Charging the FR in the car

Craig Woodward woody at
Fri Feb 13 21:51:15 CET 2009

Is there a Wattage?  Most chargers that don't list amperage list a wattage instead.  If you have the voltage and the wattage you can determine the amperage based on that.  Watt = Volt * Amp.  So if you know the wattage and voltage, Amp = Watt/Volt.

Most car-based converts use a voltage regulator to drop the 12v current to 5v.  Since yours is rated as high as 30V, I'm betting it one of the better ones.  You may actually be able to pull an amp through it without much problem to the device, but it may get hot, or make the supply lines to the socket warm.  I'd try 500ma first and stick with that works, that should be fine.

---- Joachim Ott <jo.omsl at> wrote: 

2009/2/13 Cédric Berger <cedric.berger74 at>:
> On Fri, Feb 13, 2009 at 16:41, Joachim Ott <jo.omsl at> wrote:
>> I bought an adapter 12V => USB for the cigarette lighter in the car so
>> I can charge the FR while driving. The standard charging at 100 mA is
>> too slow. Are there any objections that I charge at 500 or even 1000
>> mA?
> Just depends how much your adapter can deliver.
> Probably 500mA is ok (even though not all adapters are made for 500mA,
> I have some chargers rated for 350mA).
> 1A is quite a lot. Might be ok, but first make sure that the
> specifications of your charger are ok for 1A output.
> (note that none of the few car chargers I have are rated for as much
> as 1A output, but most of them are old phones chargers...)

There's only the input voltage specified, 10-30V (it's a Hama 89487, 2
USB type A jacks).

> I do force 500mA with an adapter I got from an older phone. I don't
> have the exact specs of the charger, but it works ok.
> to do that (with latest kernels) :
> echo 500 > /sys/class/i2c-adapter/i2c-0/0-0073/pcf50633-mbc/usb_curlim

I use the battery package, I'll try it later with 1 A, waiting till
the led turns blue.

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