Hi I’m having a similar issue. I recently bought the powersolar 24W for a trip and I’m having the same issues you have mentnioned. I’ve tried charging a few items, but I don’t seemt to get much more than a few minutes of charging with a blue ring before it turns red, and then the device stops charging.
I was under the impression this red ring meant it was too bring or too hot, but I can only assume this might also include insuffucuent lighting as well?
I’ll hold out for another week or so and see if the better UK weather helps but I’d be interested to know if you have gotten any response from Anker about this or found a solution/reason for this issues?