hamburgler wrote:
On a different note I spent another hour in the garage tonight and tried a few things. I noticed that the positive cable at the battery gets really hot when the fan is only on at high speed. It will get hot withing 20 seconds. I also tried high beams only, fog lights only, heated seats only and that didnt seem to affect how hot the cables get.
I really dont think its the cable anywhere because there doesnt seem much resistance from the earlier voltage drop tests I have done. There must be something else making the cables hot?
I also wanted to add that I dont get any spark when I touch the negative battery cable to terminal. All batteries ive played with in the past show a big spark when hooking it up.
voltage between pos and negative was now about 12.1
The engine cooling fan draws a lot of current (at least 20 amps, if not up to 40) so if there is a bad contact it will heat up.
The only thing that heats up cables is resistance combined with current flow (unless they are close to an external heat source such as a hot exhaust system) -- assuming you are conducting these tests with the engine off. The resistance can come from a wire sized too small for the load (unlikely), broken wire strands underneath the cable sheath, or more typically corrosion at the terminal. Corrosion at the terminal can be between the terminal and mating contact or where the wires are crimped inside the terminal. The heat generated at a terminal will travel along the wire as copper is an excellent heat conductor.
The lack of spark when hooking up the battery cable may be a symptom of high resistance in the terminal crimp or simply that most of your accessories are off and that there is no electrical load when touching the battery cable to the battery post.
If you find a particular wire that is warm, try running an additional large wire in parallel with the warm wire and see if that helps. Please let us know if the terminology we are using is unclear or confusing, there are many ways of explaining this and we may be making the wrong assumptions about how you are interpreting our instructions.
Just out of curiosity, how are you measuring voltage drop along your wires? Where are you placing your voltmeter's electrode tips?
RT