One wire alt. Question

[JUNKYARDJOHN]

I've been doing alot of studying about the cucv electrical system here lately, & have a question for some of you, more electrically inclined individuals than me. (I don't know much about electrical systems & I can prove it) I've been restoring & hotrodding chevy trucks for quite a few years now, & I've always replaced my alternators (when I needed to) by having them rebuilt as one wire alternators. It always seemed to make my electrical systems simpler & cleaner. Do any of you electrical gurus have any reason why this shouldn't be done on these cucvs?? All of these old alternators are going to need rebuilding ,sooner or later & it won't hardly cost anymore. It seems like a simple enough upgrade & after all.. they are just 100 amp, 12 volt alternators.(only one wire going directly to the battery) I realize the right (pass side) alt will need an extra isolated ground wire, but is this a good idea or not.... & why?? Please excuse my ignorance on this subject & enlighten me. THANKS IN ADVANCE... John

 

[jdemaris]

I've always replaced my alternators (when I needed to) by having them rebuilt as one wire alternators. It always seemed to make my electrical systems simpler & cleaner. Do any of y
ou electrical gurus have any reason why this shouldn't be done on these cucvs??

The purpose of the standard three-wire hookup to the Delco 12SI alternators is so actual battery voltage can be sensed AT the batteries. A one-wire regulator does not to this and senses voltage AT the alternator instead. That isn't a big deal when batteries are very close. Also, the one-wire regulator takes more RPM to self-excite and start charging.

So I guess the answer your question is, yeah it will work. Not quite as good as the OEM hookup, but good enough. Main shortcomings to the one-wire self-excite regulator stuck into a Delco 10SI or 12SI are . . . lack of exact battery charge voltage being sensed, high RPMs needed for alternator to first start charging, and difficulty in hooking in a charge-indicator "idiot light."

 

[gaunt1969]

You can do it on alt 1 only, Alt2 has to have an isolated ground. No way around it other than to convert to a 12volt system. And then you just get all sorts of cold starting problems and other stuff. And what would a cucv be without a 24v system . A "CIVI".

 

[BIG_RED]

if you get your #2 alternator rebuilt... MAKE SURE IT IS REBUILT WITH AN ISOLATED GROUND!! (there should be no continuity between the Negative output post and the metal frame). Failure to do this could cost you a battery, an alternator, a bunch of wires.. maybe your life if you're really unfortunate and a battery blows up in your face.

I don't mean to talk down to you, I'm just going on what you said about you not knowing too much about alternators. I'd like to save you the $$$ and trouble. Good luck!

 

[JUNKYARDJOHN]

if you get your #2 alternator rebuilt... MAKE SURE IT IS REBUILT WITH AN ISOLATED GROUND!! (there should be no continuity between the Negative output post and the metal frame). Failure to do this could cost you a battery, an alternator, a bunch of wires.. maybe your life if you're really unfortunate and a battery blows up in your face.
I don't mean to talk down to you, I'm just going on what you said about you not knowing too much about alternators. I'd like to save you the $$$ and trouble. Good luck!

THANKS... like I said in the original post... I realize the # 2 alternator needs to be an isolated ground, so I guess it wont technically be a one wire alt. but thanks for the heads up. This is after all the first 24 volt setup I've messed with, but with all the helpful electrical gurus on this board, I feel pretty confident. I'm not a TOTALLY, HELPLESS PUKE that needs advice on airing up a tire or changing my own oil. but thanks just the same. John

 

[BIG_RED]

One wire vs. 3 wire alternators is quite a topic of debate for all kinds of vehicle modifiers. I would stick with a 3 wire unit. The dash light that tells you your batts are not charging has saved me before. (my exterior lights were all bright, there was no indication other than the dash light that something was up until I checked with a meter and got less than 13 volts with the engine running). Had I left without seeing the light, my front battery would have died on the highway in a blizzard, stopping my engine, leaving me stranded. (I had tools in the truck, so I probably would've been ok, but I would've froze my hands off getting it going again). I also run a lot of high-current electrical stuff off my truck (inverters, extra lighting, etc). If you are going to need lots of amps - 3 wires will keep your voltage more consistent. (if your voltage drops too much, your electronics overheat/burn-up).

Just my opinion(s), good luck.

 

[JUNKYARDJOHN]

One wire vs. 3 wire alternators is quite a topic of debate for all kinds of vehicle modifiers. I would stick with a 3 wire unit. The dash light that tells you your batts are not charging has saved me before. (my exterior lights were all bright, there was no indication other than the dash light that something was up until I checked with a meter and got less than 13 volts with the engine running). Had I left without seeing the light, my front battery would have died on the highway in a blizzard, stopping my engine, leaving me stranded. (I had tools in the truck, so I probably would've been ok, but I would've froze my hands off getting it going again). I also run a lot of high-current electrical stuff off my truck (inverters, extra lighting, etc). If you are going to need lots of amps - 3 wires will keep your voltage more consistent. (if your voltage drops too much, your electronics overheat/burn-up).
Just my opinion(s), good luck.

I have been contimplating installing two (good) 12 volt-meters in the cab. one to each alternator & maybe one more for my incab electrical 12 voit system. I never was one for basically a dummy light. something about that good-bad-red-green gage that doesn't blow my skirt up. ANY THOUGHTS?? I've always been one to moniter my engines vitals. John