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  View original topic: Volt-a-drop West Coast Metric
Jeler Sat Jan 30, 2021 11:03 am

Hello everyone

I just volt a drop from West Coast Metric and there are no instructions.

I have a 66 bus wired for 12 Volt now, with a 6 volt wiper motor.

Has anyone every installed/used one of these?

https://www.westcoastmetric.com/i-22967761-w-2612.html

I all ready know I can get a 12V motor but want to keep the 6V motor.

Thanks
Jeff

Eric&Barb Sat Jan 30, 2021 12:21 pm

Voltage goes into the voltage drop and from the voltage drop to the wiper switch. Voltage drop is just a resistor, and gets VERY HOT when you run the wipers. So you need to mount it in such a way as to not let your fingers accidentally touch it or something flammable like paper not to come in contact with it that will cause a fire. Other problem with using a resistor is it reduces voltage more when it is first turned on, when hot it will allow more voltage thru later. This means you will probably need to set voltage output a bit low when the resistor is cold and when warmed up a bit high. Resulting in wipers a bit slow at first and a bit too fast later. The clamp in the center is how the voltage can be adjusted.

Personally have switched to a adjustable buck module. Figure about 8 Amps to run the wiper motor and double that at start up. So the 15 Amp units with 20 Amp momentary ability works. Nice to be able to have it set to 7 volts output all the time.

https://www.ebay.com/sch/i.html?_from=R40&_trk...p;_sacat=0

Also added a PWM to allow adjustment of the wiper motor speed from really slow to as fast as it will go with voltage available. Again really need 15 Amps or more.

https://www.ebay.com/sch/i.html?_from=R40&_trk...15+amp+PWM

Had to reroute the ground wire in the motor out to the PWM module to get it to work. Plus since it is an open circuit board with no casing, I made a bracket to mount the PWM module to the front of the package tray. This keeps the module from shorting out and allow air to pass over the heat sink to keep the electronics cool.

telford dorr Sat Jan 30, 2021 2:12 pm

Quote: I just volt a drop from West Coast Metric and there are no instructions.
Well, it's just an adjustable resistor. The sliding middle contact can be moved.

I'd move the slider to the far end of the resistor, then power up the wipers. Move the slider towards the other connection until you get 6 volts (or half of whatever the battery voltage is) across the motor. Once you get it adjusted, tighten the slider down so that it can't move.

Mount the resistor somewhere that it can get good air flow around it, as it will get hot.

Jeler Sat Jan 30, 2021 2:29 pm

telford dorr wrote: Quote: I just volt a drop from West Coast Metric and there are no instructions.
Well, it's just an adjustable resistor. The sliding middle contact can be moved.

I'd move the slider to the far end of the resistor, then power up the wipers. Move the slider towards the other connection until you get 6 volts (or half of whatever the battery voltage is) across the motor. Once you get it adjusted, tighten the slider down so that it can't move.

Mount the resistor somewhere that it can get good air flow around it, as it will get hot.

Telford

That's exactly what I was looking for. Does it matter which wire goes where? In and out on the circuit.
I was thinking of mounting it on the crossbeam right above the fuse box and far to the left to keep it away from other wires or flammables.

Thanks again
Jeff

Jeler Sat Jan 30, 2021 2:30 pm

Eric & Barb

Thanks for the info.

Jeff

Eric&Barb Sat Jan 30, 2021 2:49 pm

Jeler wrote: Eric & Barb

Thanks for the info.

Jeff

Glad to help. The wire spiraled around inside that resistor has resistance to electrical flow, causing the wire to heat up. Electrical flow direction does (edit) not matter to that resistant wire.

Jeler Sat Jan 30, 2021 3:13 pm

Eric&Barb wrote: Jeler wrote:
Thanks for the info.

Jeff

Glad to help. The wire spiraled around inside that resistor has resistance to electrical flow, causing the wire to heat up. Electrical flow direction does matter to that resistant wire. Eric Barb
Eric Barb

It does matter? Or does not matter?

Thanks jeff

Eric&Barb Sat Jan 30, 2021 3:37 pm

Jeler wrote:

It does matter? Or does not matter?

Thanks jeff

Sorry, does not matter.

Jeler Sat Jan 30, 2021 3:44 pm

Got it, thank you!
Have a great weekend



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