Parallel battery banks

[Norm01]

I know there has been much discussion about this and the fact that Daly and JKS don’t support parallel unless in Daly’s case you buy a parallel module. I am building a second 12v battery bank. Both batteries will have CATL 302a cells and will both have a B1A8S20P-H-C. If you consider that Lithionics, Battle Born, Renogy and many others are connected in parallel routinely in an RV, why would it be an issue for me to do the same. I see people advocating fast blow fuses which I don’t understand as the BMS will protect the surge of current. Sure you need to level off both batteries first and set exact same parameters in both BMS but other than that I don’t understand any negative issues.

 

[sunshine_eggo]

I know there has been much discussion about this and the fact that Daly and JKS don’t support parallel unless in Daly’s case you buy a parallel module. I am building a second 12v battery bank. Both batteries will have CATL 302a cells and will both have a B1A8S20P-H-C. If you consider that Lithionics, Battle Born, Renogy and many others are connected in parallel routinely in an RV, why would it be an issue for me to do the same.

It's my understanding that most recommendations against parallel of specific BMS are to prohibit paralleling ON THE SAME BATTERY - some folks have done this. Confusion stems from poor communication across different languages.

I see people advocating fast blow fuses which I don’t understand as the BMS will protect the surge of current.

BMSs fail. The FETs that open/close the circuit tend to fail closed.

Sure you need to level off both batteries first and set exact same parameters in both BMS but other than that I don’t understand any negative issues.

Yep.