Length of time to charge 280ah battery280

[ddutton]

I have 8 280ah batteries for a 24 volt system. Have batteries connected in parallel to a 10 amp bench power supply to top balance. Have been charging for a week, only in evenings when I'm not working, I don't let them charge unsupervised. They are now at 3.32 V. How long should this take. I started with the alligator clips. big mistake, and am now using 10 gauge cable a ring clamps. How long should this take in hours?

 

[ereams65]

I don't know the math, but sure someone will weight in with that formula. I do know, they will take what seems like forever until they close to full and then move up rapidly. The 10ga will help a lot. If you have a BMS, some people even recommend charging them in Series with the BMS monitoring until you get closer to the top, then tear the pack down and put them back in parallel to finish.

 

[upnorthandpersonal]

Assuming they are at 50% state of charge, that means you have 8x140Ah, or 1120Ah to go. At 10A, that means 112 hours, or about 5 days. Patience is key!

 

[ddutton]

Yikes. I think I will connect up as bank with BMS the I can let them charge 24/7. Then strip and connect parallel at the end to finish the top balance. Thanks guys.

 

[ereams65]

I would still monitor the BMS. Anything man-made can break.