Changing serial to parallel

[Sensaciones]

I found 4 second-hand AGM batteries (12V/250Ah/identical of same date in 7/2020). They were used for just 3 months in serial (48V system).
I plan to use them parallel (12V system). Any problem with that?

 

[Porch]

I can't see any issues. Go for it.

 

[Steve_S]

When connecting Lead like this, there is one very simple rule that applies, even if batteries themselves are identical, the weakest in the lot rules the roost ! Given the "Age" that should be no problem, BUT if they were abused, IE dropped below 50% DOD or pushed to limits they may have suffered some degradation... Lead / AGM is pretty tough over the short term, they can & do get a bit more finicky as they age up later... Really does depend on grade/quality & class of battery... IE Heavy Duty Deep-Cycle vs Motive Type or RV/Marine.

 

[Sensaciones]

Thanks for the detailed response. They are U-power UP-TFS250-12

 

[chladekj]

4x 12V/250Ah paralel connected, pay atention to use enough wire cross section depending on planned charge and discharge current and fuses.