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Experiences or opinions on the Chargery BMS?

I don't see that cells not matched, if I compare cell #4 for example, we are getting 1.9 / 0.3
 
Thanks all for your help. But I have feeling that almost every piece of info I'm posting, everyone trying to defeat this by telling me that everything is wrong with battery/wires/hands etc. But not chargery BMS.


Thanks again, at this point I'll continue research by myself.
 
I don't see that cells not matched, if I compare cell #4 for example, we are getting 1.9 / 0.3
I most definitely could be wrong but i would expect all those numbers of IR to be the same or much closer if cells were matched.

And again i'm not that confident of the Chargery IR measuring but it is better than nothing to help you get to the bottom of the situation.

the Chargery definitely could be doing something wrong but your reports do not prove anything yet this is my problem with your post. If you could get an amp reading from the BMS leads it would tell you for sure if the Chargery was using power on some cells and not others.

Lastly I want to know if Chargery has issues I just need to know its the Chargery not something else. I have three in use with 0 problems. I have had some though that were calibrated poorly and gave bad readings on cell voltages.
 
I don't see that cells not matched, if I compare cell #4 for example, we are getting 1.9 / 0.3
You say the cells are Grade-A, they likely are BUT they are NOT Matched & Batched from a Test Facility. They are COMMODITY CELLS which means they made qualification for being Grade-A at Production and passed the "Basic Tests" for compliance. The Vendor / Reseller did not put them through a Matching & Batching process as that can add up to $50 per cell for larger capacity cells. This applies to ALL Lower Priced Cells.

Because you are dealing with UNMATCHED cells (which means they will have varying IR at different voltage levels) you will always have fluctuation regardless. This fluctuation / Differential is most noticeable at the top voltages of the cells above 3.55V most typically.

Ohh, just noticed, 3 cells in Parallel, 16S pack with one 16S BMS.
NOT Matched cells, just commodity specials.
IR evaluations on Paralleled Cells = 100% USELESS !
Can't determine the IR of a cell when 3 are in parallel - they are ghosting each other. FACEPALM MOMENT THERE !!!
In fact, split the parallel cells up and test EACH CELL for Voltage - better sit your butt down before you do that, you will likely be in for a nasty surprise...

Put 3 Adults on a weight scale, 1 weighs 50kg, one 60kg, and last one 65 kg. for a total of 175kg. But you cannot physically see or identify them in any way, male, female, tall, short or skinny/fat.... You ONLY know it's 175kg and the average is 58.3kg.

READ THE COMMENTS ON YOUTUBE, the Answers are there.
I do not think blaming the BMS for unmatched paralleled cells misbehaving is wise.
No wonder the poor BMS is having stressful days.
 
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ANYONE Using a Chargery BMS 8T 16T or 24T with Lithium Ion Chemistries besides LiFePO4 ?
Tesla, Volt Packs ?
Other New / 2nd Life ?
IF YES : Have you noticed any of the issues presented ? If So, what chemistry / cell type are you using ?

Please tell us your BMS Model, Battery Chemistry being used, is passive balancing ON or OFF, and do you have an external Balancer (Active or Passive) what make & model if you do please.

Thanks in Advance for your input.
 
Internal resistance:
View attachment 24947

one hour later:
View attachment 24946


Active balancer was off entire time.
please do the below test to locate the problem,
1. disconnect load and charger, turn off balance, measure each cell voltage with multi-meter and compare with BMS cell voltage reading. find which cell voltage reading is wrong (over 20mv difference with multi-meter),
2. discharge total battery pack at over 20A for over 5 seconds, then stop discharging, take a IR reading picture, find IR difference.
waiting for your testing result.
from video, the battery temperature reach 97 Fahrenheit degree, BMS display 27 Celsius degree, please put the temperaraure sensor on the highest place. confirm if the BMS display wrong battery temprature.

thanks.
 
please do the below test to locate the problem,
1. disconnect load and charger, turn off balance, measure each cell voltage with multi-meter and compare with BMS cell voltage reading. find which cell voltage reading is wrong (over 20mv difference with multi-meter),
2. discharge total battery pack at over 20A for over 5 seconds, then stop discharging, take a IR reading picture, find IR difference.
waiting for your testing result.
from video, the battery temperature reach 97 Fahrenheit degree, BMS display 27 Celsius degree, please put the temperaraure sensor on the highest place. confirm if the BMS display wrong battery temprature.

thanks.
1. Disconnected balancer/relays cable/charge/discharge, waited for 5 min, compared voltage reading from BMS with multimeter - max V diff 8mV.
2. Discharged battery for 1 min with ~40A.

IR before discharge:

IMG_3176.JPG



IR after:

IMG_3182.JPG



On video MAX cell temperature 82.2F (27.9C) and BMS reads about the same temp.

Thanks.
 
1. Disconnected balancer/relays cable/charge/discharge, waited for 5 min, compared voltage reading from BMS with multimeter - max V diff 8mV.
2. Discharged battery for 1 min with ~40A.

IR before discharge:

View attachment 25191



IR after:

View attachment 25192



On video MAX cell temperature 82.2F (27.9C) and BMS reads about the same temp.

Thanks.
thanks for your testing,
the cell voltage reading on BMS is OK, battery tempreature reading is correct too, the cell impedance difference is big (0.2 mohm min, 2.0mohm max.), the cell impedance with over 0.8mohm is bad, these cells don't matched.

do you think what the the problem on the BMS is ?
thanks
 
thanks for your testing,
the cell voltage reading on BMS is OK, battery tempreature reading is correct too, the cell impedance difference is big (0.2 mohm min, 2.0mohm max.), the cell impedance with over 0.8mohm is bad, these cells don't matched.

do you think what the the problem on the BMS is ?
thanks
I don't know what is the problem...7
My thoughts that BMS is culprit:
1. BMS temp is 20-30F more then other items in cabinet. Considering that BMS balancing is off, and temperature changes (sometimes temp diff could be just 5F, sometimes 30F), BMS doing something that I cannot understand.
2. Test that I did with pack with/without BMS (item #3 in video description) tells me that pack itself is not going out of balance.
3. I contacted Chargery and explained issue, they offered to send BMS back, that tells me that something could be repaired there.
4. Same issue with 1st BMS (only one cell was drained), at that time I disassembled BMS sent photos to Chargery, and they told what component failed.
 
About the Chargery BMS, it's stated in the data sheet that it features over temperature protection and differential temperature protection (between both temp probes I guess, but we don't know what this protection cuts: charge and/or discharge?). But what about low temperature protection, to forbid the charge next to freezing temperatures? It seems like an important need no? Tiny BMS has it, but I can't find it anywhere for the Chargery BMS.
Chargery folks added low temp cutoff about 6 months ago. It is not reflected in the documentation yet.
 
Protection functions 1. Cell count error protection 2. Over charge protection 3. Under voltage protection 4. Over current protection when charge or discharge 5. High temperature protection 6. Low temperature protection (on LCD unit V3.03) 7. Over differential cell voltage protection in discharge 8. Over differential battery temperature protection 9. Under SOC protection
pg.5

You have to be running with at least Version 4.0 firmware.

Doc to update.

You will want BMS16T main unit update to V4.0
BMS16T LCD module update to V4.01
And the latest manual.

Yes, the electro-mechanical relays get hot, energy saver TE/Kilovac types barely warm.
 
we just released new firmware for BMS8T, BMS16T and BMS24T. both main unit version and LCD version is V4.02

the update are as below,

On new version V4.02, new update:

  • Optimize current measurement, with 100A shunt, the BMS can detect 0.3A minimum, with 300A shunt, the BMS can detect 0.5A minimum. The AH and WH accuracy is improved at the same time.
  • Optimize cell voltage measurement, improve the cell voltage accuracy
  • Modify over current protection resume from automatically to by manual.
new manual is as below, more details please check the final page of manual.
New Firmware is here, https://chargery.com/update.asp
our testing result state clearly the current is very stable and accurate, if curent reading on BMS still have fluctuations, please email me to jasonwang3a@163.com, i will try my best to fix it, maybe need modify hardware.

new BMS8P, BMS16P, BMS24P will be with RS485, and CAN communication, the cooling fan will be added, new hardware and new program, continue to balance will be realized, for battery with large capacity difference, large impedance difference and large cell volage difference will be resumed at the shortest time, 1A balancing current will remove 10AH difference within 10 hours.

the cell IR measurement is still an importang tool, it can indicate cell actual difference, it is easy to tell you which cell is bad (lower capacity and higher impedance), and need to exchange.

about parameter setting, don't setup the protection point to the highest or the lowest as descriped in cell/battery datasheet, it is abosulutely maximum or minimum value, and don't reach it abolutely, that is to say, if over it or under it, the cell or battery is dangeous, so it is not suitable in actual using, unless you need test cell/battery actual capacity, because the capacity listed on cell / battery datasheet is tested according these maximum or minimum conditions.

good luck and thanks for support.
 
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