TR2/3/3A Low charge with Alternator

[Meyer'sTR3]

My ride is a 1960 TR3 that has been converted over to 12 volt with alternator. I did not do the conversion. It seems that for some reason I am getting low voltage output or low amp output. I am not too sharp about these charging things. The problem raised its head only when I drove the car at night using the headlights. Next day I had a very low battery. If I don't use the headlights it seems to get by okay. I took it to a auto parts store so they could hook up their gizmo and check the amps/volts. They said I had a good battery, but the voltage regulator was putting out low volts. Being as the voltage reg is inside the alternator I decided to replace the alternator with a new one to cover both bases. Nothing changed. I am still getting a low amp reading on the dashboard amp gage. It goes well into the negative as soon as the lights are turned on. Even without the lights it does not show a positive. Is there something else I am not thinking of that would be giving me a low output?? The new Alternator was checked before sold to me and checked out okay.

 

[trrdster2000]

First off, a alternator is a good idea. If they are not wired correctly, not so good. Go to VTR.org and read how it's done and then check out what you have. Some of us did all the wiring behind the old regulator, but that's another story.
Sounds like they put it in and forgot to hook up a wire or two.

Wayne

 

[TR3driver]

If it is a one or two wire hookup, then any resistance at all in the output wire will cause similar symptoms. If the alternator itself checks out OK, I would look at adding the third wire, which allows the alternator to sense battery voltage separately instead of through the charging circuit. If you look at the diagram here https://vintagetriumphregister.org/alternator-overview/ I am talking about the wire labeled "Control Voltage Input (sensing)".

Also make sure that the output wire is big enough to handle the alternator's rating. The original yellow wire isn't big enough, especially for a one or two wire hookup. For a typical 60 amp alternator, you want at least 10 AWG and 8 AWG would be better.

Wayne, I couldn't find the article you are referring to. I remember there being a conversion article there, but can't find it now. Do you have a link?

 

[trrdster2000]

Randall, just walked in and like you, I remember the article but can't think right now where it was. I did it on a couple of TR4's and one is still around. If I can't find something in a day or two I will go take a picture of the back of his regulator. Very nice look and we added a fuse box with the large ground plate up front and the light wiring upgrade with relays. Nice car. Let's see what I find out.

Wayne

 

[trrdster2000]

https://www.britishcarforum.com/bcf...A-alternator-conversion-wiring-question/page2 Here you go!

Wayne

 

[Meyer'sTR3]

Thanks, this gives me some ideas to check out.