hmm... I wonder if we can use solar panel to produce the electricity that the regular battery produce to start the engine. Don't have to worry about DEAD battery... at least when the sun is out.

 

well, a neat notion at least... but definitely not the kind of option for any Mazda, and certainly not for a well equipped, though definitely not luxury, RX-8...
i think the limiting factors which would make it impracitcal and unattractive to buyers is that people would almost never use it (often batteries go flat when the lights are left on, and that's usually after they turn them on at night, i would suspect; this means that the solar panels would be useless until dawn, and then need a good while after to charge the battery, WHILE THE LIGHTS ARE STILL ON...), it would be horrifically expensive for a panel large enough to generate the power needed (for an option so seldom used, at least), not to mention heavy (too heavy for a sports-sedan like the 8), and it would eliminate the option of a moon-roof or whatever ('cause putting the panel on the hood would be stupid for obvious reasons, and no room on the rear deck...)
neat premise, just impractical to excersize...

 

Your idea sparked a question for me. I was thinking that dead batteries don't really worry me, cause as long as you have a stick shift you can always push it off. I can't even count the # of times I've done that. Heck, it was the only way I could start my MG Midget for a couple of months. :p But then I started wondering, does that pushing off thing work for rotary engines? You'll have to excuse my ignorance on this, I've never owned a rotary car.

 

To answer your question, the solar recharging battery for starting the car would probably be a good college engineering project, but probably not practical in real use. The alternator does a good job of keeping the battery recharged (except in my MG) and they are small, lightweight, and pretty cheap.

One cool (literally) thing that Mazda has done in the past was small solar panels used to keep a parked car ventilated. The last generation 929's had them, but I'm not sure if they've used them in other things since then. Basically a small solar panel would power a recirculating fan that would keep the interior of the car from getting too hot. Solar works in that application, because if it's overcast or raining, it's probably cooler and you won't need the fan. That would be a cool feature for those of us in the south, so I wouldn't mind if they threw that in with the RX-8.

 

I did actually use a solar battery charger quite effectively in a previous car... simply velcro'd the 6x12 inch panel to the parcel shelf!

The thing with that car was that it was left out for a month at a time and the alarm would flatten the battery... so this worked OK... otherwise the battery would be ruined by being left flat for a long period.

That said, I don't think it is somthing that would be practical as an option on a new car... and to be honest, if you're gonna leave this car for a month without driving it... (winter???) then you really should try to get it in a garage... so there'd be no sunlight anyway...

If you're gonna leave it out for a long time, just plug a solar charge in the cigar lighter for the time it's out.

 

There's this thingy where you plug into the cigarette lighter that can recharge enough of the battery to start the car and once the car is rollin', just leave the thingy in the cigarette lighter for an hour or so, and it'll recharge the battery all the way... and there are outputs on it so you can plug in household objects into it.
It's 40 bucks, so that's a lot more practical.

 

Yes, but the solar charger stops the battery from being damaged by being flat for an extended period.

It isn't to start the car, but to keep the battery from going flat during a long term layup...

 

If your battery is completely dead I doubt a push start would work. No power for the fuel pump, ecu and ignition. Damned new fangled tech!