Alternator saga

[Corax]

Wondering if anyone can help me out here:

- 18 months ago during routine maintenance my mechanic suggested I switch out my alternator as it was not charging properly and would probably fail soon. So we replaced it with a new one from Max Overdrive.
- Drove from Banff to Revelstoke soon after (300 km) and the van would not start the next day. Took it to a mechanic in Revelstoke and the alternator was not working. My mechanic in Banff grabbed my old one, had it rebuilt, sent it to Revy and the shop there put it back in. (Sent the other one back to Max Overdrive for a refund).
- All was well, everything worked although a short while later I noticed that occasionally the headlights would brighten and dim when I revved the engine. At the time I thought "alternator" but wouldn't believe it because we had just replaced it.
- 3 weeks ago, driving at highway speed in a hard rainstorm, the vehicle just quit. I coasted to the shoulder, restarted no problem, and continued on my way. This has never happened before.
- 2 weeks ago (over a year after we replaced the alternator) I noticed a slight rotten egg smell. Couldn't figure out what was up even after I inspected the engine and undercarriage. Then the radio display started acting weird (showed an error message). Then the fan quit when I turned the A/C on. I checked the fuse box, a fuse was blown, replaced it, everything worked, continued on my way.
- The rotten egg smell got worse. After about 100 km I had a look at the engine again and now the battery (2 years old) was venting vapour. Limped it into Revelstoke, mechanic said faulty battery, replaced it, sent me on my way.
- 150 km later (Golden) the smell and venting battery were back. Limped home to Banff. The new battery is shot and now my mechanic here says the alternator needs a rebuild again - it was overcharging the battery.

Is something fishy here? I can see why a 16 year old alternator would need replacing, but why did the Max Overdrive alternator not work properly and why did the rebuilt alternator fail after 18 months? What are some possible causes for early alternator failure in the Deli?

Thanks.

[Green1]

sounds to me like the voltage regulator... I'm not sure, but on most vehicles this part is attached to or part of the alternator, is it possible that despite the new alternators you were still using the same voltage regulator?

[Corax]

I've been thinking the same thing - I think the voltage regulator is part of the alternator in this case but it may not have been replaced during the rebuild for some reason. The alternator is at the same rebuild shop right now so hopefully I'll have a better idea what is going on with it and what happened last time round when they pull it apart next week.

[Corax]

Problem solved - there was a short that caused the battery to get overcharged and blew the alternator at the same time. Fix the wire, rebuild the alternator, a new battery and we're good to go.