Posted by beesh on May 7, 2009, 2:42 pm
Nice soltution for a Solar Laptop Charger .
Posted by David on May 10, 2009, 9:21 am
known fraudulent trader takes your cash delivers nothing
Posted by Eeyore on May 10, 2009, 4:16 pm
They're a joke. A friend's Dad bought a PV solar panel to stop his car
battery self-discharging during periods of non-use. It couldn't even
manage that. I reckoned he needed 2 m2 of panels just to do that alone
throughout the year.
Posted by Guus W on May 11, 2009, 12:16 pm
Does this friends dad has a hummer with all the lights on? ;)
2 m2 panels gives more then 200wp or 16,6 amps at 12 Volts (when the sun is
Normal self discharge is (with european cars) not more then 0,1 Amps, so a
panel of 1,2 Watt is sufficient to compensate that.
A panel of 0,02 m2 would be sufficient (gives 2 watts - 0,17 amps)
Posted by Eeyore on May 11, 2009, 2:25 pm
Guus W wrote:
And nothing when it isn't. In the UK here winter insolation falls as low as 0.5
kWh / m2 / day
so a 15% efficient solar cell would generate 150Wh if 2 m2. That's 11.9Ah at
12.6V and about 0.5A averaged over the 24 hours of the day. OK, maybe 1 m2 and
250mA would do. Don't forget the car's electronics in additional to
What for about half an hour a day ?
TOTAL insolation is what counts over a 24 hour period you twit.