Hi all,
First off, great forum! Am a noob at electronics and schematics and would really appreciate some help starting my solar panel project.
I hope to be doing some serious hiking next summer in Belarus and Poland but need my Samsung Galaxy Tab phone for GPS assistance (I know its big but need to take it to do some internet-related things also). I will need to charge it somehow whilst hiking so naturally a solar charger looked like a good solution to charge the 4000mAh battery in my phone. The problem is most portable solar chargers with battery will output 5v at about 0.5A current. Assuming I can find one with a 4000mAh batterypack it would take more than 8 hours to fully charge (correct?). This is most likely too long as I'd probably need a full charge every day.
So maybe it is possible to build a 1A solar charger with battery myself using things from ebay. Ive been looking at other tutorials but haven't been able to find a comparable project. I have though found the following parts:
- 5W, 12volt, 0,35 ampere solar panel,
- a 3.7v 4000mA replacement battery flatpack for Galaxy Tab to store power,
- USB connection to deliver power form battery to phone.
I'd love to get 2A output but have learnt this is unrealistic using a 5W panel (5W = 12V x 0.35A, so 5W = 5V x 1A should be doable reducing the chargetime).
I know i need to regulate the power from the panel and protect the battery from overcharging/discharging. Let me know if you can guide me in my quest and I'll buy you a beer!!
Cheers, Fred
EDIT: My phone charges at 500ma through USB and 2000ma through wallplug. I believe USB cannot deliver more current, is this correct?