Thread: Rocking Granny Wiper Motor power problem

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This year I made a Rocking Granny prop from the Scare FX how to webste. For some reason my wiper motor doesn't have more than one speed, fast. I am powering the wiper motor with a 12V 6amp battery charger, to slow down the wiper motor I purchased a 12V DC speed motor control. Everything was working properly on the speed motor control when we measured the volts when it was hooked up to the battery charger. When we connected it to the wiper motor the amps coming from speed motor control was only .5amps to 1amp. You could hear the motor humming but it wouldn't turn at all. Any suggestion to solve this problem would be appreciated.

Dave

Is it an older wiper motor or a new (er) unit ? Sounds like it's not getting enough juice......

I'm not an expert by any means but I did learn this season that some wiper motors won't even turn with less than .5 amps, and under load I would think it would need more than that. I've never used a speed control, but one solution might be to try to get hold of a 5v source which would slow the motor down.

I built one of these last month and I'm using a PC power supply to run it.

Try using the charger with a motorcycle battery you are lacking the Amps you need to power the wiper motor . Last question do you know what the wiper moter is from ? if so vist your local libary and look up in the wiring book the Wiper motor and it will show you both speeds and using what Terminals you need on motor.
Anything more let me I'm a master tech at Volvo and use many wiper motors for props .

Your 12V 6amp battery charger should also have a 6v on it switch the button over to that and it will slow it down. Also reverse the wires and run the motor in the other direction. Sometimes you get a different speed that way. How many wires are coming from the motor? not the control box on the motor but the motor it's self. If you can see 3 you have a low and high speed and a ground.

Sounds to me like your speed control unit is only set up to put out 1 amp