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How to make an RC-Car-Battery Powered Portable USB Charger? Answered

I recently decided that I wanted to build a "USB Battery Pack" for charging my USB devices, like my phone and camera, on the go, however, I'm pretty new to this stuff. Like, circuits and DIY electronics. So...I need help. Like, very detailed help.

I have two batteries from some old RC cars.
They're Nikko brand, 9.6 volts each, and they look like this: http://www.batteryspace.com/ProductImages/rc-battery/rc96v700h220.jpg
I also have the connector for them, with the red and black leads coming out.

What I'm wanting is charger to have is 2 USB ports, an On/Off rocker switch, an LED for On, and an LED for Low Battery.

But I have no idea where to start, what to buy, or how to connect what to buy.

So I'm asking here. There have been plenty of tutorials for usb chargers on here and Youtube, but none close to what I want to make.
If the batteries I have wouldn't be as efficient, please tell.

If anyone could help, I'd appreciate it! 



8 years ago

I think that your best bet would be to use a multimeter to find how much resistance is needed to reduce the voltage to 5 v. Put the switch on the positive lead. I don't know of an easy way to detect low voltage without using up lots of power. (There is a way... it's just not something that I can easily explain over the net.)

Maybe someone else in the ibles community might know of a better way than I do... I'm more of a IT and AV guy myself...

They have some pretty cheap chargers out there... unless you're looking for the experience of building it yourself, I would just go and buy one if I were you.