Watts.

[nibs]

Can any one tell me what the rated watts would be +/- for a small PM motor which draws 3.5 amps when running, no load, powered by a 10 amp battery charger (42 watts?). Am wondering if these motors would power a lawn mower blade. They are off walk behind powered golf bag carriers, running at 12 V. Am trying to learn and now have a dead craftsman riding mower that I want to turn into an elec, has to be low budget.

[Patrick]

Watts = Volts X Amps. So we need to know what voltage you were using to determine the wattage.

Just for reference, my Black and Decker lawn mower draws 12 amps at 120 VAC = 1440 watts.

1 HP = 746 watts, so my mower is producing about 2 HP.

My guess is that your motor is too small. And remember you need that blade to spin at about 2500-3000 rpm to be effective at cutting grass.

[TomEV]

The watt rating for golf bag motors normally ranges from about 50 to about 150 watts. Unloaded, your motor is using about 42 watts as you indicated. I imagine it is rated at about 100 watts (about 1/8 hp).

There are a few electric mowers here, and they tend to use motors in the 750 - 6000 watt range. (1 to 8 hp) with riders using heavier motors.

[nibs]

Thank you for that folks, dreaming is what I was doing. I want to use one motor for the drive wheels and two others for the mower deck.
Some years ago I gave away the 24V massive airconditioner fan motor from my ex greyhound bus, I could prolly get it back but it is in Utah.
Looks like the drive motor needs about 2 or 3 hp and each of the blades needs at least 2hp.

[TomEV]

Glad to help. And no worries about addressing 'Roxy'. She likes to answer EV questions as well!

As an aside, you may want to post the question to the main part of the board - Right now this thread is a sub-thread to the Open Source DC Motor Controller thread, and doesn't have good visibility. The site admin folks can probably have it moved.