Quote:
Originally Posted by dcdoug
So if I wanted to wire a resistor in parallel with the ignition bulb circuit as a back up in case the bulb burns out, what ohm rating should the resistor be? I've seen 560 ohms referenced elsewhere. Sound right?
|
No. You want a 15 ohm resistor. Now, at 14 volts a 15 ohm load will draw a little under one amp and make a little under 14 watts. So, order a 15 ohm, 20 watt resistor off Amazon. Here:
[ame="http://www.amazon.com/Watt-15R-Wirewound-Cement-Resistors/dp/B0087ZDBW4"]2x 20 Watt 15R Wirewound Cement Resistors 20W 15 Ohm 5%: Single Resistors: Amazon.com: Industrial & Scientific@@AMEPARAM@@http://ecx.images-amazon.com/images/I/311j04URzIL.@@AMEPARAM@@311j04URzIL[/ame]
You don't have to wire it directly around your alternator light, unless it's convenient to do so. All you have to do is route it to the voltage regulator and the ignition switch just like the light is wired. You can test it, of course, by disconnecting your alternator light and running your car. If you're getting over 13 volts then you know it worked.