Why the active balancer only works at higher voltage of your battery.
ฝัง
- เผยแพร่เมื่อ 12 ส.ค. 2021
- I'm too impatient! I had top balanced my battery pack manually again by charging and discharging individual cells. The result was OK. Will the balancer actually work at this higher voltage now and keep the cells in line?
For this test, I set the solar charge controllers to the default Victron LiFePO4 profile (3.55V/cell) and observed the capabilities of the balancer.
Hankzor active balancer:
off-grid-garage.com/battery-m...
All infos, product links and software downloads to the ZKE Tech battery testers EBC-A20 and EBC-A40L: off-grid-garage.com/measureme...
Specs of both testers:
ZKE-Tech EBC-A20 Charger and Tester:
Test Voltage: 0-30V
Test Current: 0.1-20A
Charge Voltage: 0-18V
Charge Current: 0.1-5A
ZKE-Tech EBC-A40L Charger and Tester:
Test and Charge Voltage: 0-5V
Test and Charge Current: 0.1 - 40A
Please subscribe and join me on my journey of the Off-Grid Garage!
For more information, please check out my website with links to all the batteries, materials, devices and products I have used in my videos: off-grid-garage.com
The 'buy me a beer 🍻' link is here (on the website, scroll all the way down):
off-grid-garage.com Thank you for your support!
You can also click on the Thanks button under the video to support the channel. Thank you, if you have already!
**** These are the batteries you are looking for ****
🔋➡EVE LF280 LiFePO4 cells 3.2V/280Ah: off-grid-garage.com/batteries/
🌞➡Solar, Controllers, Inverters and accessories: off-grid-garage.com/solar/
🔧➡Tools, Analysers and Testers: off-grid-garage.com/equipment/
📈➡ Battery Tests and Results: off-grid-garage.com/battery-d...
🔌➡Batteries, charger and accessories: off-grid-garage.com/batteries-3/
⚡➡Cables, Inverters and Electronics: off-grid-garage.com/electronics/
Get 5% off when buying Bluetti all-in-one Power Storage Products!
off-grid-garage.com/bluetti/
New to AliExpress? Use my referral code below to register and earn US$19 store credit. What a great start! a.aliexpress.com/_mrtR9Ux
Take a live sneak peak at the Off-Grid-Garage in the Victron VRM World:
vrm.victronenergy.com/install...
My Tesla referral code (free 1500 SuperCharger km / 1000mi for you and me)
ts.la/stefan96963 - วิทยาศาสตร์และเทคโนโลยี
I like how I keep making separate searches for things and finding different videos of yours.
Hahaha, that is great. Good to know Google is finally catching up. No need to go anywhere else 😂
Thanks so much for your videos and all your great testing. I appreciate the time and humor to add. You have saved me so much time my keeping up with all the new low cost hardware. I really love the way you present very technical topics in a simplified manner so I can understand the importance of the basics.
Great channel and content Andy.
Thank you, Evan!
In your setup you can actually solve the single relay cut off problem quite easily: you just use a big diode across the relay contacts such that the battery can be discharged via it when the relay is open but it won’t be able to charge. It will knock about a volt off but that won’t matter as lithium voltage is higher than lead acid and your gubbins won’t mind it. You will lose the low voltage disconnect however you can set that in the inverter and still be protected. I regard 12v in the lithium as discharged as it’s about 10%, the diode knocks that down to 11 so you could set inverter low voltage cutoff to 11v and that will be above the BMS cut off so it won’t cut off the charge or any of that sort of muppetry. The relay will only be open briefly for the time it takes your loads to bring the battery down to the reconnect level. I actually use 95% as the auto reconnect or a discharge current of more than a preset amount.
Try putting 3 or 4 (5 watt) 3.6V zener diodes across cell 16.
Remember Zener diodes are reverse bias. Once the diodes turn on above 3.6V, you should dump around 5 amps through them with 4 of them in parallel.
Love your channel!
We have never same chemistry, same batteries, same errors in measurement (an 0.5% of error is .... 18mV !!!, imagine error value with -0.5% and 0.5% in other cell at high voltages. Or imagine 1%), same error at every single temperature or voltage, same torques, ... it is very difficult to have same SOCs, but you are doing a good job. Too much factors, isn't it?
Thanks a lot Andy.
The solution is to charge at very high voltage (3.65) and very low amperage (less than the balancer can balance) to let the balancer make is job. For a long time. In fact unbalanced cells explain that it is difficult to measure how much the battery is charged. We measure only the 100% of the most charged cells. With other cells perhaps far from being full.
Balancer will only make use of higher currents when there is higher voltage differences between cells. When providing a higher voltage/ charge from an external source you are providing that difference hence the higher rate of current being used by the balancer.
Great videos Andy.
How much power does your Tesla usually consume from your off
Grid garage per kilometre?
How does a charge current....that is equally distributed among the cells....creating a voltage difference amongst the cell?
Love your videos! With as many cells as you will have in the near future, the huge advantage of batrium is monitoring them all with only one "BMS". As for the cost...hey you can't take to with you...might as well spend it all!!!
Batrium got in contact with me already and we're talking...😉
I would like to see you leave it for a few cycles with the recomended settings from Victron. These guys know what they are doing - I promise you. :) leave it to absorb a couple of hours so the balancer can work at every charge. You changing back from the recomended settings make it so that we don’t have a proven state of the system actually working in this design. Then you can try fiddling with setting step by step until it stops working reliably. We humans sure are different and work toward a solution in different ways. Fascinating.
Yeah, I can do that and see how it goes over time. I've got the suspicion, that the balancer actually causes the imbalance because its permanently connected. If I don't fully charge for days or even weeks, it still balances and causes and uneven voltage once the battery gets close to full again. It then needs to revers that balancing again what it did in the past. It should only turn on if necessary or 3.5V or above maybe.
@@OffGridGarageAustralia I have wondered the same on these active balancers. I top balance my cells perfect and the bms so far on a couple battery banks has kept them within 0.010v but then if i don't get much solar for a few days or weeks and my bank is around 50% soc then an active balancer may be then be bottom balancing to a point so then when i get to a high soc again or when fully charged the cells are then out of balance.
@@OffGridGarageAustralia I have one of those balancers (4s) that I use with my Headway batteries. Something that I noticed is that when charging the pack and monitoring the cell voltages, the balancer will "artificially" increase the cell voltages that are low (and vice-versa) when it is actively balancing. This makes it hard to accurately monitor voltages unless you turn off the balancer. In my case it's easy for me to unplug the single 4s cable. However, you may want to solder a switch and some wires onto the balancer. (inplace of the solder blob that is there.) It would be Very interesting to see what the ACTUAL voltages of your batteries are when charging.
Andy have the balancer only turn on when you are approaching 96-98% SOC
For this cap transfer balancer there are two things that happen with lower cell voltage. First is the amount of transfer charge put in caps is less because voltage is lower to charge the caps. Second is the switching MOSFET's resistance goes up a bit because their gate drive voltage is lower. Both lower the net current transfer at lower cell voltages. Some models have a small boost DC-DC converter that provide a consistant gate voltage drive.
The balancer's cell voltage comparison is also more likely to be corrupted by external charging or inverter current in the flatter voltage portion of battery state of charge so it misfires occasionally pumping charge transfer in wrong direction.
I run lto cells and that balancer. LTO cells voltage will change more that other types. Charging at high currents the balancer can't keep up. I am talking charging at 1-5s. The problem with using this balancer is as you go lower the balance current is well under 1 amp. This makes cells go over voltage.
The mosfet version of the QUCC BMS works well. On cell high voltage it simply disconnects the charge circuit, the output remains on.
Setting the "balance on charge" to off allows it to balance while the charge circuit is disconnected.
I appreciate the maximum current on the BMS is only 120A, but this should not be a problem as it still gives you 5000VA.
When the second battery is installed you will have double that to play with, how much do you need ?
I have been reading good things about Seplos, they have a 48v 100a BMS that has the ability to connect with Victron
If the title is a question, it’s because during the flat part of a voltage curve the volts of the cells can be really close but the capacity of each cell can vary a lot at the flat part. That’s why balancing should be done at the steeper part of the voltage curve. The capacity of each cell is much closer at the steeper part of the voltage curve.
The same thing happens with my batteries. Most will be at 3,350v but as charging continues one cell continues to charge and comes over 3,600v and the others even drop from 3,350 to 3,330v
This starts to happen when the same saturation voltage stands for a long time. Does this rapidly growing cell have the least capacity?This is frustrating. 🙈
Well, because of your great testing and the gleaned information, I started looking into how the Active Equalizing Balancer works. So, far it appears to use 70 G045N03 directional current switching MOSFET with a current dispensation of 52 watts each in groups of four with the use of three capacitors. Regulated by what I think is some kind of voltage 555 type chip. I haven't got much further then that and its only a guess at this point.. So, this is what would make sense that that chip is set ate voltage you have described. If I get real worked up about it I'll test it. But, from what I think I know, I may just apply what you have done in this test once a month or so for a couple of days and the reset back to a lower voltage bulk charge. Anyways this information sure made it more fun to think about it all.
Thank you. That is great feedback. I'll look into it more as well. I have ordered some inductive balancers to compare...
Xr680f I think the last bit of your response, regarding balancing and resetting charge levels as maintenance procedure is the way to go!
Hi, Andy. currently enjoying your videos and will prowse plus various other van life videoes. Anyway I had a setup for camping with a 100Watt solar panel and dubious 240 v modified sine inverter wouldnt run AAA & AA charger..Have USB available and have found a EBL Charger upto 8 AAA & AA or 4C or D batts. Have tried tonight on AA & AAA batteries and seeems to do a goood job might even balance once one is fully charged however disconnected as was charging from a small solar power pack and fetching batteries out when fulll. Solar addictive! if I go above current setup need to consider earth when camping or keep at12volts? like what your doing for the community Might even do my first you tube vid on it over the weekend, but I have charged the batterries now. thinking about it never stopped you! time for a spat cheers
Consider testing against some of the inductive balancers. I suspect the flying capacitor units are able to get better balance, but they might be able to deliver higher current as the voltage difference gets smaller... though they do stop balancing pretty early (or at least mine does, but it's close enough for a 3s Lithium ion).
On the active balancer ,usually the thing does not kick in until there is a 100 millivolt difference between one cell and another. If a battery is under a charge as you do it of 20 amps how will you notice if it does anything? You won't so what you are saying is wrong again. It works all the time but you will not notice until you stop charging. Your cells have been to 3.65v before I presume so you must not go there again or you damage the SEI layer in the cell. Stay at 3.5 volts or less . You yourself said it makes very little difference in the state of charge . A few percent and you abuse your battery to get there.
Andy, do you think hooking up two or three of the HANKZOR Active Equalizer Balancer would work with the QUCC without the runaway situation? Since you now have two of them can you see if the pack would work better. I don't want to get a Daly, and I don't want to spend $600 on a balancer, so I am trying to figure out the best value set up, as I am sure most of your Subscribers do. I want to keep my cells in the 3.23-3.32 volt range.
You still need a BMS at a minimum, period.
ever thought about talking to someone with raspberry pi super smarts about setting up a unit that will monitor , heavy discharge/charge single cells thru relays or ssr and load or charger as needed?
Hey Andy you made it to 13K subscribers congratulations mate. I need to get back to building these DIY BMS. The DIY one does use can bus mate too.
Andy, how about using 2 ballancers in parallel?
One way to optimize battery would be first to accurately bottom balance. Then charge , the cell which goes high first is under capacity, increase the capacity of this cell by adding to it ,in parallel another small cell ...It's about getting the capacity of each cell block very close. Battery is limited by the capacity of the lowest cell.
Try turning the BMS balancing function off or set the start balance voltage higher than your absorption voltage so it can’t turn on. Let the active balancer handle that job alone. Balancers stop balancing, look at voltage and continue as needed. Two balancers on at the same time may be interfering with each other. Of course keep all other safety functions active on the BMS.
Hi Andy. At first, thank you so much for your videos. I’m always waiting to the next one. Here is my question : what if you double the balancer ? I mean, you parallel it with your spare one !? At best you lower the risk of battery disconnect… what do you think about it ?
Thank you for your commend and kind words, Sebastien. That is correct, I could increase the balance power by paralleling them together. That would effectively roughly double the balance current.
I have made the observation now that it is not necessary as the battery will balance over time. I haven't had fully charged the battery for a few weeks so there was quite a drift and the balancer could not keep up. Now, after several full discharges, the balancer has it under control again. I now charge to 3.45V only and rest there for 2h to give the balancer enough time to do its job. That seems to work.
Is 3.50v not the optimal maximum charge voltage per cell if you like to have the most of lifespan of the battery?
Hello Andy, please check the resistance between the busbar and the cable shoe from the BMS and the balancere. I had 20 ohm on it at one cell, ( I use the same 280 Ah cells ), and this is a big problem wenn the BMS gets no correct value. I changed the sequence , that the cable shoe is directly on the busbar. I thing in my case the V2a washer was the problem.
My english is not that good ,sorry .
With best regards Guido
Thanks for the tip!
Hi everyone... i was wondering how about connecting 2 bms's in parallel and set one to disconnect the charge and one to disconnect the load.... or is bad idea...?
Muito top
At around 2.44v cell 6 of my 8s 300ah battery shoots up in voltage. The Batrium does not discharge fast enough, so I added a 3s 5a balancer to the high cell and the 2 lowest cells, this helps but is still not enough! I am now adding another resistive balancer to it and have ordered more 5a balancers!
let us know. I was thinking the same thing. I hate when one cell just ruins it for the rest of us.
@@immrnoidall Try it. I seems to work. Have not had a rn away for 2 days
A good question to ask yourself is can you just stack the active balancers? it would be easy enough to make a pcb with some connectors or just use bus bars to parallel the balancers for a higher balance current. this would make the balancer more aggressive for these larger size cells. I feel that these balancers were only designed for 100ah cells and lower charge currents that would go with them
I think that too. The balancing current is way to small for this huge cells. And yes, you can parallel these balancers to provide more balancing current. Also you can load the cells to a higher voltage to get more in the upper part of the voltage curve to get more difference in voltage and therefore more balancing current out of these balancers. Also you can reduce the charge current so that the % of charge current to balancing current is better.
Absolutely great video. Thank you!
I am planning to build a battery with such a Balancer but 100Ah Cells and only 24V. I don't have such high charge current as you have, but I am really thinking it's perhaps a good idea to buy a second balancer for my pack to get enough balancing current 🤔
Great idea to communicate with charge controllers to lower current. But you don't need to do that. Just add a resistor in between batteries and charge controller. So use a separate port BMS and put a 30 ohm resistor across the charger/battery port so when the relay is off the charge controller will hit max voltage with just 1 amp or less.
Another point is that when that relay opens and closes it has a huge inrush to the inverter capacitors. Adding a resistor across it will help it stay precharged. But you need the inverter to be separate from the charge controller for this to work - in orther words separate port bms relays.
What about the resistor when the battery is at low voltage disconnect?
@@uhjyuff2095 Adding a resistor on the discharge doesn't do much for balancing since the BMS doesn't have a way to balance from the bottom. It can only shunt 0.1 to 1A at the top voltage. But having a resistor there can precharge the inverter capacitors.
Is there a manufacturing quality difference between the Heltec and the Hankzor generic? I need these in my particular setup.
They are 100% the same the same hardware and function, just the Heltec balancer has the printing on the PCB....
Thanks Andy. I love the channel by the way. You’re entertaining and I wish you were a neighbour lol from Michael @ West Coast NZ
I checked on the HANKZOR Active Equalizer Balancer and it states: "Equilibrium current 0-5.5A, the more balanced the battery, the smaller the current", and that is why you are not getting many amps out of the balancer when voltages are close, not by voltage of battery bank.
8:54 THIS is what i have been telling some folks... BMS without a communication to Inverter/Charger will disconnect the batteries from the Charger/Inverter when one of the triggers is reached (too high voltage, too low voltage, too high current charge/discharge, too high single cell voltage, too low single cell voltage). But they keep saying it does not because their inverter/charger is still running.
FACE PALM!
I said, BMS does not turn off the inverter; it disconnects the battery to the inverter and their inverter is now in battery-less mode.
what if we set chargers hi/low voltage,higher/ lower than bms cutoff voltages. I want to never need to "manually" do anything to cells of the battery bank.
would you be willing to conduct similar testing using a different active balancer? instead of using the one with capacitors can you show us how the one with inductors performs?
I can't remember if this was if this video or another one of off-grid garages active balancer test videos.. but at one point he has a board with four bulbs in it that he uses to drain individual cells.
Can anyone give pointers on how to do this? A regular house bulb doesn't have terminals... I've heard a car headlight might work but it looks like he's using something else. Just curious of all options
Edit: ah! It was this video. They look like car headlights....?
Does anybody know the details of building something like this? Do you need to worry about polarity on the bulbs? In series on the board? Polarity on bulbs needs to match the battery cell?
Any ideas on how to active balance 4 12 v lifepro4 batteries in series
What is that app. that you use on your phone to monitor the whole system?
Is that from the bms?
There is an app for the BMS and I also use Victron VRM.
Did you use 2 balancer, the from the BMS and the 2nd?
The BMS balancer was turned off at first but I set it to kick in at a higher voltage. So if the active balancer struggles, the BMS balancer activates as well and assists to bleed off energy.
@@OffGridGarageAustralia thank you for the information.
To balance fault due to variation in each cell at different voltage levels.Suggest to correct use smaller cells or.parallel cells 2 or 3 * S 16 which would average the variation same as Tesla battery.
That capacitor type balancer is excellence performance, am using that also in my 24v system 😊
i have been using BMS, 5amp active balancer and super capacitor to normalize sudden surge of current when using inductive loads, my lifepo4 setup is 4 years now, and still good and running.
Sounds good & simple, I do a similar thing to this usually. I’m Playing with some all in one systems atm, 24v 2.4kw & 48v 5Kw & have a heap of large Maxwell Caps, 48v & 16v strings I am using. Q) what size caps you using? What size battery bank? Inverter? Any solar? I am curious about any experiments or positive things you have noticed with the extra caps in the system. I have been thinking that I could get creative and hook a seperate balancer up to the caps to keep them at a bit higher charge right at the inverter input, higher than the battery supply voltage but below over volt protection of inverter with t-class protection, and keep extra bursting power available right at the inverter. With an all in one I can up the output voltage to a 64v Capacitor bank & probly dont need a balancer anyhow. I hope I haven’t bored ya!
Does anyone have anything they would like to add/mention about this idea ? Good or bad?
Thanks Andy
Wow I think adding an other chemistry like lithium ion using 14 cell @3.7 both of 16 cell lifepo4 have the same top and btm voltage limits but it will act as a buffer of fast voltage rise after 3.45 for the lifepo4 which would let the balancer do it’s job.
This is my hybrid battery and no balancing
230 amp lithium ion (Chevy volt battery) and 200 amp lifepo4 with top charge up to 57.4 volts absolutely no problems. Ant 300 amp BMS with no BMS on the 3.7 cell battery max difference is .05 after 5 years
Ok maybe a daft question. When do we actually turn off the active balancer.
Because is also balances in the flat area of the curve with LiFePO4 which causes an imbalance across the cells. Once you fully charge again, the balancer may not be able to balance that out again. You would then think it does not work or your battery has an issue.
I have made several tests with different batteries here on the channel showing that.
@@OffGridGarageAustralia Thank you
my Heltec balancer balancer works fine at any state of charge but it needs a little time to work it’s magic. Maybe Andy is impatient?
seplos bms can do the same...
Can you test these? Amazon no reviews and im having a issue with their capacity! Grade A 3.2V 310Ah LiFePO4 Battery Cells, Rechargeable Lithium Iron Phosphate Battery with Bus Bars and Srews, Automative Replacement LiFePO4 Deep Cycle Battery for Camper, Boat, Solar System...
Brand: AVinol
Can't get them here in AU.
I would be careful with no-name batteries, even if they are been sold on Amazon.
We have some reliable sellers on my website:
off-grid-garage.com/batteries/
That way Daly is batter than Yours BMS there are different keys for changing and discharging.
10:30 Seplos is the most used BMS in most chinese battery packs. They communicate with most inverters out there... and if you have an incompatible inverter/charger, tell them and after a day, they will send you the firmware.
It is far from the most commonly used BMS. The Pace BMS is widely used in server rack batteries, the JBD is widely used by the DIY community, Daly used to be popular, JK is popular with those that want a little more to play with. The Seplos BMS isn't bad but its quite expensive.
@@ericklein5097 You are correct that Pace is the most used BMS on battery packs. I mistook the similarity and made wrong conclusion.
Been researching diybms it's a control board and a per cell monitor board, once a single cell reaches a pre defined setting the current is cut off to the cell
Question: what happens with the excess energy you produce?
Thanks, I need time of catching up. I won't have you relay hard disconnect.
and all of the sudden everything in the house shuts off. litium is so fun.
You should be in absorb by 55.7v. The controller will back off and the bms will help
your cells have a different capacity, you need to capacity test each of them. and sort out the bad ones
No, that's not what you do...
More balancers would make the voltage delta smaller and that is what we need.
Will Prowse says in his videos that BMS's and balances are unnecessary once you have the batteries balanced from the start. Looks like he was wrong, huh?
If the internal resistance and capacity of your batteries is "Well Matched", you can go quite a while between balancings. If there are substantial variances in the batteries, balancers and BMS's can help reduce manual maintenance of them.
In b4 lead-acid users come in and tell you that you're doing it wrong lol
yep set charger disconnect volts, let the balancer drains them till it reach ur set reconnect ,when doing that the balancer works alone .oh dump unused power to ur grid tie inverter with a relay.
If you don't charge them every time to 3.55v, the pack will not stay balanced over time.
I'm having mine so I can do everything from my living room or tablet
A balancer will not work properly if you set the battery voltage to less than 3.6 volts per cell.
No it does work if you are charging with 3.5 amps you are only charging 1 cell with .200 amps. but discharging with .4 amps so it does help. Anywhere from 3.4 to 3.1 the cells will be the same voltage therefore the balancer on auto balance will not work. Balancers do not work on capacity they work on voltage. With such low production you could only drive to the end of the driveway most solar setups are concentrated on Kwh production.
It seems you may need the higher current balancer as the only time the balance has a chance to raise or lower the voltage on such high capacity batteries is in the steep parts of the curve, i.e. at the lower end or higher end. In the middle, the curve is so flat the balancer can't charge/discharge enough to have much effect on the cell voltage to achieve balance. So, higher current on the top of curve may win the race to beat balance before the BMS for shuts down due to one high cell being out of range