SOC when adding 48v server rack batteries

[Hymie]

When connecting 48v server rack batteries in parallel do they need to be at the same state of charge?

 

[acdoctor]

They do. If the voltage is different a large current will move from the higher SOC this can cause problems. Also if you ever expect them to have the same SOC they need to start out the same.

 

[BentleyJ]

When connecting 48v server rack batteries in parallel do they need to be at the same state of charge?

When connecting batteries in parallel it is important that the resting voltage of both is within about 0.2V otherwise it is quite possible to get a very large current exchange from the high battery to the low battery.

 

[Ampster]

Also if you ever expect them to have the same SOC they need to start out the same.

The voltage will equalize eventually regardless of how they started out in parallel, SOC is really a derived number.

 

[Ellcon123]

Off Grid Garage has tested this and possibly Will. Packs will equalise voltage and balance themselves out at full charge. Certainly been my experience.