Nu Relic power window issue

[colorado80439]

So I've installed a complete set of Nu Relics power windows in a 69 Camaro coupe and I have to say I'm pretty impressed. There is one issue I've been trying to solve. The door windows power/roll down too fast for my liking. Up speed is fine and quarter windows are awesome. I've spoke with the folks at Nu Relics, they are helpful but do not have an answer. I installed a 10K potentiometer rated for DC, which slowed the window speed but burned up in the process. I think I'm on the right track with a variable resister to control the down speed, just not having much luck finding the correct product.
I'm thankful for all the help I've received from everyone on this site.
Thanks again

[Spiffav8]

I too was a bit surprised by that when mine where installed.

[dhutton]

A resistor is going to affect the power available to raise the window. It’s not a good idea imho unless you get clever and place a schottky diode in parallel with it such that the resistor is bypassed by the diode in the up direction. 10k is pretty far off the mark imho, I think you are probably looking for something less than one ohm, certainly less than 10 ohms. It also needs to be rated for high current, around 20 amps.

The kit I installed in my 69 Camaro several years ago did not drop quickly but the ones I have installed recently do have that characteristic. It seems they changed something....

Don

[colorado80439]

Oh ya the old schottky diode trick, lol. Thanks Don, I guess I have no concept of resistance because I have no idea what voltage drop it will take to marginally slow it down. I'll let you know what I come up with! Thanks gain

[dhutton]

Oh ya the old schottky diode trick, lol. Thanks Don, I guess I have no concept of resistance because I have no idea what voltage drop it will take to marginally slow it down. I'll let you know what I come up with! Thanks gain

Well, those motors draw around 20 amps. A .5 ohm resistor will drop the voltage 10 volts. Going down the current is likely lower, but you get the idea.

Voltage drop = Current x Resistance

Don

[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]

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

[blitzer454]

Hmm, I use the New-Relics power windows in my car and they only draw around 2A when moving up or down. When the window hits one of the stops the current will shoot up. I have my over-current limit (stall) set to around 3A on my automatic up/down circuit.

I don't recall that they gave the current limit specs when I purchased my motors, I wonder if they did change to a different motor.

I think you are right that the low load is window going down, high load is going up and stall is when the window reaches one of the stops.

You probably should design around the 5A low load spec when choosing the resistor, but know that current can get as high as 20A if you leave your finger on the switch too long after the window hits the stop.

I would shoot for a variable resistor under 10 ohms rated for 300W or more. Like the AVE030020E8R00KE (https://www.digikey.com/en/products/detail/vishay-huntington-electric-inc/AVE030020E8R00KE/270002). Try it without the diode first you might get lucky.

[dhutton]

Oddly enough I’ve had 30 amp fuses blow with my Nu Relics power windows...

This always help me understand electricity....

Don

[colorado80439]

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

[colorado80439]

Hmm, I use the New-Relics power windows in my car and they only draw around 2A when moving up or down. When the window hits one of the stops the current will shoot up. I have my over-current limit (stall) set to around 3A on my automatic up/down circuit.

I don't recall that they gave the current limit specs when I purchased my motors, I wonder if they did change to a different motor.

I think you are right that the low load is window going down, high load is going up and stall is when the window reaches one of the stops.

You probably should design around the 5A low load spec when choosing the resistor, but know that current can get as high as 20A if you leave your finger on the switch too long after the window hits the stop.

I would shoot for a variable resistor under 10 ohms rated for 300W or more. Like the AVE030020E8R00KE (https://www.digikey.com/en/products/detail/vishay-huntington-electric-inc/AVE030020E8R00KE/270002). Try it without the diode first you might get lucky.

Thanks for chiming in!
I haven't seen that variable resistor in my search, it's reasonably priced so I bought it for testing.
I'll reply with the results

By the way, any issues with your window speeds?

Thanks again

[dhutton]

You are a glass alignment god if you only need 3 amps to raise and fully seal repop glass on repop weatherstripping.... :hail:

Don

[blitzer454]

By the way, any issues with your window speeds?

My windows are quick but I don't feel they are excessively fast.

You are a glass alignment god if you only need 3 amps to raise and fully seal repop glass on repop weatherstripping....

Okay I went back and double checked my measurements and I did screw them up. I have my over current A/D count value set to 0x200 (hex) which translates to 2.5V (10 bit A/D counter with 5V reference). I was mistakenly taking that voltage value as the current forgetting that I have a voltage divider on the A/D channel such that 5V scales to 30A. So 2.5V is actually 15A. On a side note I have the rear window over-current set to 0x115 which translates to 8.11A. Sorry for the confusion.

So I guess the Nu-Relics spec values are actually pretty close to what I'm seeing in the real world.

I would like to say that my windows are perfect, but they're not. They like to leak around the seal at the top of the window when I hit them with the water hose, but they're not to bad in the rain.

[dhutton]

My windows are quick but I don't feel they are excessively fast.



Okay I went back and double checked my measurements and I did screw them up. I have my over current A/D count value set to 0x200 (hex) which translates to 2.5V (10 bit A/D counter with 5V reference). I was mistakenly taking that voltage value as the current forgetting that I have a voltage divider on the A/D channel such that 5V scales to 30A. So 2.5V is actually 15A. On a side note I have the rear window over-current set to 0x115 which translates to 8.11A. Sorry for the confusion.

So I guess the Nu-Relics spec values are actually pretty close to what I'm seeing in the real world.

I would like to say that my windows are perfect, but they're not. They like to leak around the seal at the top of the window when I hit them with the water hose, but they're not to bad in the rain.

You should have taken the glass alignment god title and ran with it… :D

Don

[colorado80439]

I purchased the variable resistor and tested at several settings and 1 ohm gave me 1 volt drop which seems to be a perfect speed, that was at a battery voltage of 12.5 so it may be a little faster with the alternator turning. I have a 1 ohm 300watt resistor picked out and I will need a diode.
Not sure what Schottky Diodes to purchase looks like I need to know forward current, reverse repetitive voltage, forward voltage, forward surge current, and reverse current. I'm assuming I should look for the known values of 12-15 volts, and 20 amps. Any input would be awesome.
Thanks
https://www.mouser.com/ProductDetail/284-HS3001RJ

[dhutton]

Blitzer is the expert but I would shoot for minimum 30 reverse volts and minimum 30 forward amps. Forward voltage should be as low as you can find. The rest of the specs won’t make any difference imho.

Don

[blitzer454]

Don's specs are good, I would only add that I would find one that is physically big enough to work with and high surge current rating. I would go with the SBX3040-3G (https://www.digikey.com/en/products/detail/diotec-semiconductor/SBX3040-3G/13154204) as it meets all the requirements and is also cheap.

For the resistor the FVE030020E1R20KE (https://www.digikey.com/en/products/detail/vishay-huntington-electric-inc/FVE030020E1R20KE/269987) would get the job done for less money.

[colorado80439]

Awesome! It's so cool and fortunate to get this kind of assistance, I will follow up with my findings
Thanks again

[Ketzer]

Fascinating thread...I dont understand a single word of it...but am amazed by what you guys are talking about and the fact that you found a solution!


Jeff-

[colorado80439]

I ended up using this resistor
https://www.mouser.com/ProductDetail/284-HS3001RJ
And this diode
https://www.digikey.com/en/products/detail/semiq/GSXD080A004S1-D3/5068422

They both qualified for the parameters we were looking for and the packaging was convenient for mounting.

The front windows now work at the same speed up and down.

Thanks again for all the awesome assistance

[dhutton]

I ended up using this resistor
https://www.mouser.com/ProductDetail/284-HS3001RJ
And this diode
https://www.digikey.com/en/products/detail/semiq/GSXD080A004S1-D3/5068422

They both qualified for the parameters we were looking for and the packaging was convenient for mounting.

The front windows now work at the same speed up and down.

Thanks again for all the awesome assistance
Those are some serious parts. You know what they say. Go big or go home…. :)

Don

[XLexusTech]

I ended up using this resistor
https://www.mouser.com/ProductDetail/284-HS3001RJ
And this diode
https://www.digikey.com/en/products/detail/semiq/GSXD080A004S1-D3/5068422

They both qualified for the parameters we were looking for and the packaging was convenient for mounting.

The front windows now work at the same speed up and down.

Thanks again for all the awesome assistance

Nice. any chance you can put up a quick draw of how its wired? Which feed which side of switch ect..

[colorado80439]

Sure I can verbalize it easier than a drawing, but the switch has 2 wires to the window regulator motor. One up and one down, the resistor is put in series with the power down wire and the diode is in parallel with the resistor. I had to play with the diode direction to get it correct.
Thanks