Kids Power Wheels Motor questions

Either that or they designed it for a motor life about as long as the installed battery.

Certainly a current-limit resistor would protect the motor. Whether the benefit would be noticeable would depend on whether _it_ was actually limiting current enough to do any good. You'd have to know what the original battery's internal resistance was and match it, you'd have to get a resistor with sufficient power dissipation capability, and you'd have to mount it where it wouldn't burn the kid (power resistors are often built to get HOT).

Not sure why it burned, but I'd expect the other motor to go also if it's a matter of you doing something wrong. Knowing if the motor really draws more current from the new batt would be nice as would the temperature rise.

Aside from that. AFAIK, lawn mower batteries are not made for deep cycle use. Maybe the batt revolted :) Maybe someone at the toy mfg can tell you more about the original batt. Beware of salesmen.

I read in sci.electronics.design that Tom wrote (in ) about 'Kids Power Wheels Motor questions', on Mon, 31 Jan 2005:

Well, maybe, but it could well have been a marginally dud motor.

Temperature shut-down is the best solution. You don't know what current is too high but you can make a better guess at what temperature is too high.

No, that would be "marine" batteries. Lawn-mower batteries are starting batteries, just like car batteries, but smaller.

My vote here is a short-life motor. The motor may have even taken the original battery down. Brushes in these things are always suspect.

I read in sci.electronics.design that Active8 wrote (in ) about 'Kids Power Wheels Motor questions', on Mon, 31 Jan 2005:

Yes, they are. That's precisely how they are different from car batteries.

That's what I thought. Lawn mower batts are charged while in use. Deep cycle marine batts are for those electric trolling ( :) ) motors and you can run 'em down. They also work good for keeping the running lights going when under sail or the anchor light overnight, but don't run 'em down 'til you can't start the diesel.

That's why I mentioned that I'd expect the other motor to go soon if the OP did something wrong. Kids around here have power wheels and I've heard no complaints of short lived motors, so OP may have had bad luck.

....

Just in case the suggestion is not clear to everyone else in the world. I think that means to measure the current with the old battery and with the new battery, assuming the user is capable. Then you know.

in

More information would be needed on the kind of motor you're using. Its possible that the newer battery has a lower internal resistance so it doesn't support well the current generated by the back emf of the motor... or more precisely the circuit doesn't.

Motors normally use 6 times more current when starting then when in operation and the normal procedure on limiting these inrush currents is using a shunt capacitor. If there is no AC conversion circuit a thermistor may be a better idea. Good luck.

OP said "lawn tractor". I should have said, "riding mower", not just "mower". I can't remember whether I've seen one in use here, but a neighbor has one you have to plug in. I think vacuum cleaner cords are a PITA enough, so it must suck to be her.

We're still burning fuel for electricity, though.

I'm taking about battery-powered *electric* lawn mowers. Don't you have them? Maybe not, because they won't mow all your acres of lawn without recharging. Suitable only for 10 m^2 European lawns.(;-)

On Mon, 31 Jan 2005 19:52:20 +0000, John Woodgate farted

current

LMAO Well thats because you are purely rubbish in your head. Do you know what a motor is or how it works?

lemonjuice and Dr. Slick are both trolls, John.

I read in sci.electronics.design that lemonjuice wrote (in ) about 'Kids Power Wheels Motor questions', on Tue, 1 Feb 2005:

Both paragraphs are utter rubbish.

Could be that the motor simply failed..

These are medium sized DC brush PM motors, geared way down. I don't see any significance to a change in impedance in the battery, the motor's resistance would be much larger, at least till the brushes start to wear out.

I read in sci.electronics.design that Active8 wrote (in ) about 'Kids Power Wheels Motor questions', on Tue, 1 Feb 2005:

So it appears. Appropriate anti-troll measure implemented.

The brushes wearing out was my immediate suspicion. In a cheap device like this is may even be the motor bearing giving it up, but I agree any battery that could supply a load like this would have a siuffifiently low series resistance that it wouldn't matter to the motor's longevity.

My point above was that a "lawn tractor" batter y was a starting battery and not really suitable for this use, though it wouldn't contribute to the death of the motor in any case.

Stick some zinc in one ear and a nail through the other and see if there is any juice. Somehow I doubt it!