I have one that I use for other activities. First time flying I thought I'd use it to recharge batteries. Got 1 battery completely charged and about 1/2 another before it shut down due to low charge remaining. As someone else pointed out, the solar panels are basically going to be to slowly recharge the unit, although I've been able to run a Peltier effect cooler while camping to get an extra day or so out of the ice. Remember that it is lead acid battery technology (glass mat) so even a deep discharge isn't much more than a few volts' drop.