Yes, but don't the proprietary batteries charge with a cable using a USB port or power point connection?

I've just bought a solar power charger that on bench testing with my cell phone and GPS tracking device (Soleus) appears to be working quite well. It doesn't need full sunlight to charge its own internal battery, which is rated at 8000 mAH, and has two USB outputs.

I bought it essentially to recharge GPS tracking devices -- which will likely be my cell phone -- on randonnees.

I will be putting it to practical use on a short overnight trip we have planned to an island national park in two weekends' time. I will report back then on how it performs recharging phone, cameras and GPS devices in varying light conditions.