Battery

[bj1]

New here. Need some help.
Recently converted from lead acid to lithium batteries. I built two banks of 3.2 EVE LIFEPO4 batteries (48 volt system, so 16 battery each bank) with each battery having its own JDB bms 7-20s.
I hooked up the bms’s in parallel, I have read some say do not do that other say it works fine. But mine charges fine with the solar arrays, but at night only one battery is discharging. The bright blue led is on on the one that is working and not on on the one that is not working. If I take the bms out of the system and then hook it back up it work fine till the next night, then I have the same issue.
Would appreciate some advice. Thanks

 

[time2roll]

What happens if the BMS that shuts down is left in the circuit and the functioning BMS is removed?

Does the BMS remain shut down when the solar starts charging?

How far does the voltage diverge between the batteries with one BMS shut down?

 

[Steve_S]

Your Terminology is incorrect and will lead to issues further on.
A Battery is a collection of cells with a BMS.
A Bank is a collection of Batteries set in Parallel.

You have 16 Cells in Series with a BMS and THAT is a battery.
Your typical 12V Car Battery has 6 cells which makes it a 12V Lead Acid Battery.

REF: covering battery configs from Victron Systems. Pay Attention to pgs 16-19

https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

As for connecting JBD BMS' in Parallel that is perfectly fine.
Most "BMS Boards" do not do well if setup in SERIES some will not work at all and some will with Limits.

Hope it helps, Good Luck

 

[bj1]

I removed the good battery and the other battery immediately came on.

 

[time2roll]

Sounds like it might be going into a sleep mode. As long as it wakes up when there is a voltage differential or current flowing I would assume all is normal. Make sure it wakes up both during charge and discharge cycle.

 

[Blue Sky]

New here. Need some help.
Recently converted from lead acid to lithium batteries. I built two banks of 3.2 EVE LIFEPO4 batteries (48 volt system, so 16 battery each bank) with each battery having its own JDB bms 7-20s.
I hooked up the bms’s in parallel, I have read some say do not do that other say it works fine. But mine charges fine with the solar arrays, but at night only one battery is discharging. The bright blue led is on on the one that is working and not on on the one that is not working. If I take the bms out of the system and then hook it back up it work fine till the next night, then I have the same issue.
Would appreciate some advice. Thanks

16 cells each bank, and then connect to the BMS, so you need to build 2 battery bank, each bank is connected to the BMS, and finally connected in parallel, is this practical?

 

[Allendo.can]

You can test whether each bank is normal separately.

 

[bj1]

Each battery with its individual bms works fine separately. If I only charge the batteries to say 85% they both discharge collectively. But if I charge to 100% (according the the app for the bms) then only the one battery will discharge. It’s always the same one.

 

[time2roll]

And the app does not say the discharge is shut off? Or any type of fault mode, sleep mode? Just ready.
Does it remain off as the batteries get maybe 500mV out of balance?