In LA

I have an extra cell phone battery or two lying around, and have occasionally been on long flights that would have felt less long if my iPod could have played a few extra hours of video. I’ve noticed there are some commercially available devices that can charge an iPhone for sale on the net, but they are either expensive or are a little bulky due to their use of AA batteries. Wouldn’t it be cool if I could just use small, high-capacity, and cheaply available lithium ion batteries to act as an emergency battery pack for my iPod and other devices that charge over USB?

I’m in the process of thinking this through, and my knowledge of electronics is rudimentary. Here’s my current line of thought:

1. Whereas, iPods charge from a USB port, and
2. Whereas, USB provides 5V at 100mA (up to a max of 500mA, thus saith maxim in APPLICATION NOTE 3241 Charging Batteries Using USB Power), and
3. Whereas, my extra treo battery provides 3.6V (at ?mA), and
4. Whereas, many auto USB chargers for iPod currently on the market do not work with iPhones,
5. Now, Therefore, I would likely need to step-up the voltage from my Treo battery, and hopefully get sufficient amperage out of it. I do not know the reason that many chargers on the market do not work for the iPhone/Ipod Touch, but it does look as though other folk have figured it out. I’m going to pore over those ladyada forum postings and try to understand their fix for the problem before I try to build my own adapter.

Anyways, a fun project to think about. I’m at the thinking stage now, will write more if I actually take any action on this.

This entry was posted on Tuesday, December 11th, 2007 at 11:25 pm and is filed under Apple, Geeky, Treo 600. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.