Nu Relic power window issue

[colorado80439]

So if this is correct
watts=amps x volts, I need a resistor to handle 300 watts at least

If E= IxR then 20 amps at 10 ohms would be a 200 volt drop?

I think there will be some trial and error to determine the correct resistance.
I would try a variable but they are over $300 for that power rating

I'll start with .5 ohms and see where that leads

According to Nu Relics low load is 5A, high load 11A, and stall is 20amps
I'm assuming low load is window down mode and high load windows up.

Thanks Don, let me know if that doesn't add up

[dhutton]

Originally Posted by colorado80439

So if this is correct
watts=amps x volts, I need a resistor to handle 300 watts at least

If E= IxR then 20 amps at 10 ohms would be a 200 volt drop?

I think there will be some trial and error to determine the correct resistance.
I would try a variable but they are over $300 for that power rating

I'll start with .5 ohms and see where that leads

According to Nu Relics low load is 5A, high load 11A, and stall is 20amps
I'm assuming low load is window down mode and high load windows up.

Thanks Don, let me know if that doesn't add up

Pretty much all sounds right.

Also, Watts = amps squared x ohm

Or power = I^2 x R

Your load on the resistor is very short term so you will be able to get away with a power rating smaller than the calculation would tell you.

You can make 1 ohm putting two .5 ohm in series and .25 ohm placing two .5 ohm in parallel...

Those up down currents foreshadow the problem I was predicting, the voltage drop will be higher going up than it is going down and the window won’t raise properly. You can try the Schottky diode if you find that to be the case.

Don

[colorado80439]

Originally Posted by dhutton

Pretty much all sounds right.

Also, Watts = amps squared x ohm

Or power = I^2 x R

Your load on the resistor is very short term so you will be able to get away with a power rating smaller than the calculation would tell you.

You can make 1 ohm putting two .5 ohm in series and .25 ohm placing two .5 ohm in parallel...

Those up down currents foreshadow the problem I was predicting, the voltage drop will be higher going up than it is going down and the window won’t raise properly. You can try the Schottky diode if you find that to be the case.

Don

Great advice, again, Thanks Don