Alt. not charging battery... Help

[whytry]

I have a problem. This is what I have. I am running a Powermaster 100 amp alternator, 65 amps @ idle, 1 wire alt. I have been using this alt for 6 months, of which the last 3 the car has not been running or such short distance not noticed....

My battery is in the trunk - 4 gauge wire to the starter. 8 gauge wire from alt to batt. All seemed to work fine. I am changing to larger wires just to make sure.

I recently put in a TKO-600 and drove it around over 20 miles and I noticed my voltmeter gauge was at approx 10 volts!!! I drove it home and when I got to the house it died on me, and gauge read 9 volts!!! Needless to cay I had to charge the new Optima Battery up to get the car into the garage. I double checked that the power wire to the batt from the alt. was not cut, and it was not. I check batt and alt with voltmeter and read same level after charge 12.0 when I started the car. Had my buddy kick the RPM's up to 2500 and the alt did not kick it 100 amps. It used to, but not anymore. I replaced the alternator today after talking to Powermaster and they swapped it out for me. The new one is doing the same thing. Any suggestions on what to check next?

FYI - The wires are all solid 1 peice wires, not several wires soldered together,and are multistrand Monster Cable wire..... The ground runs from the battery to the frame, then I piggybacked another ground terminal from that ground to the motor - starter bolt, underside of motor......

Please help

[Pro-touring towncar]

Have you checked voltage both at the alt and at the batt. I take it you have a long run of 8 guage from the alt all the way to the batt. You may be having voltage drop. How are you measuring the amps? A normal running rate of charge should be about 13.5-14.4 volts. The TKO install shouldn't affect accessory drive being the engine is still turning all the accessories at the same speed. I have heard of some charging problems with underdrive pulleys, but not an underdrive tranny.

Tim

[gmachinz]

I think you may have a bad ground design somewhere. The battery charges throughthe negative side so if you are only getting 12.0V at the battery, I'd say either the ground system is at fault or the one-wire alt. is the culprit-whcih, if you check out www.madelectrical.com you would understand the drawbacks of the one-wire alts. I would temporarily re-wire it back to a standard type with the internal regulator before swapping out another Powermaster and see if it solves your problem. Also, make sure your ignition switch is actually engaged on the "charge" circuit-if it isn't or if the switch is faulty at that connection whether it's inside the switch or in the wiring itself, it could cause the alternator to not charge. -Jabin

[whytry]

Well thanks guys, I tried everything you listed and nothing changed dramatically. I regrounded the car, from the battery ground to the engine ground all to bare metal again and it improved a little. I went out and got some new cables, all 2 gauge from battery and 4 gauge from alt to starter solenoid and now everything is fine.... Nothing changed, I went from Monster cable wires to the same wire used for arc welders and now I am happy as a clam!!!!! Thanks for the help. I do think my ground was a big part of the problem... Thanks all!!!