I am working on a project where I am switching between a solar panel and a 20 volt, 5 amp AC to DC wall adapter to charge a 12 volt lithium iron phosphate battery. I am using a Morningstar Duo solar charge controller to safely charge the battery. However, when I connect the wall adapter to the controller it draws up to 7 amps (when it is only rated 5 amps) and causes the supply's voltage to drop.
Now it appears that the PCB board on the battery is damaged.
Anyone have any insight on what might be causing the problem or how to safely limit the current being drawn.
Thanks a lot everyone who takes the time,
Link to charge controller: