Re: Battery change

Posted by Owen_Dyneto On 2017/3/19 12:45:09

Similar to Packard1949, the 6-volt batteries in my '34 Packard average about 7 years before replacement. I use the heavy duty Group 4 NAPA Commercial Truck/Bus battery. Of course with the type of generator regulation you and I have, this is very dependent on how we set up the 3rd brush, and how we make adjustments to it and our driving habits depending on the driving situation.

You say you've "worked your way" thru your starter, how did your results compare with the original factory specifications:

Running free: 50 amp draw, 3000 rpm.
At cranking: 290-300 amp draw at 4 volts
Locked: 650 amp draw at 3.5 volts

A more meaningful indicator of the health of your battery than just voltage at rest would be to use a battery hydrometer and measure the specific gravity of the electrolyte in each cell - a battery in excellent condition and state of charge will give readings of 1.275 +/- 0.010