Need a quick backup battery for your phone? You can make one of these backup phone chargers from just a 9V battery and the guts of a dollar store car charger.
I found this particularly clever because it’s not obvious that to charge a 5V device, one might take a part a 12v charger and substitute a 9V battery — but it’s the the dollar store electronics that do the voltage matching. Very nice.
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Read More at: BuildATruckCamper.com: $3 DIY Emergency USB Phone Charger From An Altoids Tin
