is 0.4A sufficient for charging?

Alexander Lehner lehner at edv-buero-lehner.de
Tue Jun 23 08:09:19 CEST 2009



On Tue, 23 Jun 2009, ivvmm wrote:

> going to buy a device from a local store that will convert alternating
> current from my bicycle's front hub dynamo to 5V 0.4A. Is that
> sufficient for charging my Neo?

I have soldered such a device by myself and it works. I think the phone 
needs only a little more than 120mA for charging, depending on which 
features are powered on (GSM, Bluetooth, WiFI, GPS etc).
The main problem that I see is, that the FR will not recognize the load it 
may pull from the USB line if you don't put that magic resistor between 
the Id and GND pin of the  USB plug.

You can also use the power_center tool to force a charge of 500mA, but I 
believe it falls back to 100mA as soon as the power supply drops (what 
will happen if you stop bycicling). So a battery-buffered solution would 
be preferable.

BTW: Could you please send a link to the shop where you found this DC 
converter?

Alex.




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