lil hot rod

[zzebby]

Frank can tell me if this should be posted elsewhere, but it is a hot rod..I think. A retired Tucson circle track guy made one for his grandkids and word got out, he made more and so I got the last one, the 12th. I call it a scaled down sprint car but he says it was called a roadster What you would see at Manzanita in the early 70's.  
Anyway the kids wore out the tiny toy car electric motors in a few days so I need to re motor it. Thinking of a car starter and a pulse modulated motor controller and a small gel cell 12V battery. Grandkids are 5 down to 2 so it doesn't need to be fast. Motor and battery need to be behind the seat so not a lot of room.
Suggestions ?

[phat46]

Your plan sounds good to me, but I know nothing about that sort of thing. I just posted to tell you that is a very cool car, no matter what you want to call it. The builder is seriously talented!

[idrivejunk]

Thats a mighty cool toy! I'd go 2 stroke personally, maybe one of these popular 50cc jobs that seem to be in all the little rods like that. I gotta wonder if a starter wouldn't be too abrupt and torquey for kids that young. Whatever you do, just try to consider all the safety scenarios that could arise and make it kid-proof.

[kb426]

Would a golf cart setup be good?

[chimp koose]

I would look for the gear from an old electric wheelchair or a mobility scooter. Compact and long use also variable speed.

[zzebby]

want to keep it electric and 12 volt, so the wheelchair or scooter is where I'll be looking. Not familiar with golf carts but I'd expect that to be a big motor. Need advice on the speed control.
Or if a starter, what is the easiest to mount and without a solenoid and simple to add a belt type pulley?

[unklian]

Something like this would work: http://www.bodine-electric.com/ProductAnnouncements/abl-3906c.asp

Basically, the motor is switched on/off to adjust the rpm.
They call it Pulse Width Modulation, or PWM for short.

[Digger]

I don't know how far battery technology has come in the last 10 or twelve years but I built a Jeep out of a golf cart for my grandson and it had 6 batteries at about 80 lbs. each but the motor is only a little larger than a starter.
I agree that a wheelchair or scooter might be the way to go.

[idrivejunk]

It just dawned on me theres a way to keep it real simple. I know you're wanting 12V and I don't know what the standard is on them but why not just find a modern second-hand PowerWheels (or similar) toy and gut that or do a body swap? I'm thinkin bang for the buck and simplicity, not to mention having most of the engineering done for you. Maybe thats a cop out, but why take chances with kids so small? The metal body is already more dangerous than say, the neighbor kids fake plastic Barbie thing. Just throwin it out there.

[enjenjo]

You might look here  http://www.monsterscooterparts.com/mobilitymotor.html

or here  http://www.monsterscooterparts.com/18voltmotor.html

or here   http://www.surpluscenter.com/Electric-Motors/DC-Motors/

[zzebby]

Thanks, lots of good info. Am looking at the pulse width modulator for speed control but still need a potentiometer to tie to the throttle pedal.
The motors that were on it were from the power wheels and the plastic gears are now toothless.  :cry:  Thus the search for improvement. The chassis and body (hand laid fiberglass) are very well built and cool so will use them as is.
Golf cart is way too much power / torque and heavy.
Wheelchair stuff is pricey.
Need a short, small 12V car starter    And add the pulse controller to it.

[58 Yeoman]

I see the scooters at garage/estate sales all the time; some are less than a $100.

[GPster]

How about the starter from a lawn tractor?  My Sears tractor tractor is probably almost 15 years old and it starts all the time (even after sitting through the winter in a cold shed) with no problem and only 2 batteries (the original battery only lasted on season).Now my tractor has a Kohler 15hp engine and the somewhat automatic transmission (forget the  name) so the battery has a higher rating. If you have the speed control figured out you might check these sources for a small starter. The number of grand kids will dictate how long you'll have to keep this thing running but you'll have to start building a car for the oldest soon. GPster

[enjenjo]

The motors that were on it were from the power wheels and the plastic gears are now toothless.

How about water jetting some new gears?

[zzebby]

Have enough projects already, trying to make this one quick and those gears made a speed of "less then walking".  Even the two year old thought it was too slow.
What starter ?