Comments on: DIY 9V Battery USB Charger

By: Tech Wizard

Tech Wizard — Fri, 26 Aug 2011 20:41:00 +0000

this is posted a number of times.
its simple, and charges any USB device, if you add a 200 ohm Resistor to the center (data) pins to provide 2.5v, otherwise the Apple products may not all charge.
2nd, i would add multiple 9v in series. this ups the current (amps) as opposed to parallel wiring which ups the voltage. this basic device charges very slow as is… so it needs a couple hundred milliamps to charge faster.
and yeah, it could be a bit of an expense if you just use 9v batteries to charge devices, but you can also use a 9v adapter (power supply transformer) that you may already have kicking around.

By: Wiety

Wiety — Tue, 25 Jan 2011 00:36:07 +0000

Not a very good design for:
1. There are too many power losses due to dissipation. I bet the glue will melt down.
2. Expensive, u’d better use rechargeable battery.
3. too small capacity

By: Jopp

Jopp — Thu, 28 Jan 2010 19:51:37 +0000

Not a smart design. The transistor will get very hot after a while. Better use a voltage regulating IC.

By: Mark

Mark — Mon, 04 Jan 2010 15:31:45 +0000

This is a 9v battery to 5v usb charger to charge usb devices, not a 9v battery charger.

By: Paul Levene

Paul Levene — Wed, 02 Dec 2009 10:28:02 +0000

It says do not recharge on the side of the battery!!! and for good reason.