[Gta04-owner] How could GTA04 shine

thomasg thomas at gstaedtner.net
Fri Mar 9 20:03:31 CET 2012

On Fri, Mar 9, 2012 at 18:31, Bob Ham <rah at bash.sh> wrote:
> On 08/03/2012 23:29, thomasg wrote:
>> On Thu, Mar 8, 2012 at 23:42, Bob Ham <rah at bash.sh> wrote:
>> > There is a panel here
>> >
>> > http://uk.farnell.com/bp-solar/msx-005f/solar-panel-0-5w/dp/654000
>> this panel generates a very low voltage.
>> The nominal voltage under testing condition (which includes cooling
>> the panel down to 298K ) is only 3V. In mediate climates under full
>> sun, you easily get 320K or even more panel temperature, in this case
>> the voltage will drop rapidly and I don't believe that you can
>> actually charge a LiIon battery with under 2V.
> The panel has a "Temperature Coefficient of Voltage per °C" of -16mV.
> That means the voltage at 320K would be 2.948V.  Assuming this
> coefficient is constant, in order for the voltage to go down to 2V, it
> would in fact need a temperature of 379K.  However, if the sun managed
> to heat a panel in the back of the phone to 106°C, I imagine the charge
> voltage would be the least of my concerns :-)

You're probably right, I should have done the math beforehand :)
Anyway, if you ever had your Neo lying on a table in the sun, you
probably know that 320K is easily reached within only minutes.
Ok, 380K is a different topic, but the Neo probably won't like the
temperatures way below that. Having the battery under the solar panel
wouldn't be very wise I guess.

> --
> Bob Ham <rah at bash.sh>
> for (;;) { ++pancakes; }
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