$15 Solar Panel?
 

So I've seen these 15-20 dollar solar panels around that plug straight into the cigarette outlet.... I've been reading a lot on alternaters and saw someone say that adding a solar panel to a stock setup can help mpg by making the alt not work as hard as usual....
So would one of these solar panels actually help mpg this way? AND do it just through the power outlet?
Any info is appreciated cause I can't find this exact topic or answer...

I think that would depend on how charged the battery is when you park the car and how much it further drains while parked--I really doubt that they would make an appreciable difference while the engine is running.

My other concern is over-charging the battery.

You could probably install an alternator kill-switch and try to figure out how long the car will be parked, how much that would charge the battery, and so how far you could drive and still fully charge while parked.

If I did install an alt kill switch, would it be able to charge well enough through the outlet? I guess i just don't trust it to be able to charge well but it should... I've never had good experiences with cig outlets lol

You might want to look at this thread and others.

http://ecomodder.com/forum/showthrea...ent-16119.html

Those small panels are more like a maintainer not really for recharging. Also your outlet must be energized with the key off for it to work.

The power output of those is quite low, even in full sunlight. If you have it somewhere inside the car chances are that it will be in the shade or turned away from the sun most of the time. Even in fair weather you cannot expect more than one watt on average.

Then there is the weight of the panel. Probably less than a kilogram, but not really nothing. The panel will just generate a few Watt per kilo. In comparison, the ICE produces about 500 Watt per kilo or more.
Adding the panel will most likely raise your fuel consumption ever so slightly, and will definitely hurt performance a tiny bit.
It is the same problem as the exhaust heat recovery systems have; too heavy for the tiny amount of power they produce. In general they can barely make up for their cost in stationary, continuously operating installations. Logic forbids they could break the odds in a car, where weight is a penalty and operation is usually limited to a few hours a day or less.

The solar array could be used to charge your battery when the car is resting. Sadly, not in this setup.
The cigarette outlet will be switched off once you remove the key. Otherwise it could keep the battery charged, but not now.

As has been said before, it is best to put solar arrays on your house and charge your car batteries from the mains.

The problem isn't so much the limited 10A capacity of the outlet, but in the performance of the PV panel itself. They don't supply much current to begin with, and if they aren't pointed directly at the sun, which is constantly moving relative to the car, then the output is a fraction of the rated output.

There is no worry of overloading the cigarette outlet, but I can't imagine the charger would do much good. The main benefit would be keeping the battery of a car that isn't driven often enough, topped up and in good condition.

After being disappointed by a 1W panel that had a defective diode 6 yrs ago (used to avoid a reverse current flow)...I'm having good luck with a 5W panel ($35) bought thru Amazon.

Does not need a controller....does not overcharge the battery....but puts out enough current to build the battery back up after using a 12V air compressor to refill an air tank.

The seldom driven vehicle is also sitting in partial shade....panel is under the windshield.

Keeps me from needing to put a charger on the battery every 2 weeks or so.

Why buy thru Amazon? Mostly the reviews...4*s and many reviews means a product has been around a while and it works. If you can find a better price with free shipping...go for it?

these are cheap, I have no personal experience with them. but have heard good things. Sale! Unique High Voltage Solar Panel (3 x 25)-Electronic Goldmine

I have this one:
Sale! 6 x 12 15V Glass Solar Panel w/Wire Tabs & Frame-Electronic Goldmine

I put it on the back of the sunvisor and wired it to the hot lead of the dome light. It doesn't directly increase fuel economy, but it makes me feel better about coasting home at night. I know that the partly-drained battery will recharge the next morning. I park facing the morning sun! The panel will also recharge a dead battery enough to start an engine. Of course it'll take a few hours, but it will do it.

http://img.photobucket.com/albums/09...mes/solar1.jpg
http://img.photobucket.com/albums/09...mes/solar2.jpg

I use one of the cheap HF ones in the Cherokee. I have a pretty significant electrical draw that will kill the battery if it sits for 2 weeks.

With the solar trickle charger, it was able to sit 2 weeks and start under it's own power. The battery was still pretty low and it cranked slow, but it did start under it's own power. Usually after sitting 2 or 3 weeks, I would have to pull the battery and throw it on the charger (I don't own any jumper cables)