Hopefully, you guys can help me.

I'm using a car battery charger to power a windshield wiper motor. The motor is spinning a bicycle gear which is spinning a rotisserie.

My problem is that under load, it spins too fast. Would a speed controller work? I can build circuits, but I'm not any good at designing them.

Thanks for any help that can be provided.

 

search PWM circuit using a 556 timer lots around or motor speed control using PWM.

 

Hopefully, you guys can help me.

I'm using a car battery charger to power a windshield wiper motor. The motor is spinning a bicycle gear which is spinning a rotisserie.

My problem is that under load, it spins too fast. Would a speed controller work? I can build circuits, but I'm not any good at designing them.

Thanks for any help that can be provided.

Actually just hooking a 12V lamp in series with the motor might work but we'd need to know how much current the motor draws.

 

You could also try using different sized cogs on the motor.

 

Some possible bulbs, automotive types: 1129,1130, 6.4V,2.6A== 2.4Ω; 1133,1134, 6.2V, 3.91A =1.6Ω; 1143, 1144, 12.5V, 2A =6.25Ω;1156, 12.8V, 2.1A = 6.Ω
If wider range of control is desired, try a darlington power transistor like D1326, NTE2336, TIP261. TIP263, configured as emitter follower, with 1k to 5k pot for control, heat sink needed.