LiFePO4 BMS Wiring Help

[WalterM6]

So jealous! Congratulations!!!

Thanks

[flyons78]

Originally Posted by WalterM6

Good news. I got my batteries installed today. The problem with the runaway battery was solved by top balancing the cells. They are all now within 10mv. Set my max voltage to 53.6V, 3.35 v/c. That is supposed to be 99% charge. The idea about the binding posts worked out good. I got all the big terminals connections secure with them. Btw I went with 4 ga for the B8-B9 connection, it was more flexible. I took it out to test drive and the performance was similar to the leaf pack. I took it up the biggest and longest hills and the neither the battery or the terminals showed any great heat increase. That was one of the things I was worried about because of the small bus bars and hardware. The only thing I have left is to calibrate the SOC reading. I am now a happy driver.

Wow, awesome news! Interesting that your max voltage is at 53.6V. Did having that higher contribute to your battery problem? The battery specs list a charge limit of 3.65V per cell, but based on what you're saying it sounds like I may need to trim down to 53.6V as well.

How did you go about top balancing the cells? (In case I need to do this down the road)

Lastly, what is "calibrating the SOC reading"?

[WalterM6]

According to what I've read 53.6 is 99%, Anything above doesn't increase the charge much. And yes I think it may have caused my voltage/balance problem. My SOC problem is that my indicator is only showing 50% SOC at 99% I need to get it to read correctly. Attached is a video in case you need to top balance your cells. It my take a long time depending on your SOC. I hope your install is going well.

https://www.youtube.com/watch?v=x5ABvbbics8

[Sergio]

Where are you finding this information that 3.35 vpc is supposed to be 99%?

It is more like 3.53vpc for 99%.

[flyons78]

Originally Posted by WalterM6

According to what I've read 53.6 is 99%, Anything above doesn't increase the charge much. And yes I think it may have caused my voltage/balance problem. My SOC problem is that my indicator is only showing 50% SOC at 99% I need to get it to read correctly. Attached is a video in case you need to top balance your cells. It my take a long time depending on your SOC. I hope your install is going well.

https://www.youtube.com/watch?v=x5ABvbbics8

Dangit, you just sent me down a rabbit hole of knowledge with that video. This guy explains so much that I didn't understand. Now I'm getting all kinds of crazy solar power bank ideas with this information. Thank you, I think?

[dougs_huntingcart]

Originally Posted by flyons78

Dangit, you just sent me down a rabbit hole of knowledge with that video. This guy explains so much that I didn't understand. Now I'm getting all kinds of crazy solar power bank ideas with this information. Thank you, I think?

Yeah major rabbit hole.... just watched this one... I mean this is some great information and really assist in understanding this lithium set up and application of this bank in a cart.
https://www.youtube.com/watch?v=Yf9N9zBgyB8