Hi, I'm new here, and must admit I know very little about electronics. But I figured you guys might be able to help me.
I'm trying to sort out a way of charging a HTC hero smart phone from a bicycle dynamo (bottle) using it's mini usb function.
There are some options out there, but most either too expensive or unavailable in UK.
I've found what could be a potential winner, though - the Nokia bike charger:
Nokia UK - Nokia Bicycle Charger Kit - Specifications
I can get an adaptor that goes from the Nokia's 2mm jack to a mini-usb (from Nokia), and from my basic understanding of voltages, etc, it should do the job (I understand that when charging anything from a PC's USB, it's around 5v and 500mA (?)
Seeing as I can charge my HTC phone from USB, and the Nokia bike charger outputs 5v at 450mA, I'm guessing it should work.
Here's the blurb from Nokia:
Power generation:
Compatible with bottle type bicycle dynamos with 6V/3W and 12V/3W output
5.0V/450mA/15km/h. Maximum current 70mA
Charging starts at ~6km/h and maximum output is achieved at 25km/h. Charging stops when the speed reaches 50km/h.
Charging time depends on cycling speed, for example a Nokia 1202 with a 860mAh battery can be charged with about 20 minutes of cycling at a speed of about 10km/h (for the Nokia 1202 this would mean approximately 57 mins talk time or 74h standby time)
The only thing that worries me, though, is:
5.0V/450mA/15km/h. Maximum current 70mA
I don't know quite what to make of that. It says 5v at 450mA, but then says maximum current 70mA.
Can anyone help me explain this? Is it a mistake (maybe it should be 700mA), or does it refer to something else?
Thanks for that
Phil