And the saga continues, the conclusion.
1991 Laser, 1.8LStep 1
- Old battery was a Delco, bought it 2002
- Second battery, had a Mopar label, but suspect it was Exide, about three years of life. Both batteries spewing liquid, much corrosion on car. Just replaced battery with brand new Exide battery, over rated for this vehicle, more CCA (525, car requires 430).
What I found on the drive home. Install of new battery, before cranking engine, voltage is 12.6 volts. After cranking engine with, engine running, 14.36 volts
2 minutes after starting, battery voltage is 14.19 volts. With a Fluke DVM connected to the battery, for 27 Km, battery voltage varied between 14.09 (at a stop light) to 14.21 at 70Km per hour, no load beyond engine draw. At idle with full current draw (rear window defog, head lights and blower) battery voltage was 13.86. Idle voltage with no current draw (beyond engine and driving lights) was a battery voltage of 14.09 volts. Time to recovery from a full load idle was about 1 min. Air temp was about 25 degrees C. It should be noted that I was also monitoring the "sense" voltage (on a second meter) at the alternator (voltage reg input), and that voltage was about .5 volts lower, but followed the battery voltage, and never changed beyond always being about ,5 volts less than the battery. For 27 Km the monitored battery voltage never exceeded 14.35 volts.Step 2 Attached a third DVM, to monitor the current output of the alternator (250 amp shunt installed in series with the output). With the day time running lights and, always on, side markers, disabled (removed fuses), the current from the alternator was 15 amps (seems high to me). Moved the shunt to the battery, current into the battery was 5 amps at start but was decreasing to 4.16 after about 15 minutes (idle speed). Battery voltage was now about 13.70 volts. Manual says when the regulator operates above 60 degrees C that the reg voltage is 13.4 to 14.6. The alternator housing containing the regulator was to hot to hold your hand on. At no time during any of this testing did the battery voltage exceed 14.5 volts. And for the record, the "key out of the ignition" current draw was, 125 milliamps. So, unless I can find some other problem, my best guess for an answer is, "two bad batteries, with the same fault".
Test instruments tell me that the system is operating normal, the only variable was the battery. After about 50Km of driving there is no sign of fluid leakage from the battery. At no time did any of the three batteries feel warm to the touch. The second battery (Mopar) had a specific gravity reading in the "white " zone between green and red, but this could have been because we had added water. The first battery was sealed and un testable.
I now know more about batteries and charge systems than I ever wanted to know. Now I just need to know how to stop all the battery acid corrosion. I have washed everything with baking soda and water, but it still seems to be corroding.