Quote:
Originally Posted by GregWeld
Relays are more about the capacity of the switch - over the voltage/amperage some load sees. Given the proper gauge wiring etc. The relay is just a switchable switch (I like that term).... but it doesn't raise or lower the voltage.
If you compare the wiring gauge on an older car - and then run it thru an old pull style switch - not only are you possibly reducing the voltage (contact switch) you're also arcing etc... that was fine with the old T12 headlights... but now we want to run big old nasty big watt jobbies.... NOW you need a relay and some appropriate gauge wiring to handle that load. If not - you'll overload the stock wiring - and you'll burn up the switch. Ditto an electric fan. You want the fan to get heavy gauge wiring - they can pull 30 amps momentary (start up load)... and you're switching them on via a short to ground thru the temp/switch. That's when you use a relay... to have the switch switch the switch....  It takes barely anything to switch the relay - and then the fan sees full voltage.
I'm only tossing this out there - because about 90% of the guys I know - still do not understand a "relay".
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Correct that voltage is not affected, amperage is affected. Voltage is like horsepower, amperage is like torque. Also correct that given proper wire size, a relay is not needed. Problem is when you need a 12-14 guage wire to power a window motor or headlight, and you have to pass through a switch with contacts equal to 22 guage, you have a built in resistance. The resistance will eventually build to the point it will stop the flow of electricity and the motor will quit. If held on long enough the switch and or wire would get hot and eventually fail. The relay bypasses this built in choke by attaching the 12 guage wire directly the the power source and turning the switch into JUST a switch, not a power feed.
As far as the motors electric life uses, I have not looked a set carefully, but if they are the imported motors and not Delco units, they are weak out of the box. I am pretty sure they are the same motors used the 4th gen camaros and if anybody has owned one of those long enough, they have replaced the craptastic window motors they used. The aftermarket ones worked great for a few months, but then start getting slower and slower until they just quit.
We just started selling Nu-Relics and installing 2 kits in the shop right now. One in a 68 camaro, and one in a 70 Firebird. So far I am happy with them. Once we have some feedback in these cars we will either start selling them or continue looking for another option.