (on my wallet)
… your paranoia is catchy …. i just purchased an IR camera, a digital torque wrench adaptor, and a sheet of PVC ! i already have the heat gun .. haha
Hahaha, great, thank you. That's good equipment to check on your battery. All the best bending the plastic. It's not too hard actually.
Ottimo lavoro amico mio, BMS Smart risponde bene 👍
Aeh, yes, thank you😉
I am watching you get excited with the sound of B52 roaring over head - how crazy is this world
Looking good 👍.😜😜
Thanks 👍
Thumbs up and still subscribed!
Bravoooooooooo 👏 👏 👏 👏
Niiiiceeeee!
nice nice nice andy..
going from : " less than ideal" to "pretty much ideal" rapidly
You just have to find the right way and solution 😉
Hello my dear, I'm from Brazil. I consider your channel one of the best in the world in renewable energy. You serve as a great inspiration for me and many people in Brazil. I would like to know if you assemble these lifepo4 banks for yourself or for customers? and, is there a video of you showing how batteries are discharged in your everyday life at home? Congratulations and thank you for sharing so much knowledge.
What I took away from this video? I miss my McDonalds coke cups :(
Glad to see you being super careful and double checking everything!
Yes👍🔋⚡
👍
What a curious coincidence that's the same password as I have on my luggage.
Check active balancing settings Andy. This was causing voltage sense fluctuations in a previous video.
The balancer is off here...
Estoy probando busbars de aluminio y me gustan mas que los otros
guy- Thank you.w ell ! ;))
Heya, some AGB led light inside would be nice if you will make yhe front panel transparant too
My guess is your busbar connections to the terminals are not perfect, resulting in the voltage fluctuations.
I read good things aboud MG chemicals 8463 silver conductive grease on the solar forum for this.
Looking forward to your new video to see what the root cause us.
Good job on your build. Love it. Learned a lot:-)
Thanks Peter. Yeah, there are a lot of different grease out there. You ask 10 people and have probably 8 different answers. You can only try...
Nice setup Andy mine is the same only a zillion times smaller (24v90ah), well not the same but only what I need, I need clouds for my battery's will kick in, I'm not sure what i would do with 3x48vx280ah, but very nice setup, I payed
I'm preparing to supply power for the whole house with this system at some stage, hence I plan a bit bigger right now. I also charge my Tesla form this battery so need the capacity as I'm not at home during the day when the sun shines.
As with your example, you can get a way cheaper setup and equipment than I bought. For me it is a big hobby. Others have boats or go on holidays, spending their money elsewhere...
Second 18:02 = "ha ha ha haaa!!" ... mission accomplished :p LOL
I needed to demonstrate the safety this plastic adds to the build 😂
I think that the voltage fluctuation seen at the BMS comes from the little balance fuses' resistance. When the BMS starts balancing there is a significant voltage drop on the fuses, hence the fluctuating voltage you see. Balancing switches on and off rapidly and you get confusing readings. I would not put wires on the BMS leads. If a fuse blows, usually the BMS reads a ghost voltage on that lead, that can be within the set acceptable voltage window and continue charging the pack even in cases it should stop.
But the BMS does not balance at all. It just measures voltages.
Happy to see the shelf itself is live, those circuit brakes get warm 😅
Andy, are you going to use the cells in the black battery box as part of the the shelf, if not can't I releave you of them one day. New eve cells are just way out of the budget specially with my new born still in icu.
Have you decided what you will do with sealing of the bottom of the shelf? I'm still voting on expanding foam.
I have 32 more cells inbound in 2-3 weeks. They are still on the ship on their way to Sydney now. This will fil up the battery shelf and I can then take off the battery box for testing and repair.
The breakers actually don't get that warm. It looks dramatic on the FLIR but they only have around 35°C, so that's pretty normal at almost 100A.
Hope your little one comes home soon. All the best!
Hi Andy, great video, as usual. 👍👍 About temp sensor location in the main breaker, isn't there a similar hole at the upper end of the breaker? Since hot air goes upward, you know...
The breaker has several opening at the back, not sure what they are for but this one perfectly takes the temp probe.
With 3 banks installed at some stage, I don't think the breakers will get that warm ever, but yeah, I can place it in the top one, sure...
Dear sir, i want to use a two 13s6p (each 48v 15Ah) batteries which came with a bms with each of them within its packs ( total 48v 30Ah now) my question is : can i replace with it a single bms of 30Ah
Hello Andy. At the end. Do you think you will add a active balance in add to the JKBMS ? Could it work? What is the interest? How can it work together to. Alan ce the cells? It will make perturbation no?
I have not planned doing it but can for testing purposes. It will work just fine. Only keep in mind to turn on the balancer only when cell voltage is above 3.4V, better 3.45V.
Andy, another great video.
I love the bended battery cover, simple yet brilliant.
Are you able to tell me why the 'battery remaining' in the jkbms app is so far out?
In your video it shows 66% remaining while you suggested 20% (battery voltage confirms your suggestion of 20%).
Thanks Steven. The BMS needs calibration and I have to fully charge the battery first for initialisation of the BMS. Until then it guesses wild!
charge/ discharge oscillation between the 2 BMS's? i dont wanna wait next video for answer!!!!
What do you mean by that?
@@OffGridGarageAustralia thought maybe those fluctuations were due to the bms on both of the battery banks fighting each other
Hi Andy, what is your BMS suggestion for 4S 280ah? forBMS, Should i buy >200 amper for 280Ah cells (i would use 4 x LiFePo4 280Ah cells), What is your best efficient BMS suggestion (with bluetooth)?
That depends on your load, not so much on the Ah of the battery. For a 4S, I would probably go with the JBD BMS, even the balancing is not the best (but workable). Or you can go with Daly but need an active balancer to top balance from time to time.
Probably you have active balacing activated. Even JK BMS doesn't measure voltage when the exact moment of balancing, probably the "length" of battery cells' cables makes this as a little induction that makes JKBMS measures voltage fluctuations. Someone could think that it will only happend in two cells (less voltage and most voltage ones) but as all cables are joined we have induction in all of them.
Nope, balancing is off and would only kick in at 2.45V
Can you please share you setting for the JK bms. eg, your over and under voltage cut off setting. I have the same JB bms with Ev 230ah cells. Thank you
Sure will do. Stay tuned...
Hey Andy, I’ve tried to navigate your videos to get me through a lifepo4 battery upgrade from my lead acid ones. We’ve lived offgrid 7 years now. I’m looking for where you bought the switches or whatever you’re using when paralleling these two banks. I just connected my two banks today and almost filled my shorts. I just used cables directly on the battery terminals. The positive side is fine, but on both banks the cells on the negative side started bulging. The one cell has completely lost its charge. Not sure why or how the JK BMS let that happen. I have the B5A25S60P. Each BMS has 3 - 500A contactors. Not sure why it’s done this. I assume the bulging because of excess current through these 2 cells. Am I in danger of explosion? Please help!!
Very hard to help here, as I don't know your setup and you provide little information of how the cells are connected, voltage, cables sizes, why no busbars,...
After thinking about. I think it will not work to put 2 balancer on the same cable. I think you need to. Use individual cables for each no?
Why should it not work? I think you can add as man balancers as you want to the cable. I guess we will test this soon ;)
Dear Andy, I have been watching all your videos for the last six months and i find them very educative. I am not an electrical engineer but i feel alittle confortable to start a small project. I have one question, i have victron two 25.6 V batteries and 4 X12v victron batteries also. I have asked so many people if i can parrel the two batteries systems together but they have always discouraged me that Batteries have to be of the same type. I have watched this video more than four times and i think my mixed ystem can work. Any advice
Thanks for your comment. What kind of batteries are they? All lithium batteries? Some lithium, some lead acid?
You think setting the bms to 60A will prevent it from exploding? It only may protect the cells. The bms will allow any current for 2 seconds. Could be 200A of 5000A. For 2 seconds, the current will try to blow up your BMS and may succeed. I don't know if you should give people advice while not knowing exactly what you are talking about. Nice style of video's tbh, and nice that you share your findings with people.
Hello Andy,congratulations for your work.I want to tell you that a few months ago I also used two 2A JK active balancers. I also noticed exactly the same instability in the cell voltage, especially at high currents (charging or discharging).Now I use two 4A active balancers from Neey, to which I do not notice this instability. Maybe the ones from JK are more sensitive, faster to read the voltages.
Thank you Mihaita.
From what I learned, the JK BMS does not measure the average voltage over a certain time as your multimeter would do (RMS) or the NEEY balancer does. Hence measuring the voltage seems wild and inaccurate but in fact it shows the real voltage at time of measurement. The inverters will not draw a pure resistive load so have a bit of ripple on the DC side wich the JK-BMS shows but not the multimeter with its RMS reading. So, it is all good and no point of concern.
the resistors and bms wires fluctuating?
No, it's not that. I'll explain in one of the next videos...
Andy, the reason you did compass the batteries was it because of the AS3000 specs on fire resistance?
compass what?
So what was the reason for the voltage fluctuations?
In short, the JK-BMS does not measure RMS but shows the real voltage.
It'll be in one of the next videos.
The last time you had the voltage fluctuation it was due to a dodgy balance cable connection which I think yuo soldered to fix
Yes, so, that could not be it any more in this case... I'll explain soon 😉
Great video Andy
I thought that all bms leads have to be same length and size , is that not the case anymore ?
I cannot see the point of having them at the same length. The BMS measures voltage, right? So there is pretty much no current flowing in this process. The cable length should not be critical at all for any BMS.
Can you send me the diagram I want to connect two 48v battery into jk BMS
Just discovered your channel. What a treat. You are doing the experiments I've been thinking about. Have you experimented with a mix of LiFe and AGM ? Best of both worlds ? I have one 200 amp LiFe in an old van I bought and two 100 amp AGMs from and old caravan, both take a good charge of about 13.5 volts. Can't afford to stuff it up lol. Cheers.
Thank you Brian and welcome to the channel. Exactly what I thought as well as I could not find answers to many questions about LFP batteries. So I started doing all these experiments and tests.
Why do you say 'the best of both worlds'. Why is it good to have AMG batteries in the mix? I think LFP is superior over AGM or any other lead acid in every way.
@@OffGridGarageAustralia Thanks for your reply. I have two AMGs, 100 amp from an old van, batteries hardly used, and a 200 amp LiFe in a Crafter I just aquired, so I looked to see if there was a way of having a benefit from both, but just found one example from a person with a long history of boating. He said basically the more rapid response from the AMGs supplement the length is discharge from the LiFe.
I thought there would be more info...and you seem like a person who would make sense of such posibilities...and perhaps a good experiment if you dont know.
Cheers...
@@bigfletch8 You're not talking about Clark from Emily's and Clark's adventure? I don't agree with him in many points.
AGM is the slower response battery due it its far higher internal resistance. So having them in parallel, the LFP will do all the work first until the AGM kicks in to supply power as well.
The problem with such a setup is, that you should only use a maximum of 50% of the AGM's capacity to not damage them too much. So you need to have something in place to disconnect them at some point and only use the LFPs for the lower part of you state of charge. I think Clark has developed such a BMS which can work with both chemistries and does something like this.
If you have the batteries and want to use them, I mean why not. An alternative could be to sell them and buy some more LFPs instead.
I can do some testing as I ahve some smaller AGMS and also smaller LFPs so could set something up and see how it could work. Would be in deed interesting and a lot to learn from. I'll add this to my list of videos...
@@OffGridGarageAustralia Thanks again...Yes..thats him....Given only he has tackled that topic, it would likely be a big boon for your channel. Also there may be a lot of discarded batteries which may still be of great use.....Cheers Brian..Perth Australia. We sure have plenty of source energy here hehehe..
Don’t Love the smell of burning cable in the morning
I don't love it at all. At least not in my setup 😂
Somewhere I must have missed why you are not keeping the batteries under compression?
Because its not necessary. I'll explain (again) in one of the next videos.
I think a total energy (kWh pulled from the solar battery) comparison test where the car charges at maximum rate and at minimum rate would be an interesting video. I'm quite curious to see how much of an influence the charge speed/ current has on the total efficiëncy when charging the car battery for the same amount (0 to 100% SOC for example) at minimum speed and maximum speed. I would imagine that for solar, charging at a lower speed would be beneficial for efficiëncy due to the lower overall current and less losses.
Just an idea! Cheers from Belgium!
I like that idea. For power supplies (ad/dc) 50% of max load are deemed most efficient. I am curios if this holds true for inverters and also if one can set both the phoenix and multi to 50%
@@HolgerNestmann Ah just learned something new about the power supplies, thanks! I would imagine that for the solar car charging there would also be a "Maximum Power Point" which could be reached by adjusting the charge speed, where the total setup runs the most efficiënt.
That's the next one coming. How did you know? 😉
@@OffGridGarageAustralia Great minds think alike I guess ;))
@@3dprint-tech787 that's why we are all here. It's all connected 😉
Hey Andy, just looking at my setup. I am planning 4x 16S setup, similar to yours. Looking at JK bms, and it has CAN, so could talk to Venus. But as you have 3 and I have 4 I reckon the Venus won’t be able to deal with 3 or 4 bms, so the shunt plays a role in the Venus monitoring total state of charge and the bms just manages its own bank.
I assume you are putting in 3 or 4 bms, 1 for each bank?
Yes, I' will use one BMS for each bank, not sure if I stick with the JK BMS or test some others as well.
What would be the benefit of having the BMS talking to the Victron system? To slow down or even stop charging if one cell gets too high? I really don't see a benefit of that. Each BMS will handle its bank individually and if you don't charge to 3.6V all the time, there is enough headroom for the cells to not trigger the OVD (if the BMS can handle the balancing).
The driver for reading the BMS and send the data to Victron can handle only one BMS at the moment. The guy who is programming this is working on a new version which can read multiple banks though.
The jk won't talk to victron just bcoz it has CAN support. In fact it is not supported bcoz it is not victron CAN protocole at all. At the other hand the rs485 version is supported since someone created the driver for venusos.
Can you do a jk 8s video
Hi Andy,
as you are using the victron system (i recall, you habe a RPi Verion as GX-device?) , how do you consider to connect the BMS to the GX device?
In a victron environment this is done via a bus connection. Do you consider connecting your batterie bank to the Raspy by (what? USB?)
I have seen rs485/bus hats for the raspi.. but nothing found as to how this interconects with a BMS (protocoll?, see victron battery compatibility list !)
Or do you just not care?
I am curious to see how you are going to balance your system, meaning capacity-vise.... large batteries, charging capacity SOLAR and consumption...
do you see the risk of batteries permanently swapping between low cutoff and low resume-... never getting full charged agian?
stay charged!
greeeting from the odenwald.
Michael-
Hi Michael, there is a project from a guy called Kevin on Github which does all the programming for the Venus OS, both Pi and GX devices. He also creates the driver for the USB-RS485 adapter which can display your BMS stats on the VenusOS.
I am very interested in his projects and follow him along for a while but just haven't found the time to do it as my priorities were to finalise the shelf first.
I thought about it for a while and asked myself what the benefit is to have these information in VenusOS? Sure, we could potentially slow down or even stop charging if one cell gets out of balance and peaks at a higher voltage, but is this really necessary? I charge to 3.45V only so have plenty of headroom before I hit 3.65V and BMS would shut off. The JK-BMS has an excellent active balancer and should be able to cope with such a difference and balance the pack out before it gets too high.
So, at the moment it seems like a feature with a lower priority as I cannot see any benefit of this. What would that be?
I wonder if the voltage fluctuations can be caused by EMI. There can be some interference coupled to sense leads from active balancing current or some other sources. On probably unrelated topic, I'm not a big fan of the DIYed double screw terminals for main battery leads even though they look cool. By using only one screw and sandwiching the battery lead between the two BMS leads you could drop the contact resistance to less than half of the current value.
It's because active balancing is generating current flow on the sensor leads and making the voltage fluctuate on the sensors. This was discovered in a previous video. Change the active balancing settings like you did before Andy! 👍👍😀
@@davidadams3669 I assumed the BMS would be smart enough, not to measure the voltage of a cell it is currently balancing. I was thinkin that when the long sense leads are coiled together there could be external fields that could induce noise to the measurement signal. Now that I think about it, if each sense lead are close together (twisted) with the leads of the next cell it should work as a balanced cable and the interference should cancel out. I think more likely reason for fluctuation is current ripple from inverter or other loads. There should be low-pass filter in the voltage sensing that does not seem to do it's job too well in that case. I'm sure Andy will let us know in the next video :)
You're both wrong ;)
The JK-BMS does not measure voltage with RMS but shows the real voltage at the time of measurement. That's all I'll explain this soon again.
It will not balance at the same time when measuring the voltage. Also, balancing starts at 3.45V, not below.
@@OffGridGarageAustralia Good to know the BMS knows how to do balancing afterall :). The inverter and other loads can cause ripple currents that will cause the cell voltages jump up and down because of internal resistances. If there is high frequency noise in the measurement signal it is not possible to get reliable voltage readings from individual samples and only software tricks. There should be an analog low-pass filter before the ADC with cutoff frequency much lower than half of the sampling rate to prevent aliasing. I don't know if the sampling frequency of the JK-BMS is specified somewhere. It can be much higher than the update rate of the display and the measurements used internally by the BMS are reliable, or not. Looking forward on the next video!
Hi Andy, my mentor can you share all the JK BMS settings for these batteries? Please
I sure can. They will be soon on my website together with the settings of all my other equipment.
@@OffGridGarageAustralia Thank you Andy very much
Hey Andy are you going to install a external HDMI monitor off the Raspi? I have done just that, just a matter of turning the headless mode off in the Venus soft.
Also are you going to install GUI mods to the Venus OS, has some nice custom BMS software as well as the shutdown monitor mod already preinstalled in the package and a heap of other nice customizable stuff for the home screen icons...
Yes, I will look into this, I've seen some mods online and they look really cool! There is still so much to do and to explore, I'm not sure if one life is enough to catch this all on video. I need to do this fulltime!
@@OffGridGarageAustralia yes it’s a rabbit hole that’s for sure. I’m fully offgrid here in south Australia.
Andy is it possible that the length of the balence leads should all be the same, I did what you did and cut and laced my leads to length. I'm now worried that due to the leads not being the same length they will introduce errors due to different resistance in each lead? Any ideas. 😉👍👍
It should not make a difference at all. Voltage measurement is without current (ok, some micro amps maybe), so no voltage drop.
@@OffGridGarageAustralia Thanks it helps to keep the installation tidy.
Ps have you seen digital mermaid, you have female competition not on your level of course. 😊
@@hunter00047 of course I've seen her. I promoted her channel here on mine a while back. I'm in contact with her. She's got a Tesla too now. And a boat obviously...
Andy i need a quick vodeo for how to repair a stripped out battery hole on the eve batts. lets be honest they screw some up some times. it looked normal but it just kept spinning. how do i fix it?
i can't be the only one to have this problem?
Video is coming very soon. The fix is easier than you think.
@@OffGridGarageAustralia so glad cause i don't need a fire. lol and don't want to stop using the batt i made. i love it!
@@brian1395 No problem, I have some terminals to repair as well, so that works for both of us then 😉
How thick is that plexiglass ?
3mm, I believe.
I'm a little surprised, will you use the battery unpressed or change that in the future?
I'm not compressing the cells. It's not necessary.
@@OffGridGarageAustralia Ok, thanks for the quick reply. I have always read so far that this increases the durability, because not so much mechanical stress is on the individual contacts, which arises during charging and discharging.
@@DocBrown101 I have a 2mm gap in between my cells, so if they want to expand/contract, they can just do that without putting any force on the terminals.
It also depends if you pull high C-rates from your cells or rather lower amps. I'll explain this in a future video soon.
If one of the BMS balancing fuses blows, couldn't that cause damage to the BMS circuitry? Seems like a bad idea
I guess it will see a lack of voltage from that cell and trigger the lower than minimum voltage condition and shut all down
No, it won't kill the BMS. It just won't show the voltages for 2 cells, that's all.
Probably there's already been a bulging discussion about cell compression? I'm surprised there's no restraint or compression, with all the other really fine work and details, why not constrain the cells.
It's not necessary and would not make a big difference at all. If you have high c-rates, yes, in our solar environment, no. It's in the specs of the cells when you should compress. I'll do (another) video on this after the installation.
as for the red cable mount - Velcro under it
Could do!
The cover is nice but....... will heat collect under it?
What heat? The cells will not get warm. I'm driving them with less than 0.2C.
@@OffGridGarageAustralia Welll maybe something unexpected, like the "HOT terminal-busbar connections"
Do you plan to connect JK-BMS to Victron Venus? On "Victron Community Forum" there is a software dedicated for that.
The software can only handle one BMS though. What shall I do with 3 BMSs?
The guy is working on a new version to support multiple BMSs. So let's see.
I'm still not sure if there is any benefit of connecting them to the Pi 🤷♂️
@@OffGridGarageAustralia Software can handle more than one BMS - I'll try to put URL to that software in another comment - TH-cam do not like URL in the comments and comment can be deleted automatically.
Benefits - controlling and monitoring all installation from one place, even outside the house over internet through remote console? Also ESS Assistant could be used (in your case without grid it hase less sense) But... if you finish that battery shelf - what will you do? :)
One hundred and something... 😂😂😂😂
🤣
Do all the battery terminal connections really have to be torqued down instead of just by hand tight? Will it really make a difference? Seems to assume that the batteries themselves are of high quality. Also makes me feel a little anal-retentive so I think I'll skip that step. I feel like some customer asked "what torque should I use?" and the manufacturer said internally "I don't know. what sounds like a good number?" and someone said 4 Nm, and someone said "good enough", and now everyone is trying to torque down to precisely 4.000000 Nm. when 5 or 3Nm are also perfectly fine.
from experience yes it does. I have had a terminal get very hot whilst the others don't so naturally, 'let me test how tight it is' and boom, stripped threads and a 'twitchy bum moment' to re thread it. I really like the idea of the welded studs that seem to be coming out of china at the moment.
I've not used a torque adapter for my battery no.1 and it worked as well just fine. You get a feeling for it when it is tight. I messed up some of my threads though as I later checked with the torque adapter and found I had them far to tight.
Especially with these soft aluminium terminals, I would now recommend one. For everything else, it's not really necessary.
My next lot of cells will have the laser welded studs as Daniel said. You can still over-torque even them and twist the whole terminal.
Sir how we decide the torque on nut
There is any standard related to this
yes there is
+Off-Grid Garage - 290AH @48V for that shelf?
That would be the same as my Big Battery “Rhino”! I can’t quite make it through 2 days heating the Taj-Ma-Haul in 19f winter nights, for sure I’m adding a second Rhino for 580AHs. I was also thinking I may need 4 Rhinos eventually to charge the Cyber Truck when it arrives. You have experience charging your Tesla 3 from batteries and solar, I’m thinking I need the extra capacity, 1,160AHs would be a good cushion to put say 8 or 900 AH’s into it and have enough to get through a night before charging from solar again? What do you think?
It’s really annoying YT disabled tagging people…
The shelf has 280Ah at the moment with another 280Ah still in the battery box next to it. Eventually we will have 1120Ah connected on this side of the garage.
@@OffGridGarageAustralia do you know how much battery you need? I’ve heard you say the things you power and the house is separate solar-wise, but can you tie battery into the house?
@@paulcurtis5496 Need or want? 😂
I cannot use the battery power in the house right now due to the contract for the grid connected solar on my house.
At the moment, I'm more experimenting and see how far I can come. I have planned to do a lot of experimenting with these battery banks and also want to test out different BMS and balancers to show you.
@@OffGridGarageAustralia hmmm, ok, how much power do you pull from per day (from the sun and battery)? What is your PV capacity connected to your system that charges the batteries?
And, well, both
Need=
Want=
😂
I still have no balance issues with my 4X Daly' BMS's
That's what you want! Do you pull any high current from your battery? If yes, they must be very well matched.
@@OffGridGarageAustralia The average current I would pull from my batt's is 20 A per string but at max output 80A per bank or 120A x by four to get system Ampere's
Please have a look at your self-bent main battery terminals with your thermal imaging camera.
They are way thinner than your busbars, covered in heatshrink (thermal insulation) and should have incresed resistance at the bend. But it can also be that it's nothing to worry about.. but ít would be interesting nontheless
Agree. They look a bit thin to me as well.
This is not a problem. The al busbars have to be thicker to compensate for the lower conductivity of the AL vs the copper. The thinner copper bus bars should be good for 250A + anyway.
I made a video here about these busbars: th-cam.com/video/mdr5HZZRaTc/w-d-xo.html
It is not a good idea to connect both positiv together. This will change the sens voltage since it will take the supply voltage from the same line.
I was just about to write the same think. I don't think the operating current of the BMS (or the voltage drop) will be much, but there will be slight imbalance compared to other cells. Better to run two wires to the battery terminal or power for the BMS from the main battery cables with it's own fuse.
Ah, now reading Sami's comment, it makes sense.
That is not a problem at all, the power consumption of the BMS is tiny. Also, I have a 1mm cable to the cell terminals so voltage drop is minimal.
@@OffGridGarageAustralia I think the largest voltage drop comes from the fuse. I don't know what the resistance of the fuse is, but maybe something like 10-20 mOhm. Also I have no idea what the power draw of the BMS is, but if it pulls for example 5 watts, that would result in (5 W / 48 V)*0.02 Ohm = 2mV voltage drop. Maybe nothing to worry about but there are so many unknowns that I would maybe measure it to see it it could cause an issue.