Thread: Portable solar panels and powerbanks

Phone on airplane mode should last 4-5 days if not used too much.
One spare set of batteries for the GPS should definitely last you more than a week. Start your trip with fresh batteries and I am sure they will see ya through.
A couple of 18650 batteries or a decent powerbank to run camp lights and /or charge the phone.
You could always add in a small solar panel to top up the powerbank/18650s if you felt the need. But how much extra gear do you really want to or need to carry.

Flying in and will have a base camp, its to support 4 guys worth of phones, gps etc maybe I'll look at a powerbank with the panel inbuilt