Solar panels in gasoline car

Hi Peter,

A very good suggestion which has got me thinking early on a Sunday morning.

I don't know what a typical alternator loads an engine by but it goes from a large amount (that you wish to reduce) just after starting on a cold winter's morning (rear heated window on, lights on, heater blower going) to a very small amount (summertime, after having been driven for a while). Unfortunately this is the issue you will likely face - there is probably little solar energy when the reduction in loading would be most beneficial. To get real benefit might mean replacing the heavy alternator with solar but that would make the car too restrictive in seasonal/geographic use; and supplementing the alternator with solar might have a very minimal benefit whilst increasing drag, weight and cost??? Just some thoughts - although they seem negative please don't stop exploring the idea.....ideas are always good...technology wouldn't have progressed otherwise !

Another thought is that your idea is loosely similar to where an RV or underutilised car adds a solar panel to help charge the battery....they have some heavy loads or infrequent charging and adding 'free solar' energy into the battery helps keep it topped up and ready to go.

Rod

Interesting idea, but.

One things is produce additional electricity with solar panels, whatever during drive or during car waiting somewhere. But for reducing looses on alternator, you would need think of disconnecting alternator. And disconnecting of it for maximum saving need to be done on mechanical level. Then you are introducing whole new bunch of problems, and probably will not work efficiently. Of course, you could only disconnect load from alternator, but you still need have any way of connect alternator in days or hours, where would not be enough of Sun.

I just bought 150 Wp flexible PV panel, which I am to plan to mount on my ICE car. And add some extra battery and a lot of other electronics to measure of efficiency of charging via Sun on car.

In standard life car is not usually parked on the most sunny places, which would be very welcome with PV system on car roof. When I will be ready to show more results, I will post there too.

First of all, an alternator can use up to 30% of a car's power to run.

I also mean connect them both. In theory replacing an alternator would be possible if the solar panel was powerful enough, but then you could only drive in the day time.

Solar panels could help reduce fuel consumption and it is even possible to run vehicles solely on solar power. It is mainly a question of how much to spend versus how much is the benefit, including factors like reduced emissions. A car might generate 20 KW to maintain highway speeds. A 150 W panel is less than 1% of the cruising power generated by the engine. If the electric energy is charging a battery even when the vehicle is not moving, it could provide (replace) a more significant fraction of the power on trips.

I would love to see transportation systems designed specifically to use solar energy - it is possible with today's technology.

So essentially it isnt practical on a car unless the size of solar panels reduces or unless the entire horizontal surface of the car is solar panels

If you could use solar power to reduce fuel costs by 0.5% and a solar panel lasts 3 years, to make it cost effective, the cost of your solar panel should be less than 0.5% of your fuel costs over 3 years.

Standard Poly/Mono crystalline PV panels costs about 0,5 €/Wp. From 1 m2 you can get about 140 - 160 Wp. But those framed PV panels are not good choice.

Better is use flexible panels, but they cost about 1,5 to 2 €/Wp. Efficiency is similar -  140 to 160 Wp/m2. You could easily up to 2 m2 on car roof - about 300 Wp on roof. This give you somewhere about 450 to 600 € per roof with flexible PV panel.

But than you need another components (cables, charger, some control and safe devices, ...), and easily you are in 1 000 € price level. This give you about 700 l of petrol - and this is (with 7 l/100 km) about 10 000 km of full consumption.

But with saved consumption on alternator (let say up to 10 %) is 100 000 km return of investment. And this is not covering any necessities of alternator disconnection improvement.

Result - only with saved fuel make no sense to do it. But with other attributes to consider - learning something new, saving environment, curiosity, ... it is interesting experiment.

I thought general rule of thumb was 1% degradation per year

Good point. I was just assuming a 1 year warranty and tripling it. In an automotive environment I would expect other failure modes than just efficiency degradation. The numbers can easily be reworked to reflect any better assumptions.

Very good point and thanks for valuable info.