MPPT Charge Controller - Method to reduce charge current between 0C to -20C?

Q&A and troubleshooting
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I’m looking for MPPT charge controller that can work with LFP batteries capable of charging at a reduced rate at cold temperatures. Specifically batteries from this brand: https://www.relionbattery.com/products/lithium/rb20

I know the SmartSolar MPPT or BlueSolar MPPT have settings to adjust the charge current limit while actively in use. However, the system I’m working on doesn’t have a way to communicate with the charge controller when in the field.
This Q&A addresses a similar issue Mppt: Reduce charge current at low temperature - VictronEnergy via registers set over the VE Direct or hex protocol. Specifically:
“Low temperature charge current” and “Battery low temperature level”

I would like to know

  • If “Low temperature charge current” and “Battery low temperature level” are during assembly will those settings be retained by the charge controller even if it is power cycled?
  • Is it possible to configure the charge controller to have two temperature limits? One to reduce charging before 0C and -20C and another to prevent charging under -20C?
  • Are there any alternative ways to accomplish derated charging based on the internal temperature of the MPPT charge controller?
  • Is it possible to disable bluetooth on the SmartSolar device via the V.E. Direct protocol?