Not about paintball, but its technical (cars)

[ScatterPlot]

OK I had this idea the other day and was wondering why it wouldnt work. It is about the starter motor and alternator in a car. I was wondering if there would be a way to use the alternator as a starter motor? Possibly not the way theyre made now, but with some tinkering? Now I know this wouldnt really matter at all weight and efficiency wise, but hey why not I thought. A lot of people have been telling me that it wont work, but their explanations have either been that the battery/car/alternator is wired in series, but that could be overcome by rewiring in parallel (duh). Also it was said that where would the motor get its power, but thats from the battery (again duh). The last one was that the alternator is a weird thing with brushes to make like static electricity to charge the battery, but that sounds a little fishy to me (course I know next to nothing about cars), plus it could be swapped out with a motor thing as well. So, any thoughts?

[i heart my mag]

ok this is stupid.......how the heck is the alternator going to start the car? lol. is this a joke? cuz its very funny. the alternator is turned by the fan belt, which is turned by the motor. so if u thought about it for 2 seconds....u realize that the alternator starts spinning when the motor does........not before. so if they both spin 2gether......what are you going to do to start them spinning?? pedal?? lol the starter is totally different from the alternator....and it would b pointless to try and combine the 2 parts because the easiest way 2 do this that i could think of off the top of my head is put a coil on the end of the starter shaft. but if u think about it....since the alternator is spinning the whole time the motor is running, the starter would therefore b spinning the whole time the motor is running, thus robbing your engine of precious power because of more reciprocating mass. think next time dont be like, "umm, i have no idea wat im talking about and i know nothing about the subject but could this possibly work?" and you gave hardly any information youre like could u start an engine w/ the alternator? is that what u were actually asking??

[i heart my mag]

thank you for your time

[PolishSausage]

Re: Not about paintball, but its technical (cars)

Originally posted by bertmcmahan
OK I had this idea the other day and was wondering why it wouldnt work. It is about the starter motor and alternator in a car. I was wondering if there would be a way to use the alternator as a starter motor? Possibly not the way theyre made now, but with some tinkering? Now I know this wouldnt really matter at all weight and efficiency wise, but hey why not I thought. A lot of people have been telling me that it wont work, but their explanations have either been that the battery/car/alternator is wired in series, but that could be overcome by rewiring in parallel (duh). Also it was said that where would the motor get its power, but thats from the battery (again duh). The last one was that the alternator is a weird thing with brushes to make like static electricity to charge the battery, but that sounds a little fishy to me (course I know next to nothing about cars), plus it could be swapped out with a motor thing as well. So, any thoughts?

Won't work, motor must first be running for the alternator to work, hence having a starter.

[joez]

nope, no possible way. do you know what it takes to spin over even the smallest motor? go pop the hood of your car, and look at the battery. look at the CCA, or cold cranking amps. i personally have 2 1000 CCA batteries in my diesel, but most only have one that is generally in the 700's. the alternator puts out(depending on vehicle) up to 120 amps. the internals of the alternator would not be able to handle the power coming from the battery. that, and the alternator is not a motor.

and how would it turn the motor over, the belt? there is a reason that starters have gears, and not little rubber belts. belts slip when wet, when cold, when hot, and they break. half the time you tried to use it it would spin on the harmonic ballancer and leave you stranded. could it be done? no. and if you used the alternator to start the vehicle, what is going to charge the battery? cause when you changed the alt. to a motor, it wouldnt charge anymore.

[Lohman446]

I'm going to commend you on the thought though... here's why

On many older John Deere small tractors the generator and starter are both one unit - granted its two units combined into one, but its one less thing on the tractor. Could be why so many people have switched to a 12V system using a self exciting alternator (the darn thing is expensive), but the idea was roughly there. Never adopted it did not work out well.

GM has toyed with an idea to totally do away with the starter motor. It has to do with the computer "remembering" what cylinder is farthest upward (closest to firing) and basically hot starting the engine - dropping fuel and spark into the cylinders in correct order and starting the engine without cranking it first to get fuel and spark. There are currently some cold weather issues with the idea but you will see the starter gone in the future of automotive engineering. With no distributor and no manual fuel pumps fuel and ignition are no longer depended on the engine spinning. I know this has been as far as testing by GM.

As to the benefits of no starter... some may be there, but many starters are quite light. Then again - look at Indy Cars - they have an external starter that is not part of the car, of course this is an extreme example where a few pounds might matter.