55 watts divided by 12 volts equals 4.58 amps. You need to allow for a surge of about 10 percent, so .4 amps plus the 4.58 means a 5 amp fuse should be good for each 55 watt light. But since you no doubt will run the two front lights from a single switch then a 10 amp would be fine, and you could go to a 15 or 20 (the max capacity of the switch). DO NOT OVERFUSE AND USE THE PROPER SIZED WIRE FOR THE LOAD.
Use the same formula to calculate the load of your rear work light.
Now for the $64 question - where exactly will you be getting the power for the switches?
- Straight off the battery? (bad idea and you can accidentally leave them on when you turn off the tractor.
- Straight off the ignition switch? (real bad idea as the ignition switch isn't built for that kind of continuous current)
- Via a relay (the best idea is the relay is picked by the switch, which is in turn powered by the ignition switch. The relay then switches current to the lights directly from the battery).
Use the same formula to calculate the load of your rear work light.
Now for the $64 question - where exactly will you be getting the power for the switches?
- Straight off the battery? (bad idea and you can accidentally leave them on when you turn off the tractor.
- Straight off the ignition switch? (real bad idea as the ignition switch isn't built for that kind of continuous current)
- Via a relay (the best idea is the relay is picked by the switch, which is in turn powered by the ignition switch. The relay then switches current to the lights directly from the battery).
