Lets say, for argument's sake, you had a 55 watt bulb.

55W / 12.6V = 4.36 Amps

12.6 V / 4.36 A = 2.89 Ohms

Now let's add in a "bad connection" of around .2 ohms.

Now you've got 2.89 + .2 ohms = 3.09 ohms total bulb + connection

12.6 V / 3.09 ohms = 4... Login to read more.