How To: Make a rechargeable, solar-powered USB battery

Make a rechargeable, solar-powered USB battery

An emergency battery charger for your mobile phone comes in handy, but it's not the ultimate solution; once it's dead it's useless (what a waste). If you want to really get off the metaphorical grid, you can follow the steps in this video to construct a more robust circuit that will not only bail you out of an inconvenient situation but also recharge in between uses. The simple addition of a low voltage solar panel and rechargeable batteries makes this possible. Enjoy!


4 x NiMH AAA Batteries
1 x 4 AAA battery holder
1 x Small PV (photovoltaic) solar cell
1 x Diode rated min 5V 500mA
1 x USB cable or cable of your choice

Tools Required:

Soldering Iron
Lead Solder (the kind with flux core is best)
Heavy Shears
Wire strippers
Electrical tape


Solder in a well ventilated area on a non flammable surface
Check the circuit polarity before final soldering

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My phone is now ready for the coming Armageddon or my next camping trip, but at this rate, I'm not sure which will come first.

Bit stoned sounding... explanations were kinda ok. Overall, cool use.


one concern I would have about a device like this is the possibility of feeding too much voltage into the device. I would say you might want to test how much power output the battery plus solar panel has in direct sunlight. I have been looking for a way to power my gps unit on my bicycle when the internal power gives out and this might work.

i trust your skills instead could you make me one ?what if your stuck in snowy cold place will iy work ?what if it gets wet then what?

The theory is relatively sound, in practice however it does not work. The cellphone needs 5V whch the battery supplies. The battery however needs at least 5V to charge. The PV panel as illustrated in the video only supplies 0.1 volt. As we can see the panel consist of a single wafer which under full sunlight can only supply 0.5V. You will need at least 10 of these to make it work. From personal expierience 11 wavers or a combination of panels producing 5.5V is adequate. Please also consider the 0.6 voltdrop across the blocking diode.

please, someone refine this project and report. Thanks.

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