Removing components off engine belt.

[NoCO2]

I had an idea earlier today and I just want to see your opinions on the feasibility of this mod and what kind of advantages I might see from it.

I am thinking of buying a solar panel and mounting it on either the roof or trunk of my car to replace my alternator as the source of power to recharge the battery. My main question is, what kind of improvements in engine efficiency would I see from removing that off the belt, but keeping the A/C and Heat (I can't do that much surgery). The other question is, how effective do you think it would be at charging the battery and how long do you think the battery would last if a solar panel was connected. That last question actually builds on this one though, how strong of a solar panel would I need to get? Just a 12V one or is there a certain Amperage I should look for?

I am just trying to get an idea here of how doable this is, nothing really set in stone or committed to it yet. Any advice/help/information that you guys can give me would be very helpful.

Thanks.

[SVOboy]

I would poke around and find darin's thread about alternator removal since he deals with most of the issues. You should get a deep cycle battery because solar won't likely be an end all replacement, but it will work to trickle charge a bit.

Have you thought about removing the power steering (if you have it)? I don't have that or a/c and I'm happy.

[NoCO2]

I would love to, but I'm not that mechanically inclined. I thought the Alternator would be pretty simple though since that is just taking something sitting right on top of everything, out, and then running a shorter belt and hooking the leads to the solar panel to the battery (or batteries to get more millage from it) and then running the leads from where the alternator was connected to the stuff in the car, to the battery so everything still has power. On paper that doesn't sound too hard, but knowing my luck it would end up being hard.

How hard is it to disconnect the power steering? I can live without that, the A/C I can't really live without though because I use it to defrost my windows, but I never run it otherwise.

[rbhollabaugh]

The solar panel won't replace the alternator. Period.

[Frank Lee]

Defrost works fine w/o a/c in my area.

[trebuchet03]

Originally Posted by rbhollabaugh

The solar panel won't replace the alternator. Period.

The all or nothing attitude results in the latter Semicolon.

[Coyote X]

If you can get a lot of panels on the car it is possible depending on how you drive the car. If you swap to LED lights and drive mostly in the daytime with lots of time for the battery to recharge it might work.

The idea that I might do on my xfi project is do the large solar panels but leave the alternator on the car and just turn it off with a switch. That way if you need to drive at night or longer distances you can turn the alternator on and keep driving. When it is off it will be a tiny load on the engine only.

The way I thought about doing it was using a lexan sheet and lay over the trunk lid and heat it to form the proper shape. Then cut away the trunk except for the outer edge and replace it with the lexan. Then just put the panels under it to protect them from damage. Might take the entire trunk lid and maybe the hood to get enough panels to break even with a minimal load with the engine running.

[jjackstone]

Hate to say it guys but the solar panels just won't help very much. You might try Peltier devices if you have a whole lot of money to burn. Here's a link to one experiment.

http://www.hi-z.com/websit07.htm

There are other experiments out there. I think the technology is probably still cost prohibitive though.
JJ

[SVOboy]

There's a guy out there with a solar powered scooter that charges while sitting around, so if he can do it I'm sure a low-load car with decent sun exposure and lotsa panels may be fine,

[MetroMPG]

Coyote is on the mark by saying: "it depends".

To the replies stating "categorically, NO!": I have driven my car a fair bit on a solar PV charged 12v system. Not with car-mounted panels, but by depleting the battery for local driving, then recharging via PV when parked (including aiming the car at the sun so I could leave prop a panel up in the windshield).

You can get away with smaller PV area, as Coyote says, if you drive infrequently and have lots of time between battery depletion for recharging (my situation).

If you're trying to size your array to generate the necessary amount of power to run the car without depleting the battery, then it becomes much more challenging.

An 80 watt 20v consumer grade panel is about 8 square feet. You'd need two of those at a minimum just to support the electrical demands of the engine - ECU, fuel pump, injectors, occasional brake & signal lights (no other electrical accessories on, including lights, wipers, radio etc.). And they'd need to be perfectly aligned to the sun to generate their peak power. Change any of those factors, and you need even more panels.

Check this thread for more info
Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

And
http://metrompg.com/posts/alternator-optional.htm