here's what EPEVER said btw:
"
1. Generally, we don't recommend connecting multiple controllers in parallel to charge one set battery, due to the different variance of sample, they may display different charging status when battery nearly charge full, such as one charge more one little, which is bad for your battery bank.
If you have to do so, we recommend setting the charging voltage of the two controllers to be lower than the battery's charging voltage - 0.2V.
For example, the charging voltage of battery is 14.4V, you need to set the charging the charging voltage (boost charging voltage and equalization charging voltage) of the two controllers to 14.2V or lower.
2.Generally, you need to use the USB to RS485 cable (CC-USB-RS485-150U) to do lithium battery settings, it work with the PC software ( download link is
https://www.epsolarpv.com/upload/file/1908/Charge Controller V1.95-Windows.zip).
The MT50 can set most of the control parameters for 12V lithium batteries, but not include the Lithium Battery Low Temperature protection. So, once the ambient temperature is lower than the limited value of the Lithium Battery, but the controller still charging or discharging, it is bad for your battery.
Of course, this isn't meaning that you can not use it to set the lithium battery, it's just on customers own risk, I attached the Lithium Battery parameter setting rules and recommended settings for one regular lithium batteries, just for your reference, please refer to the specification of your battery's BMS to do the adjustment.
Note: Due to the Lithium battery characteristic, the battery parameter from companies are different, and attached file is ONLY for reference, please contact the battery manufacturer to confirm whether your settings are feasible.
"
