British generator again

rrlund

Well-known Member
Since I'm using classic and my other post has gone to page 2, I'll start a new post. I got that multimeter figured out just enough to be dangerous. I think I've got the generator charging alright, but I need somebody to check my work. The battery was still up OK this morning by the way.

With the engine shut off, I have 12.3 volts on the battery, 0 on the D and F posts on the generator. With the tractor running about 2/3 throttle I have 14.3 at the battery, 17.3 on the D post on the generator, some trivial little .03 on the F post.

My Super 55 has a Delco, I used the same settings on the meter, and that one has a real working amp gauge. I had about 13v with the engine shut off on that one, but with the engine running, it was jumping all over between 18 something and 19 something. No jumping on the British one that I needed to check in the first place, so I'm guessing the British thing must be working better than the Delco? Not that it matters, just need a confidence boost before I try to take it on a drive Saturday.
 
12.3 volts on the over night battery is not exciting. 12.5 or 12.6 over night would be expected. Charging at 14.3 is perfect. I would monitor the battery state of charge periodically. Jim
 
I agree.. 12.3v means... either the battery is going bad or your have something drawing it down over nite... expect it to be 12.6 after 12 hours of rest. Or you have a bad volt meter.. You could charge it as before, but then disconnect the battery cable. let it sit over nite and if its at 12.6v,, you have something in the generator leaking it down. Are you turning off the run switch??
 
Sounds like it is charging correctly. If the battery goes dead again, you may have a draw. (Or a bad battery!) To check for a draw, disconnect the ground cable, and put the multimeter leads between the battery post and the disconnected cable end. If you have a voltage reading switch to the 10-amp scale, and see how many amps it draws-should of course, be none. Mark
 
Try using an old analog meter.
A generator is a smoother DCV
You mentioned Delco. If it's an alternator
you will sometimes have voltage jumping all over
using an electronic VOM.
 
I wouldn't think too much about the erratic readings, particularly if you're using a 20 dollar meter. Reliable digital (Fluke) meters tend to run 500 and up... and that's where you tend to get accurate readings.
12.6-12.7 should be your normal, full charge, resting voltage. Perhaps yours isn't quite fully charged yet.
If the voltage is truly that erratic on the alternator (accurate reading)... I'd say you have a regulator going bad. Try to get a good clean connection where you attach the leads...

Rod
 
(quoted from post at 02:31:51 07/08/22) Try using an old analog meter.
A generator is a smoother DCV
You mentioned Delco. [b:1e10390fc5]If it's an alternator
you will sometimes have voltage jumping all over
using an electronic VOM.[/b:1e10390fc5]


I've read that many times here.

I've worked as a mechanic in various shops, including running my own shop for 20 years, working on a wide variety of vehicles including tractors.

I've been using digital multimeters of various makes and quality in that time and the only time I've ever encountered that situation was if the meter's battery was weak or the leads were faulty.

The meter itself has never been at fault.



This post was edited by Carlmac 369 on 07/08/2022 at 04:52 am.
 

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