JK BMS conundrum. I am defeated, need help

[Hynek]

I'll try and keep this short and sweet so please bare with me.

I finally ditch the lead/acid and upgrade to a 48v16s lifepo4 system with JK B2A24S20P, batteries are EVE 280K. Everything works great, cannot be happier
The neighbors looking to upgrade as well, buy exact same batteries and bms. This one is connected as a 24v16s system, figured on using same bms because they can add another 8 cells in parallel later if they need some more capacity.

I connect BMS and this unit is only seeing 8 of the 16 cells, 1-8 no 9-16. Will not allow charge or discharge to turn on. Thinking maybe bms is defective, I swap it out with mine and it works just fine, sees all 16 cells right away. I try to rearrange the order of leads with not avail. No idea on what to try next

I'm thinking its possible that the JK B2A24S20P does not work with a battery in parallel. But can't figure any reason why it wouldn't. If anyone has any info or things to try please let me know. I'm at a dead end

Thanks in advance

 

[sunshine_eggo]

24V requires an 8S BMS.

It doesn't work with a battery in parallel. The cells must be paralleled first forming 8 560Ah cells in a 2P8S config.

Parallel batteries require a BMS for each battery.

I don't know if your specific BMS works with 8S.

 

[Hynek]

I was afraid I was going to hear that. That bms did work when I lowered the cell count to 8 in the app. dang

 

[Skypower]

You can run it 2-P 8-S.
2 in parallel 8 in series.

 

[Skypower]

This is an example of a 2 in parallel 16 in series that I changed to 2 banks. If you want to use 16 cells to make 24 volts yours would look like half of the picture (to the black cross beam.

 

[Hynek]

You can run it 2-P 8-S.
2 in parallel 8 in series.

Your pic is interesting. I had this connected like a 2p8s but not like that

I drew yours on a piece of paper and looks just bonkers to me. I had the other 24v system connected with just two packs of 8 batteries in series connected together.

 

[Skypower]

It doesn’t matter what shape you make it as long as you have it electrically like this;

 

[Skypower]

I went away from the 2P layout because the Daly bms failed. I went with 2 batteries 16s for redundancy and recently added number three. I now have three of the exact same BMS’s that you have. I could also eliminate the extra balance leads of the Heltec active balancer.