Re: 1932 903 battery not charging

Posted by Owen_Dyneto On 2014/3/17 22:22:14

Still waiting to hear what happened when you temporarily grounded the field wire. And here's two other thoughts to think about.

(1) Unless you have an extreme diet of short 2 or 3 mile drives between starts or constantly use a vintage vacuum tube radio which draws large amount of current, a 10 amp charging rate is more than adequate for daytime driving to keep a battery fully charged. I keep my 34 rate at about 7 amps for daytime driving and increase it via the 3rd brush if I'm driving at night. The only time I use a battery charger is after winter layup.

(2) Yes, using a 2nd ammeter to validate the reading of the car's ammeter is a good idea. But not in series with the battery cable!! Those Dyneto starter motors can draw 250-500 amps so if you use a meter with that +/- range, you won't be able to differentiate 10 from 20 amps and if you use a meter with a smaller range you cook it to toast. Either put a +/- 30 amp meter in series with the existing dash meter, or in series with the main body/chassis feed which is taken from the starter relay, or better yet, right at the generator output from the regulator. In addition to ammeters with direct connections on the back, there are also meters which simply lay across the wire and use the magnetic flux to indicate current direction and amperage.