I am trying to put in a secondary LiFePO4 battery in my car that powers a car refrigerator. I want it to work like a UPS that switches to battery when the car is turned off but while turned on, it charges and powers the refrigerator simultaneously.
From what I was reading, a standard parallel circuit to a DC-DC charger can cause problems.
I am looking for a product that a similar design as the diagram below.
What product do you guys recommend that can do something like this?
Thanks in advance.