Do I need a new alternator?

[BDA]

I had some issues with charging in the past (I don't remember what the symptoms were) but I had my stock alternator rebuilt and things seemed to work pretty well. My ammeter would bounce around pretty much but the battery seemed to get charged. More recently, I had a problem with chewing up my alternator belt so I filed the mount on the bell housing to get a better alignment. Now, when I drive, the ammeter is pegged at +30 and the battery doesn't seem to get charged as occasionally, I'll have a dead battery. The belt is obviously tight enough since the ammeter is registering current. The plugs in the back of the alternator are securely plugged in. I'm not sure where else to look.

Any ideas?

[jbcollier]

If the ammeter is pegged at +30A, and is at 0 when off, then you know the alt is charging.  However, it doesn't look as though the alt output is being regulated.  Hook up a voltmeter across the battery and start the engine.  Rev it up to 2500 or so and see what the voltage is.  13.8v to 15.0v is just fine.  more than 15.2v will overcharge the battery and boil it dry.

[Gmg31]

Do you have an original alternate with separate regulator and relay? Check these first.

[BDA]

Thanks, John and Gmg31!

I'll check the voltage. The regulator is built in and I don't think they are available anymore.

I presume that using a smaller diameter cam pulley wouldn't help?

[blasterdad]

I would also try putting a battery in it that I know is good & see if it does the same thing, could be just a bad battery.
 

[4129R]

Are you sure the problem is not with the battery not holding its charge?

If the battery is stuffed, no amount of charging will make it hold its charge.

If you can, try borrowing another battery and see if the problem persists.

[4129R]

Snap !! Same comment, same time !!!

[jbcollier]

Myself, I prefer testing to replacing parts.  It takes mere seconds to hook up a voltmeter.  Right away you'll know something of your batteries condition and, shortly thereafter, the charging system as well.

[EuropaTC]

Hi BDA,

I'd go with the voltmeter test first, it's the most reliable pointer you've got and you'll know in seconds. 

If the regulator has gone then it could be boiling the battery so electrolyte level is a confirmation check ? Personally I'd not be happy driving with such a continual high charge rate, something sounds wrong there.

Spares back up for older Lucas alternators isn't (wasn't ?) too bad over here so you might be in luck.

Brian

[BDA]

Thanks guys for all the replies, guys!

The bettery is fairly new so I don't suspect it's not holding a charge. The alternator is a Delco and very similar to old units used on this side of the pond but the connections come out the back and the US version has them coming out the side so the proper regulator isn't available (I'm sure I would have called the usual suspects before the last time I tried to get a new regulator but I'll call again if that's the problem). In the meantime, I'll get some distilled water and top up the battery should it need it.

[BDA]

I haven't checked the voltage yet, but I just put a BUNCH (about 5 oz in each cell) of water in the battery. How long over charging the batter would you expect it to take to pretty much boil the battery dry?

[jbcollier]

5 oz per cell is a lot.  The battery may be compromised.  Fix the over-voltage issue first.  Then load test the battery.  Hopefully you're ok.

[Roger]

I had a bad regulator in a Delco alternator, a local repairer adapted a modern one to fit and it works perfectly. If that is your problem, I wouldn't give up on it but ask local shops. The one I found recognised a European-specification Delco the minute I walked into the shop with it, and I knew they were the right kind of people, they were rewiring a Model T Ford.

[BDA]

I originally had a guy who does a lot of aircraft avionics and electronics to rebuild my alternator. He said had to make some part and said he got a bit more out of it than it was supposed to give (sorry I don't know the details). It was ridiculously expensive and if I knew it was going to cost so much, I would have told him to forget it. At one point, I suspected the VR (this may not be in chronological order - it was several years ago!) and found one for the US version which has the connectors on the side rather than the back. For some reason, I didn't think I could adapt it.

Well, I found it this afternoon and it seemed straightforward enough (I don't know why I thought it was so difficult!) - just bend the lugs and add an extension! Simple. I'll check the voltage and if it's bad, I'll try my VR to see how it works. If I'm still SOL, then I'll go back to researching substitutions. There are several mentioned in the Yahoo group Knowledge Base.

[EuropaTC]

The battery may well be shot, all you can do is try it and see.  Fingers crossed you've caught it in time.

If you do end up chasing alternatives, a few years ago I fitted a Lucas 17ACR which fits (just) and is comparable output. The 16ACR would be better as it's a touch smaller. This year I changed it again when I found a neater solution, the Lucas A127.  Fitted to lots of UK cars and range from 55 amps upwards. Lots of info, wiring etc. on the web - some of the higher capacity ones would seem to need more wiring mods for our cars.  Chinese copies are available.....

http://www.martley.plus.com/lotusland2016/europa/16europa03.html

Scroll down and it's at the bottom under "2016 update"