The Stovebolt Site Forums The Shop Area The Electrical Bay disadvantages of 12V generator

Are you aware of any disadvantage to using a generator rather than alternator for 12V conversion of an advance design truck? 12V = 12V regardless of the power source.

The generator should be fine for a bare bones truck. If you are running things like an A/C, high powered stereo system, powerseats/windows, you should get an alternator to match.

One disadvantage to a generator is that it doesn't charge at idle, only at rpms.

Not to be argumentative or anything, but My 6v Generator charges at idle. Granted, it charges MUCH better when running at higher RPMs...

One of the main reasons that someone would want to have a 12v Generator is to keep it looking original. The only people who would know any different would be people like us who can tell by looking at it what voltage it is.

If you don't care, go for the alternator, if for no other reason than for expandability's sake.

there is no real disadvantage for one or othere one big thing keep in mind is a 12v alternator output about 14.6v and a 12 dc generator output is 12v at X RPMS you would whant a generator that has an output os about 13V at your idle but will not exseed much more then 17V at any rpms that you will mantane for a long peread of time (keep inmand that it is the rpms of the pully not your engine)

The one big advantage to an alternator over a generator is the amperage output. Most generators only run 25 to mayby 50 amps depending on the regulator. An altenator can easily produce over 200 amps if it is set with the correct internals. However an alternator will not recharge a dead battery like a generator can because they require a minimum
amuont of voltage to start producing current flow.

Thanks for your replies. I was digging to see if anyone would mention radio noise or premature HEI failures.

The advantage of a generator to me is partially the look, but direct bolt-on with no special bracket or harness requirements are a factor.

50GMC253, I found something you may be interested in. Powermasster has an alternator that looks like a stock GM generator. Their adress is www.powermastermotorsports.com. Look in the powergen section. You may have to contact them directly for priceing, I did not see any on the site.

You better not run a charging system up to 17 volts. You will not have any lights,radio, or gauges left. Where can I find a 200 amp. alt.?

J.C. Whitney has them, also try www.motorcityreman.com. Whitney also has the Powergen, they are $399.99, a lot higher than I expected them to be.

For a 200 amp alternator (Delco 22si or CS130) I'd see if it came stock in something and pull it at a u-pull it style junk yard where they charge a flat $25 for an alternator and will refund your money if it doesn't work. You might have to change the serpentine pulley to a 3/8" v-belt, but that is easy. The thing to look for is the mounts and plug location-

For example, SOME of the cars/trucks the 200 amp alternators were stock in are 91-96 impala/caprice with big v-8s and:

(1987) Chevrolet Blazer, GMC Jimmy 5.0L, 5.7L
(1987-93) Chevrolet, GMC P Series Step Van 4.3L, 5.7L
(1987) Chevrolet, GMC R, V Series Pickup 5.0L, 5.7L
(1987-88) Chevrolet, GMC Suburban 5.0L, 5.7L
1994-1997) Chevrolet S10 Pickups with 2.2 liter engine(1994-1997) GMC Sonoma with 2.2 liter engine
(1996-1997) Isuzu Hombre with 2.2 liter engine
(1989-88) Buick Century 2.8L
(1988-87) Cadillac Cimarron 2.8L
(1989-87) Chevrolet Beretta, Cavalier, Celebrity, Corsica 2.8L
(1994-90) Chevrolet Beretta, Cavalier, Celebrity, Corsica 3.1L
(1993-90) Chevrolet Lumina APV Van 3.1L
(1989-87) Oldsmobile Ciera, Firenza 2.8L
(1993-90) Oldsmobile Silhouette 3.1L
(1989-88) Pontiac 6000 2.8L
(1994-90) Pontiac Sunbird, Trans Sport 3.1L

Chevy Avalanche (2002-2004) with 5.3, 8.1 liter engines
Chevy Astro Van (1996-1999) with 4.3 liter V6 engine
Chevy S-10 Blazer (1996-1997) with 4.3 liter V6 engine
Chevy C Series Pickup (1996-2000) with 4.3, 5.0, 5.7, 6.5, 7.4 liter engines
Chevy K Series Pickup (1996-2000) with 4.3, 5.0, 5.7, 6.5, 7.4 liter engines
Chevy Express Van (1996-2004) with 4.3, 5.0, 5.7, 6.0, 6.5, 7.4 liter engines
Chevy Silverado Pickup (2000-2004) with 4.3, 5.0, 5.7, 6.0, 6.5, 6.6, 7.4 , 8.1 liter engines
Chevy Suburban (1996-2000) with 4.3, 5.0, 5.7, 6.5, 7.4 liter engines
Chevy Suburban (2000-2004) with 5.3, 6.0, 8.1 liter engines
Chevy Tahoe (1996-2000) with 5.7 gas engine, 395 diesel engine
Chevy Tahoe (2000-2004) with 4.8, 5.3 liter engines
GMC Jimmy (1996-2000) with 4.3 V6 engine
GMC Safari Van (1996-2000) with 4.3 V6 engine
GMC Savana Van (1996-2000) with 4.3, 5.0, 5.7, 6.5, 7.4 liter engines
Chevy Savana Van (2003-2004) with 4.3, 4.8, 5.3, 6.0 liter engines
GMC Sierra Pickup (2000-2005) with 4.3, 4.8, 5.0, 5.7, 6.0, 6.5, 6.6, 7.4 , 8.1 liter engines
GMC Sonoma (1996-2000) with 4.3 V6 engine
GMC Yukon (1996-2000) with 4.3, 5.0, 5.7, 6.5, 7.4 liter engines
GMC Yukon Denali (1996-2000) with 4.3, 5.0, 5.7, 6.5, 7.4 liter engines
GMC Yukon (2000-2004) with 4.8, 5.3 liter engines
GMC Yukon Denali (2001-2004) with 6.0 liter engine
GMC Yukon XL (2000-2004) with 5.3, 6.0, 8.1 liter engines
Isuzu Hombre (1997) with 4.3 V6 engine
Isuzu Ascender (2003-2004 ) with 5.3 liter engine
Olds Bravada (1996-2000) with 4.3 V6 engine
Cadillac Escalade (2002-2004) with 5.3, 6.0 liter engines

To name a few...


Another possibility is e-bay, type in 200 amp alternator and you'll find tons for $125 and up.

Wrenchbender-- in reality your alt. is puting out an avrige of 16.7v wen you are at a cruse but wen you are at a higher rpm it will put out upto 20v

16.7-20v? Is this common? This is not an disagreement or a start of an argument; just an honest question.

Most 12v auto batteries seem to have a lower recommended charging voltage (13.8-14.4v seems to be common) and a maximum charging voltage (12v Optima batteries have a 15-15.5v maximum voltage and a warning that even at this voltage the electrolyte will boil/evaporate, the relief valve will open, and battery life will be reduced).

from Optima "When used with a properly regulated constant voltage charging system (such as an alternator), the OPTIMA battery will normally not produce hydrogen gas. Occasional gassing can occur when charging at higher voltage levels or in extreme high temperature conditions. In automotive applications this typically will not happen if the alternator/regulator stays below 15 volts."

I'm with Tim - I've never seen any alternator spec'd at more than 15V and would need to see some mfg info explaining the 17-20V - also that's part of what the voltage regulator is for, internal or external, to prevent blowing up the battery

also note that turning an alternator takes about 1hp for each 25amps it can produce - if you can do fine with an 80 amp unit, why sacrifice as much as 5hp on a 200 amp? unless you want to have a portable welder along for the ride

Bill

I doubt that a 200 amp alternator providing 80 amps pulls much more power from the engine than an 80 amp alternator providing 80 amps, maybe even less due to the fact that it would be running much cooler.

There are alternators rated at 16-18 volts, but they are used for late model diert track cars. They use the higher voltage to get a hotter spark for higher horsepower. They also have to run either a 16 volt or a special 16-12 volt dual post battery to run that alternator.
I agree with red58, unless you have a high load requirement (welder/winch/over-powered stereo) you don't need more than 80 amps.

An unregulated alt. or gen. will run up very high voltages but are regulated for practical auto use. Any thing over 14.5 volts will shorten bat life & damage components. A gen. will distruck itself if run very long over it,s rated output.