Helping a friend work on his race car and he recently switched to a 16 volt system. Currently wiring up an electric fan & popped the fuse on the relay system. Is there a way to choke the voltage down to 12 volts, like a resistor or something? I know there is a box for stuff like this, but trying to stay away from that $85, if possible.

Thanks

Say you want to drop 16 volts down to 12 volts and assume the fan draws 20 Amps continuously. You'd need a resistance of 2v/20A = 0.10 Ohms. The power rating of the resistor would have to be 20A * 20A * 0.10 Ohms = 40Watts.

How big was that fuse the popped? Startup current will always be higher than running current. The 20A running example I gave probably will draw at least 30A for less than a second at startup. A circuit breaker might be a good alternative way of feeding the fan. Many OEMs now days simply use an appropriately sized fusable link for things like fans.

It was a 25 amp fuse. We were just hooking to the battery to make sure we had it working, using the toggle override wire.

I appreciate the help.

Thanks