DiploStrat
New Member
- Joined
- Sep 8, 2020
- Messages
- 12
Built three 280Ah batteries with EVE cells and Overkill Solar BMS. to mount in my overland camper. Charging is from solar, alternator, and Magnum inverter/charger.
Two batteries have been textbook perfect in about two months of use. This includes induction cooktop, a ton of fans, and overnight air conditioner runs. Cells remain balanced within 0.00x volts, except at the very top.
The third battery has one cell, number four on the BMS readout, that is almost always low. Here the delta between cells is typically about 0.05 volts. Battery voltage tracks the other two, but the BMS generally rates it at about 2-3% lower SOC.
Under load it appears to drop a bit slower. One night, when it was turned off, it appeared to drop its voltage much faster than the others.
All 14 (was advised to order extras) cells were originally top balanced in parallel.
I have double checked the BMS leads several times, and cleaned and reconnected the BMS leads.
Soooo, I propose the following:
-- Remove the offending batteries and top balance along with the two spare cells.
-- Reassemble with the orignal cells, changing the order.
If all is well, have a Merlot. If not,
-- Remove again and remove offending cell. Reassemble the battery with one of the spares.
-- Top Balance again and reinstall.
Questions:
-- Any comments?
-- With Overkill Solar BMS, which is cell 4? Closest to + or closest to - ?
Many thanks!
Two batteries have been textbook perfect in about two months of use. This includes induction cooktop, a ton of fans, and overnight air conditioner runs. Cells remain balanced within 0.00x volts, except at the very top.
The third battery has one cell, number four on the BMS readout, that is almost always low. Here the delta between cells is typically about 0.05 volts. Battery voltage tracks the other two, but the BMS generally rates it at about 2-3% lower SOC.
Under load it appears to drop a bit slower. One night, when it was turned off, it appeared to drop its voltage much faster than the others.
All 14 (was advised to order extras) cells were originally top balanced in parallel.
I have double checked the BMS leads several times, and cleaned and reconnected the BMS leads.
Soooo, I propose the following:
-- Remove the offending batteries and top balance along with the two spare cells.
-- Reassemble with the orignal cells, changing the order.
If all is well, have a Merlot. If not,
-- Remove again and remove offending cell. Reassemble the battery with one of the spares.
-- Top Balance again and reinstall.
Questions:
-- Any comments?
-- With Overkill Solar BMS, which is cell 4? Closest to + or closest to - ?
Many thanks!