Do you know how to find out the amperage draw of a component?
1. First measure the resistance with an ohm-meter.
2. Then go measure your battery voltage (preferably with motor running if using an alternator).
3. Divide the battery voltage by the resistance and there’s your amperage draw! It’s that simple!
Example: A typical transbrake solenoid draws 1.4 ohms resistance. 12 volts divided by 1.4 ohms = 8.57 amps! If on a 16v system, 16 volts divided by the same 1.4 ohms = 11.4 amps! You should up your wire sizes and fuse sizes when using 16 volt batteries. The formula is one of three “Ohm’s Law”: V/R=I (the other’s are V/I=R & IxR=V) and this simple check will help you decide what size fuse and what gauge wire should be used when wiring your race car.
NOTE: This test does not work on electric motors such as fuel pumps, fans, and water pumps.