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How come my 94' bonne' eats alternators? There's probably been like 30 different ones put in, in like a year =/

Are you buying new, reman or junkyard alts? Who is installing them and do they have the correct knowledge to do the job? Do you have a pissed of ex girlfriend that cast a voodoo spell on your car? J/K It sounds like there may be other things wrong to go through so many alts.

There is obviously something else going on there that your "alternator exchangers" (what I call most so-called auto electric shops).

I would bet that you have an intermittent short somewhere that is draining your battery and/or frying alternators.

Find a competent auto electric shop and tell them they need to look for a short in your system. It will be more complicated if it is intermittent, since they will have to test each wire while moving it.

I've had this occur on vehicles before, but a real electrician will be able to find it and/or search out the culprit.

30?? you should have stopped after 2 or maybe 3 to diagnose the problem. have you replaced the battery and checked the wires?

bonnevillain wrote:30?? you should have stopped after 2 or maybe 3 to diagnose the problem. have you replaced the battery and checked the wires?

Batterys been replaced by force (car started to go crazy one day in canadian tire parking lot so i put one of their piece of *shoot* batterys in it)
Wires have been checked.

I install the alternator myself, I don't really like other people touching the mechanical side of my car.

30!?

something is definitely not right

I rebuilt alternators for a living years ago. I can honestly tell you that you have a problem in your electrical system. If you went through 2 or 3 a year like I used to I would say put in an optima red top and be done with it. A battery acts as a buffer for the alternator during times of high amp draw. The bigger the better and 1000 cranking amps is best. There are only two things that cause alternators to go out. They wear out or they are overworked. Since yours isn't wearing out, it is being overworked. I always say "Follow the electricity." check the amp draw from the battery with the ignition switch in the off position. I don't know for sure but I think it should be in the milliamp range. This is for things like keeping the memory in the computer and radio clock and presets. If your car is drawing multiple amps, something is wrong. The next thing would be to turn things on one at a time to check the amp draw from the battery for each item individually. With the engine and everything possible turned off but the ignition switch on, check your amp draw. This powers your fuel pump, sensors, relays, dash lights, etc. I would expect this to be a fairly low number of amps. If it is high, you can pull fuses to isolate the culprit. After that, use the previous amp reading as a base line reading and begin testing the things you can turn on. Begin turning on then back off things like the engine, brake lights, parking lights, low beams, high beams, driving lights, radio, turn signals, AC, etc. To figure the expected amp draw for your bulbs, use W=V*A.

Example, a baseline amp reading of 3 amps. If my low beams are 55w each and 2 parking and 2 tail lights are 7w each. Thats 131 watts for the six bulbs divided by 12 volts from the battery with the engine off, equals 10.92 amps added to the reading taken as a base line will give you the reading of 13.92 amps. This is an example. Use the formula, not my numbers.

The alternators in these cars are crap. They can't handle the load very well. They are only rated for about 100 amps which means that under normal conditions they are only putting out about 50 to 75 amps. Also, with the engine off you should have about 12 volts. With the engine running you should have about 13.5 volts. When you find your problem circuit/s you should check all connections INCLUDING GROUND and look for scuffed or broken wires. Remember that everyone forgets to check the ground connection at the other end of the ground strap from the battery. Another quick and easy check is to see if a fuse for an item that is turned off, sparks when it is removed or inserted. I believe the answer will be found in a scuffed wire or a bad ground.

rcissna wrote:I believe the answer will be found in a scuffed wire or a bad ground.

X2

BTW rcissna, nice write up and instructions! There should be no reason why our cars should eat through alternators unless a person has some huge power bass amp or something. I have had cars that ate alternators and it was always a short (scuffed wire) or other unusual draw (bad or loose ground) that did it.