Generator question

I've noticed that the generator light always stays on when my 190Db is running. I checked across the battery to see 12.55 volts with the car running. What should I be seeing across the battery with everything running? Thanx in advance.

[psfred]

Minimum 13.1 V, battery won't charge on less.

I'm a little rusty on generators. Could be a simple as a stuck brush, could be a bad voltage regulator, and I don't remember how to check them.

Dig up someone familiar with older tractors -- they all had generators.

Peter

[leathermang]

Smart farmers either have diesel tractors or get a magneto for their gas tractors ( which makes its own electricity when turning)... then just park in the barn and charge the battery every night... the heck with that generator light.....

[dabenz]

Here goes, according to my mid 1960's Chilton manual:

Bosch regulator part no. RS/UA 160/12/15
Cutout Relay cut-in voltage 12.7-13.4
Cutout Relay reverse current 2.5-6.5
Hot Regulator current 17.5-20.5
Open circuit voltage at regulator 13.8-14.6

Bosch generator part no. LJ/GEG 160/12/2500R9
Field Resistance 4.8
Brushes considered worn at less than 18mm
One brush holder should be grounded and the other insulated.

Since your battery voltage is 12.55 I'd assume the generator is going bad. Test the regulator first, to be sure.

Usually you have to disassemble the generator to get at the generator rear bushing. Leathermang gives sage advice. Your car is 12V so compare the cost of 12V alternator and regulator against 12V generator rebuild (if you can find someone in your area) and regulator. The work for a 12V-12V changeover is a no brainer, since you don't have to change light bulbs and rewire the starter.

I forgot: Most generators don't charge at idle. If the battery voltage climbs when engine speed is increased and stabilizes when engine speed is stable then I'd check the battery. It may be bad to the point where the battery is consuming more than the generator can put out, even with a good generator. Isn't as much margin as compared to an alternator.

I just went out and hooked up a multimeter to the car. I then started the car and went back under the hood to rev up the engine and watch the meter at the same time. The generator is working properly. It built up to 13.2v and held there. It appears that the light was not hooked back up correctly. Many thanx all.