4 weeks ago, 'Orange' the mobile telecommunications company, (not sure if they have a U.S presence)approached gotwind.org to make a prototype of their wind powered mobile phone charger, being developed at Texas University, but they are a bit slow building a prototype apparently,I just had to have a go, wasn't sure if I could do it.
The brief was to charge a mobile phone using wind power,with a blade diameter of no more than 12" and for the unit to be mounted on top of a dome tent for the upcoming music festivals, in this case Glastonbury next weekend.
A quick check on reresource.org suggested I could generate about 1 Watt in a 10 mph wind at this blade diameter, this seemed reasonable.
I decided to charge 2 NiMh (2000mA/h)AA cells within the black control box from the mini generator, and then I had an efficient booster circuit designed and made to up the 2.4 volts to a constant current(600mA) 5.5v supply.
It works well, however, as expected it takes around 24 hours to charge the AA batteries, which would charge a typical mobile phone from flat in about 1-2 hours.
I think I have managed it, and Orange are happy, just waiting for the cheque now..
A good article here
http://www.newswireless.net/index.cfm/article/3426
Cheers
Ben.
