Solar Panels - Fuel Economy, Hypermiling, EcoModding News and Forum

Lethedethius · 07-07-2009, 02:41 AM

Hi Guys, I was browsing walmart and got this spectacular idea, solar panels on my car...(I was looking at the little stakes that have solar lights on them), I bought one and I'm thinking of splicing it into my car to power some small stuff such as the clock, and what not. Would this save any sort of gas? Would it add/relinquish any horsepower?

Christ · 07-07-2009, 05:00 AM

Nope, nope, and nope.

Well, OK... some miniscule amount... but those solar panels on the lights are extremely low-output, because they're only powering ~2watt LEDs. So you could recover (on a good, sunny day) about 2 watts... which is *2 watts = 0.00268204418 HP*.

3/1000 of 1 HP isn't going to make a huge difference.

It's a nice idea, but it's going to take a much larger scale to actually see gains from it.

Welcome to EM!

Ryland · 07-07-2009, 12:08 PM

The LED that those power is more like 1/10 of a watt, about the same as the clock, but you would be better off getting a real PV panel, they have dropped in price so much in the last year, they are down to nearly $3.50 per watt, something like a 10-20 watt panel would keep your battery topped off and could help, a yard light panel would do nothing.
Another idea, what the newest Prius is going to do is have that PV panel run a fan or A/C once your battery is charged, so you get in a nice cool car that has been sitting in the sun.

Peter7307 · 07-08-2009, 05:57 AM

Welcome from me as well.
Enjoy your stay.

Pete.

Piwoslaw · 07-08-2009, 06:46 AM

Quote:

Originally Posted by Ryland

you would be better off getting a real PV panel, they have dropped in price so much in the last year, they are down to nearly $3.50 per watt, something like a 10-20 watt panel would keep your battery topped off and could help

There is probably a thread dedicated to this question, but I'll ask it here:
If I do get a 10-20W 12V solar panel, how do I hook it up to the battery? Just '+' to '+' and '-' to '-'? Do I need any extra fancy electronics, like diodes (to me, 'fancy electronics' is anything as complicated as a resistor)? The battery needs a voltage of 14-16V to charge, right? Will the solar panel give enough?

NiHaoMike · 07-08-2009, 10:47 AM

Some solar panels should have all the required components already.

Ryland · 07-08-2009, 12:30 PM

a 10 watt panel shouldn't over charge the battery and would only need a diode to prevent drain at night.
if you go with a larger panel a small charge controller would be a good idea and having a fan as a dump load would keep your car cool on hot sunny days.

cfg83 · 07-08-2009, 04:19 PM

Lethedethius -

Here's a dude that was trying it, but I don't know the outcome of the effort :

Plugging into the SUN - MIMA Honda Insight Modified Integrated Motor Assist - 2/20/2008

Quote:

The 250 V (open circuit)panel that I built outputs 85ma of current at 180V with 56 of the mini solar panels.
The next step along the path is the integration of solar cells into the body of the Insight. The only way to put glass cells on a car body is to shock mount them so they can take some flex, and make damn sure that they will not blow off.The small 2.4" size of the mini panels allows them to somewhat follow the contour of the hood and roof.
The hood will hold 213 cells and output 17.75 watts.
The IMA pack can handle 250ma without damage. 56 cells will yield a solid 85ma at 180VDC.
3 parallel strings will yield 255ma so the hood alone
can take care of trickle charging the IMA battery.
The roof test will need to wait for a warmer day.
Aerodynamic pressures when traveling at 100 MPH can be very strong, and the cells had better not fly off.
Some interesting problems to solve, hopefully in a way that will not involve damage to the car????
Suggestions?

CarloSW2

MetroMPG · 07-08-2009, 04:28 PM

Carlos - good find. I didn't realize Mike had experimented with solar cells (haven't been to his site since... well, since he was experimenting with the e-5th wheel).

cfg83 · 07-08-2009, 05:34 PM

MetroMPG -

Quote:

Originally Posted by MetroMPG

Carlos - good find. I didn't realize Mike had experimented with solar cells (haven't been to his site since... well, since he was experimenting with the e-5th wheel).

Lethedethius triggered my brain cells to find the solar cells on Mike's Insight.

I think Mike went with the highest efficiency (but more fragile?!?!?) solar cells. Maybe lower efficiency (but more durable?!?!?) "flexible solar shingles" would be better for an auto application. This makes me think that an auto with a big flat roof would get the best benefit, aka van or minivan or station wagon.

CarloSW2