15-10-2024, 06:34 PM
(This post was last modified: 15-10-2024, 06:35 PM by "Slack Alice" Simon.)
Resistance = Voltage over Current R = V/I
Let's guess the wiper motor takes 2 amps, and you want to drop 6 volts (from 12 to 6)
Resistance required is 6/2 = 3 ohms
The drop is lost in the form of heat, resistors are rated in Watts, Wattage = Volts x Amps = 6 x 2 = 12 watts
I would use something with a greater wattage rating.
I have a 4.7 ohm 50 watt resistor on the shelf, which I would try first - erring on the cautious side, and remembering the amperage was a guess.
If I didn't have a resistor, the standard bodge is to use a bulb as a resistor - if I don't have a 6 volt charger and need to charge a battery, I stick a 6 volt headlamp bulb in series and carry on.
You are welcome to the resistor if you think it would do.
Try a bulb first, to see what sort of result you get.
Cheers, Simon
Let's guess the wiper motor takes 2 amps, and you want to drop 6 volts (from 12 to 6)
Resistance required is 6/2 = 3 ohms
The drop is lost in the form of heat, resistors are rated in Watts, Wattage = Volts x Amps = 6 x 2 = 12 watts
I would use something with a greater wattage rating.
I have a 4.7 ohm 50 watt resistor on the shelf, which I would try first - erring on the cautious side, and remembering the amperage was a guess.
If I didn't have a resistor, the standard bodge is to use a bulb as a resistor - if I don't have a 6 volt charger and need to charge a battery, I stick a 6 volt headlamp bulb in series and carry on.
You are welcome to the resistor if you think it would do.
Try a bulb first, to see what sort of result you get.
Cheers, Simon