Ahh…okay, thanks. He mentioned he thought they were the same cell so I assumed that he was saying Vapcell rewrapped it and any of his comments would be apply to both. Now that you mentioned it though, I have a memory of someone talking earlier about FEB cell quality.
Really cool, thanks.
What will be interesting is the release of the M65A, P60B, P60C, XA3, 22S, 30S, and 50S all within a fairly narrow time window. I’m guessing a couple of years before the P70, P85, and the other XA Series cells though.
Thanks
I have the FEB 6000mAh datasheet. If you need it, you can message me privately.
My understanding is both of those are only in B/C sampling stages
Today, I got similar answer when asking about them.
Sending a PM
I charged the cells to an average of 4.06 V. After the first test drive on the race track (25 km) with 750 A discharge and 240 A recuperation, I noticed that the cell voltage had dropped to 3.2 V. What I noticed while observing the cells was interesting: The voltage in the 1st to 6th parallel groups increased, the voltage in the 7th to 25th parallel groups remained the same, and the voltage in the 26th to 32nd groups decreased. The whole thing looks like a pyramid. Does anyone have an explanation for this?
This is probably due to temperature deltas and other interconnect bottlenecks.Reliance 50RS
Finally, the time had come and I was able to test the 16P32S Reliance 50RS battery packs
I can, however, praise the cells, as they never exceeded 40 degrees Celsius (air-cooled, of course) and were still able to deliver 750 A with 16P on the second test drive despite the cell voltage dropping to 2.8 V.
If anyone is interested, I can upload a short video of the race track during the second test drive.
The battery pack's busbars and busbars are identical between the groups. They are comparable to 40 mm² copper cables. The battery pack is connected to the control box via a 50 mm² cable. It could be that due to the different cable dimensions, the first and last parallel groups can produce more power than the others, or, as BlueSwordM suspects (the cells before the cooling structure are the coolest compared to the other cells), the first 1-6 and the last 32-26 groups are better ventilated. Thanks for your help.
I agree with your theory, as the coldest cells are from 1 to 6 and from 32 to 26. I'll reconfigure the temperature sensors during the next test to complete the process, so I can measure groups 1-32, 3-29, 6-26, 11-21, and 16-17 and determine the temperature difference. Thank you very much for your tips.
*Hypothesis.
At what voltage does your BMS start balancing the cells?
*Hypothese.
Eine Theorie ist etwas Bewiesenes, und wir haben noch nichts bewiesen
Ich frage mich, ob Sie die Temperaturdifferenzen verringern können, indem Sie vor dem Rennen auf etwa 30 °C vorheizen.
Das macht Hyundai mit dem Ioniq 5N auf langen Rennen.
Balancing starts at 3 V and draws only 170 mA. I'm considering installing a 4 A active balancer as well. At the beginning of the video, I had 110 V in the battery pack. During the last lap, the cell voltage briefly dropped below 2.8 V (1-6, 26-32 parallel groups), which triggered a low-voltage alarm. After the last lap, the battery indicator shows 101 V. Unfortunately, I didn't take any photos of the cell values after the last lap.
Unfortunately, I've just realized that I'm not allowed to upload a video file directly here. However, I have videos on my YouTube channel not of the new chassis and battery pack, but of the old chassis and with the old battery pack.
I would start balancing only in the upper SOC area. I balance only above 3,9V, but these are active balancers with 1A and 2A on my battery packs.
