I want to give a portable 60 watt panel my daughter to keep her Garmin InReach powered in the event of SHTF. It has a built in USB port and I know it easily provides USB at 2 amps. I've tested that. But that's only 10 watts. I am going to connect it to a cheap MPPT controller and see how much I can get for charging some LiFePO4 batteries. I'll report later