Marauderz Portable USB Power Supply

Having just bought my MS Smartphone I was in heaven, mainly because the fact that with GPRS I could get online literally anytime, anywhere.

And also since the phone came with Microsoft Messenger I could chat with everyone all the time as well!! So naturally since I'm going to be using it all the time, I'm gonna need power!!! And since the phone isn't exactly available here, I can't get no extra batteries so I'm gonna need to find other means of recharging it.

The smartphone which I got is made by HTC same nice folks that make the iPaq and the XDA. And it just happens that the smartphone's connector port (where all the recharging and synching occurs) is exactly the same as an XDAs! So I rush off to Low Yatt and I buy a USB Charge N Sync cable which would allow me to charge the phone off the USB port. Then I saw this Cigerette Lighter plug which had a USB socket in it so I could plug in the USB Charge cable and charge my phone in the car, sweet! Got that too. So I solved the power problem while in car and at my desk, I still needed some way of supplying emergency power when I was out in the field. I found a portable battery charger for the XDA which uses four AA bateries to recharge your phone while away from any other source of power, it costs RM65.... RM65 for a battery holder and a cable??? NO WAY!!!

So I get home... the USB charge cable and cigerette adapter worked perfectly, but still I had no way of charging the phone on the go. Then it hit me... the USB cable works cause it siphons off the 5V juice which the USB port provides, so if I could wire a 5V supply to a USB socket I could use the charge cable on it! I bought a 4 AA cell battery holder, and soldered it to a socket end of a USB extension cable. Wiring is simple enough.. wire the red wire to the positive terminal and the black wire to ground, the other 2 wires are the USB data channels which you don't need in this case. And I ended up with this...

4 1.2v NiMh rechargable batteries theoratically give out 4.8V, even at 1.25v each they would have a combined current of 5v so I would be safe... I guessed :P Ironically for the batteries I choose this...

It's the USB battery recharger by GP... yes... it recharges it's batteries via USB.. :P So anyway they're labeled 1.2v so they should be good. I installed the batteries in and took a reading off my multimeter... 5.45v.... Since I wasn't too sure if the variance would kill the phone I took a reading of the cigerette adapter, 5.68v... So I guess it should be ok... =D! I plugged my USB fan into the power pack... it rotated... I plugged my brother's iPaq USB charge cable in... it charged... (yes... I choose to sacrifice my brother's iPaq instead of my phone ;)) So... I plug it in and...

Well... it works... ;) Now I can charge my phone anywhere, and also I can plug in any USB based charge cable... such as lights, fans, handphone charge cables, etc. etc. I feel nice that I didn't need to buy a RM65 battery holder, but instead built it out of errr.. RM15 worth of parts? Oh yeah... if you try to make one of these yourself don't hold me responsible if it melts whatever it's powering, hey I'm no eletrician, I'm just a little crazy. :P

Article by Marauderz © 2003

Once again, Marauderz will not be resonsible for any melted phones, exploding batteries and other bad bad things that might happen if you choose to built your own based on this article