I am just about to put together my first lifepo4 battery ever for a van build. I bought these cells and a daly 200a bms back in dec 2019, but the project got delayed and the cells have just been stored in the boxes. It is the same higee cells as keith among others have mentioned here in previous posts. I am a newbie on this, but I have generel technical understanding (even a masters degree in vehicle engineering, but it doesnt really help me here).
I've watched a bunch of youtube videos and read some posts here and came to the conclution that i should test ans top balance my cells. I just assumed that the BMS would take care of the balancing after charging but i realise bow it might not be that simple.
This is what I've done so far:
Measured each cell when they arrived and after 9 months stored. All 3.290-3.292 as marked, same now as 9 months ago. Built a box, connected the BMS and charged with 20A 14.6V charger. My idea was to try a couple of cycles hoping the cells would stay the same. This did not happen though. I ended up with one cell at 3.65 where the BMS shut off charging, and three cells at 3.33. I waited for a couple of hours and nothing changed and then i staryed doung some research and ended up here.
So what to do now? I have a battgo bg-8s balancer, a shunt battery monitor, a 20A 14.6V AC charger and a 2500w pure sine inverter to play around with. Ive seen some recommendations of charging and discharging individual cells to see how closely they are capacity wise, but i do not have a suitable charger.
My idea is to top balance with the balancer, fully discharge and measure capacity and individual cell voltage, charge again and see how they follow and if needed repeat. How doess that sound? Any other suggestions?
The cells are slightly bulged when I check closely (1-3mm) but they look new, have serial numbers and BLS claims they are new grade A.
I would really appreciate any support on how to proceed. I would ideally spend as little time and work as possible and get the pack ready.
Btw, does anyone now the balancing algorithm in the Daly 200A BMS from 2019? I read somewhere that it just puts a 1A load on tye cell that are above the other. There is no measurable current in any of the BMS balance leads now when one cell is 3.65 and the other 3.33. I will now leave it overnight and see if anything changes.
I've watched a bunch of youtube videos and read some posts here and came to the conclution that i should test ans top balance my cells. I just assumed that the BMS would take care of the balancing after charging but i realise bow it might not be that simple.
This is what I've done so far:
Measured each cell when they arrived and after 9 months stored. All 3.290-3.292 as marked, same now as 9 months ago. Built a box, connected the BMS and charged with 20A 14.6V charger. My idea was to try a couple of cycles hoping the cells would stay the same. This did not happen though. I ended up with one cell at 3.65 where the BMS shut off charging, and three cells at 3.33. I waited for a couple of hours and nothing changed and then i staryed doung some research and ended up here.
So what to do now? I have a battgo bg-8s balancer, a shunt battery monitor, a 20A 14.6V AC charger and a 2500w pure sine inverter to play around with. Ive seen some recommendations of charging and discharging individual cells to see how closely they are capacity wise, but i do not have a suitable charger.
My idea is to top balance with the balancer, fully discharge and measure capacity and individual cell voltage, charge again and see how they follow and if needed repeat. How doess that sound? Any other suggestions?
The cells are slightly bulged when I check closely (1-3mm) but they look new, have serial numbers and BLS claims they are new grade A.
I would really appreciate any support on how to proceed. I would ideally spend as little time and work as possible and get the pack ready.
Btw, does anyone now the balancing algorithm in the Daly 200A BMS from 2019? I read somewhere that it just puts a 1A load on tye cell that are above the other. There is no measurable current in any of the BMS balance leads now when one cell is 3.65 and the other 3.33. I will now leave it overnight and see if anything changes.