Mixing SOK and Renogy 100Ah LiFePO4 batteries in parallel

[ooeybc]

I recently purchased 2 new SOK 100ah LiFePO4 batteries which I would like to combine in parallel with 2 Renogy 100Ah 12V smart Lifepo4 batteries. The Renogy batteries are 2 years old but are lightly used with less then 10 charge cycles and have been stored in shelf mode for most of the time. Both brands have integrated BMS, and the SOK batteries are self heating but not the Renogy batteries. Is this doable?

 

[50ShadesOfDirt]

I would ask each vendor about your intended parallel configuration of different brands, to see what they think about another vendor's bms working with their own bms, per your model of each brand.

If it had been the same brand, and the vendor states that the configuration is permitted, then obviously no problem. When mixing brands/vendors, asking each one, via their tech support line or email, might uncover a possible issue.

I would also use busbars in the most efficient cabling pattern, to give each bms a good shot at available charging power, vs a cabling pattern without busbars. A google search (or other threads on this forum) will give you the background on busbars and battery-bank layout for parallel configurations.

Hope this helps ...

 

[mikefitz]

There should be no issues using different batteries of the same capacity in parallel. Idealy charge each battery to a full state of charge separately. This may result is some of the batteries displaying BMS charge path shutdown when near full, with the charge voltages you are using. Set the charge voltage suitable for all the batteries, ( this could be as low as 13.8 volts) that is just below the voltage where BMS shut down occurs.
Connect all the charged batteries in parallel. Refere to this for ideal battery interconnection,

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You may see unequal charge current at low temperature with the self heating batteries accepting charge whilst the Renogy are not. Exacting how this will affect your use of the battery pack is uncertain. Perhaps evaluate performance under low temperature conditions and modify the pack if required.
Note both the SOK selfheating batteries and the Renogy smart batteries have unusual , but different, BMS shutdown events under some conditions.

Mike