Does a solar charger work?

Following the link Windstrings posted, the solar panel is indeed 6.5 WATTS. I had a couple of big solars on my cruising sailboat that put out about 5.5 AMPS each in full sun when oriented directly at the sun. ANY shadow across the panels would reduce the output by up to half as would an incidence angle to the sun. These panels were the rigid type, bought in 1997 for nearly $1000 each. At that time flexible panels were less efficient. By now efficiencies may be better and prices lower. In the tropics they worked very well and, because they put out about 15 volts, I used a 3 stage regulator to keep from overcharging when we were away from the boat and not using much electricity. I also had a sophisticated insturment that measured current in and out of the battery banks as well as voltage and state of charge.

6.5 watts would produce only half an amp at maximum efficiency, less when the angle is not optimal or it is cloudyand nothing from dusk to dawn. Would this be enough to keep the Prius battery charged? Anyone know what the exact current drain is when the car is parked?

I just love being a member of this forum, what a great source of information.

Thanks to all of you for your contributions.

 

No typo, Watts, not Amps... In terms of current, I agree- around 500 mA under direct sun is achievable with really good solar panels, drop that to about 300-350 mA under the Prius' solar-absorbing glass, even less when the sun is not directly overhead or if there's cloud cover and subtract the ~30 mA drain from the vehicle electronics, and you get maybe a few Watt-hours per day in the summer, generally less.. This won't recharge a severely depleted battery, but it should be sufficient to maintain it for a good while..

That's why I say that you need a minimum of a 5 Watt panel for in-car, under-glass use.. Those little 2 Watt portable jobs won't even offset the parasitic drain of the vehicle electronics..

 

wow... you're absolutely right!.... I was just testing you! :huh:

I must be getting really goofy.. sorry about that major mistake!.....

Humm.. 6.5 watts.. that changes things a bit... the ones that do more cost quite a bit.

I'm not super impressed at the effieciency of these.. size per watt ratio......

Well 6.5 would prob do the job since there is no load on it and it would be getting the charge very often.... turn off your fob switch etc......

Its funny what your mind sees verses what your eyes see... thats getting scary!