SpudFiles

does any body know what i would use to control a 12v dc motor?

what do you need it for, like what is it going to power.

a speed controller, a reciever and a transmitter. you can get it all at your local hobby shop, but it wont be cheap. maybe $250. chech ebay. if you need more detailed help let me know.

i am looking for something cheap. can i use a potetiometer?

Pots vary in how much variance they have. There are definitely ones that work though, since there are fan controllers on computers.

ok so i am going to use a starter motor or a fan motor from a car on a minibike frame. i wonder if a could rig up one of the electric trolling motors used for troll fishing?

You can't use a pot to control a motor that size you'll end up melting it.

Go with a normal R/C type car setup.

Michael

What range of speed do you want. If you want a full range of speeds then you will need a speed controller, but that is going to be difficult to make or buy for a starter motor as it draws a lot of current.

If you want only 2 or 3 speeds then you could make your own resistors and wire them to SPDT switch. Note that this is probably not the best option, it it not efficient at all and produces a lot of heat which will probably melt your resistors.

any idea how long a deep cycle marine battery would last? i geuss for speeds i will have a low and a high .

Making a regulator that'll control a starter motor powered by a 12V automotive type battery is going to be really expensive. IIRC, a starter draws a couple hundred amps, not something your run of the mill electronics can handle.

Your best bet is to just use a low voltage switch to control a starter relay which in turn controls the power to the motor. You might be able to scrounge a starter relay for cheap from a junk yard. Or here is one for $6.50 rated at 225 amps.

Only two speeds; "full power" and "off".

I don't think starter motors have a very high duty cycle, so be careful or you might burn it up pretty quick.