Solar Prius

It is getting close to time to replace my 1998 Honda Civic. One of the cars on my short list is the Toyota Prius. There has been a lot of talk about plug-in hybrids which, unlike the current Prius, are not powered by gasoline alone, but are plugged into an electric socket to recharge the batteries and then run on electric power alone for as much as possible.

The current Prius keeps the charge of the batteries somewhere in the middle and never seems to charge them completely nor let them drain down completely. I think that is the most efficient way to keep a charge on the batteries and also avoids complete charging cycles which shorten battery life.

So the problem with a plug-in is that you will need to top off the batteries and probably run them down much further in order to run the car solely on electrical power. This will shorten battery life. Also there is some inefficiency in using coal to produce electricity and then use the electricity to charge a battery and then use the battery to run the car. You lose a little power with each step. Additionally, by using electricity you are just transferring the pollution from the tailpipe to a powerplant somewhere (which would at least help Atlanta’s air).

So it occurred to me that instead of a plug-in hybrid, it would be better to put solar cells on top of the car and charge the battery that way. One reason this occurred to me is because my car is parked in the sun all the time, whether that is at home or in the MARTA parking lot.


One guy put a bunch of solar cells on a plate and attached that to the top of his car, ruining the aerodynamic shape of the Prius. Another company has a kit that is about $4,000 that fits the roof better, but adds a lead-acid battery to hold the solar charge. They claim the cost can be offset by tax credits, but only when you combine that with a solar electrical system for your house (which qualifies for the credit by itself). With that logic, you get a credit for buying a Hummer and a system for your house. The extra battery powers the car for a few miles before the car converts back to a regular Prius (so you don’t mess up the built-in batteries), but that means you are carrying around a big battery and it adds to the cost. Ideally, the solar cells would charge the car’s batteries directly. Yet another company sells two strips that install on the roof, but this $1,600 system (plus labor) increases overall mileage by 10% at best. Someone calculated that it would take 427,000 miles to recoup that investment with gas at $3.

Something else that is a great idea, but nowhere near ready for prime time.

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