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Cheap Chinese Active Balancers
#11
(11-19-2019, 02:48 AM)jonyjoe505 Wrote: The middle one, I bought the 4s version(20 dolllars) and Also after 5 hours the battery was still out of balance but it did  balance a small bit. But it would be insignificant.It does work but very slowly, it would take days to balance an out of balance pack. But it will keep a pack that is mostly balance, in balance.


That's curious considering it's supposed to transfer charge at the rate of several amps - so I guess the rating is bad. Do you have any data you'd like to share with that unit? 

I just bought the same one *facepalm* so I'll be testing it as well. I've been working on a DIY BMS, and the most annoying part for me has been the balancing. What I liked about that unit is that it has an on/off switch (a trace on the PCB you can cut and hookup to a switch) to turn balancing on and off. 
I'd like to also measure the current and see what it is actually balancing at.

Based on your feedback it seems like it's a dud and I might be better off with what I was doing - a resistive balance board that is separate. Either way I'll test it and share my results. 


Other than that - a BMS system would just need to do low and high voltage cutoffs which is much easier to implement. There are a bunch of cheap $20 current meters on amazon that... well they aren't perfect but they are close enough for users like myself who are using sub 5kwh systems
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#12
there was a new version that came out that has red capacitors instead of the blue ones,. its suppose to be an improvement. The ones I have just don't balance fast enough. When I tested it, I used a severely out of balance pack, and its performance was not good. During the test I also used a 3in1 lipo tester (which has resistive balancers) the 3in1 tester(cost 10 dollars) easily outperformed the active balancer.

The chargery bms8 that I have on my 4s 220ah lifepo4 , has 1.2 amp resistive balancing, you can adjust at what voltage you want them to come on, you can also turn them off. Very good bms all around.


3in1 tester works better then the cheaper active balancers 
 
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#13
I bought the red resistor one myself. I checked youtube and looks like one person made a video which... I can't really decipher but I think it shows him getting almost 5amps of balancing current in his testing.
https://www.youtube.com/watch?v=-RfMKpyHkm4

Looks like his setup is 5 cheapo multimeters soldered on to measure current draw, and that exact 3in1 tester you have to measure voltage.

He's even tested this 1a version and it seems to be working...
https://www.youtube.com/watch?v=40rAkqBz8Vk

What I would use is the 5amp version - which would be automatically controlled via my bms. This way I can also keep track of how long equalizing was kept on for
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#14
Thanks for starting this topic. i have a similar story. I have 12x or so of those BAE bus packs and 480x new 32650 lifepo4 cells, totaling 1584 cells and 15kwh. each half of the battery has its own high quality top balancing BMS, but and a strange thing happens recently. Overnight it would turn off and error out my magnum inverter and transfer switch, leaving me in the dark. when i commissioned the system in august 2019 when it was sunny, it would top balance every day sitting at 54.4VDC for hours and i never had issues. now that we are into the late fall in the northern hemisphere, and i have double the pack capacity size over time from 7.5 to 15wkh, it almost never gets to 3.60V/cell which is the threshold for balancing in a typical LI-FE BMS. so in a matter of a 3 or so weeks one of the cell layers out of 15s was drifting down to 2.5V/cell when the others are at 3.05v/cell causing the BMS to activate the protection circuit and disconnect the power before my transfer switch got to its own 46.5 volt trigger level to go back to grid.

I think the solution is to have both an active and passive balancers on at the same time. the top balancer provides over and under volt protection for the pack and the cell levels (the stick.) And the active balancers provides more capacity and balance with shallow cycles between middle and low charge levels (the carrot.) i'll be in $140 for both active and passive ballance at the 100amp/150amp/hour scale. my red-cap'ed 17-16-15-14s active balancers will arrive 1/2020 and cannot wait to install them with the shortest possible but equal length, 16awg gauge wire, until then i'm manually bottom balancing the packs with a smart charger once a week. i have a youtube channel search for solar porch nissan leaf.
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#15
No
Active chinese cheap balancers Will hide your issue and just delay it slightly. The problem above is that you didnt check it in time and fix the issue. For instance swapping out the self dischargibg cells.

Another is to set balancing to start eatlier. You state you have a high quality bms then you can set that.

Dont hide the issue you have. Fix it instead. A proper passive bms would handle it even without not getting a full Charge.

Getting active balancer is just an excuse not wabting to remove cells that are faulty
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#16
(12-13-2019, 05:34 PM)daromer Wrote: No
Active chinese cheap balancers Will hide your issue and just delay it slightly. The problem above is that you didnt check it in time and fix the issue. For instance swapping out the self dischargibg cells.

Another is to set balancing to start eatlier. You state you have a high quality bms then you can set that.

Dont hide the issue you have. Fix it instead. A proper passive bms would handle it even without not getting a full Charge.

Getting active balancer is just an excuse not wabting to remove cells that are faulty

There are two Li-Fe packs each 7.5kwh, one with brand new cells and one with used BAE bus packs. both had the issue where the BMS would go into protection mode after a few weeks of not top balancing. my BMS is not programmable. to get the low cell layer back to the same volts as the other cell layer (2.5v up to 3.15v, a bottom balance) it put 1.5ah into the new cell pack and 750mah into the used cell pack with the smart charger, consider each is a 160ah cell layer, that is less than 1%. is that really a problem? based on that i figure a 5 amp active balancer is many thousands of time overkill to meet the need of  making up 1.5ah over a few weeks.
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#17
IF its less than that in drift its not a problem and i dont see why you would even consider getting expensive active system hiding it.

I have alot more drift over Winter than that and i dont get into issues Smile
IF that small amount is tripping under voltage you drain the pack to much from start.

Chasing that last 1.5ah isnt worth it
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#18
Hi ,Dave ,
The active bms wasn't a cheap balancing bms , so that 2 options you had posted 
Wasn't active ,that's balancing by resistance
Wendy
<Email removed>
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#19
So this 1A JK-B1A24S active balancer I have now comes with a new version that has CANbus. I was going to try and figure out how to communicate through the bluetooth interface but wish I'd waited and got this instead.

https://www.aliexpress.com/item/4000252216391.html

The seller has provided some documentation on it, and I had to do some google translation from chinese to english. Thought this might be useful to someone.


Attached Files
.pdf   JK-DZ08_B1A24S_V4.pdf (Size: 268.03 KB / Downloads: 14)
.pdf   JK-DZ08_B1A24S_V4.zh-CN.en.pdf (Size: 697.6 KB / Downloads: 18)
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#20
I've had the red cap active balancers 15s installed for 17 days and the cell layers are within .01v, so they definitely work. Also I do think they unlocked more capacity, 1/6/2020 was really sunny in Ohio and I charged up record 15.3KWH. This chart shows a day from fall ’19 without the active balancers and then then both 1200xBAE + 450xVaricore batteries with active balancers, so two things changed, but I’m happy with it.


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