Solar Powered Battery Chargers

[Doxtream]

I was thinking of buying a solar powered battery charger for my car so the battery will be fully charged when I get out of work. My car sits in the sun all day, why not use it. This way I could run my EV switch more hence getting even more fuel economy. What type of solar charger should I get and where? Please let me know if anyone thinks this is a good/bad idea and has had any expirences with this.

[Rolandwil]

<div class='quotetop'>QUOTE(Doxtream\";p=\"91437)</div>

I was thinking of buying a solar powered battery charger for my car so the battery will be fully charged when I get out of work. My car sits in the sun all day, why not use it. This way I could run my EV switch more hence getting even more fuel economy.  What type of solar charger should I get and where? Please let me know if anyone thinks this is a good/bad idea and has had any expirences with this.[/b]

I think you are hoping to charge your batteries that power the car, rather than the auxiliary 12 volt battery that runs the accessories, right? You would need a pretty high voltage from a solar charger, which would require either a dc-dc inverter to get the voltage up, or a whole lot of solar cells in series to get there -- larger than the roof of your car. I don't think you want to do that. You can do more, with no cash outlay, by careful driving, than by any small solar panel arrangement.

If you just want to charge up the accessory battery, you will have to connect the charger to the battery directly or else modify the connections to one of the power plugs inside the car to make it 'hot' all the time. Then there's the matter of overcharging and regulation. If you choose the solar panel just right, the 'knee' of the volts vs amps curve will do the regulation for you, tapering the charge current as the battery approaches full charge. If I were going to do it, I would be very careful.
-Roland

[Doxtream]

Thanks for the info.

[melephant]

You need a solar panel that has a cigarette lighter adapter and a power outlet modification kit from coataletech.com. The mod costs $10 plus shipping. I bought a 5 watt PV panel from heartlandamerica.com for $40. The panel must be disconnected while driving. It will only charge your 12V accessory battery. It will not overcharge the battery or discharge it at night. The major advantage is to keep the Smart Key running longer with the engine off for an extended period. I also drive with my headlights and radio on and the end of my trip home is one mile in electric mode. That means my 12V battery is not being charged up by the engine right before I shut it off. So, I am hoping for a an ever so slight energy gain at start up. It will definitely keep the Smart Key system running longer without completely draining the 12V battery. My PV charger seems to work. It certainly hasn't done any harm.

[vincent1449p]

<div class='quotetop'>QUOTE(melephant\";p=\"98591)</div>

That means my 12V battery is not being charged up by the engine right before I shut it off.[/b]

A small correction here. The 12V Aux. battery is charged by the DC-DC converter so the HV battery can charge it even in stealth, the ICE need not be running. When you are in "READY", the DC-DC converter will supply all your Aux. devices power supply so your headlights and radio are actually not draining your Aux. battery. Your Aux. battery only start to drain when you are not in "READY".

Anyway, your PV charger is certainly a good idea for those who want to store their Prius for an extended period of time.

Vincent