Altenator amps?

thisoldhippy · August 17, 2012, 07:42 PM

OK! Being the one putting the Isuzu diesel in my winny! I have come across a problem wondering about everyone's input! The diesel has an alternator with a vaccum pump on the back! I need the vacuum pump for the brakes! However it is only an 80A unit! Was wondering what you think about that! The one on my 440 is a truck style that I had worked on it puts out 125 amps now! Diesel guys are saying to build mounts and run them both. The 80a for the engine and that part! Then wire the 125a one for the coach batteries! Thanks Gary

gadgetman · August 17, 2012, 11:32 PM

I dont think I would worry about only having 80 amps, the money spent on a second alt you could likely install hundreds of watts of solar

ClydesdaleKevin · August 18, 2012, 06:35 AM

Since you already have the secondary alternator on hand, I'd say go ahead and fabricate the mounts for it and use it. Ya can't have too many amps in an RV, although you might have to get creative with where you mount it, and how you wire it in.

Kev

thisoldhippy · August 18, 2012, 09:51 AM

That is where I am at with it! Not much expense just sweat! I will eventually be doing solar as well! Final plan is to isolate the chassis from the coach! Putting an optima in the engine bay. Then 6 golf cart batteries in the battery box for the coach! Do need some help as to which book I need from here to figure out the wiring though! Thanks Gary

Froggy1936 · August 18, 2012, 08:42 PM

Why not the big alternator and an elecrtic vacuume pump with a storage tank Frank

thisoldhippy · August 18, 2012, 09:11 PM

Haven't looked that direction yet!

ibdilbert01 · August 19, 2012, 12:19 AM

Quote The 80a for the engine and that part! Then wire the 125a one for the coach batteries! Thanks Gary

Thats exactly what I would do! I currently run the stock alternator for the engine, and I have a 2nd heavy duty one I run for the coach. I figure I'm never stressing my engine alternator out, and if it were to die on a trip, I could always run on the 2nd alternator.

Oz · August 19, 2012, 06:25 PM

Definitely take in Tim's advice. In just a weekend he, and I quote, "just threw together" a whole wiring sytem of phenomenal gadgetry and electronic wizardry (I think those are the correct, technical terms). Currently, he's been a little busy. In addition to providing professional evaluations of all types of carnival foods, he's building a linear accelerator... He'll have the first atomic powered Winnebago in history...

thisoldhippy · August 19, 2012, 07:57 PM

Yes that is the direction I plan on going! Mark which of the manuals you have on here will help me the most with the wiring?

Oz · August 19, 2012, 09:16 PM

We have the chassis wiring diagrams for 1979 M300 through M600 in the Memer Area, Manuals, Diagrams & Info. Accessible for Full Members. $5 gets you Full Membership and access to it an a lot more. That section alone has excellent, downloadable info in addition to wiring diagrams.

thisoldhippy · August 19, 2012, 09:51 PM

EXCELLENT!!!!

audioguyinMI · August 20, 2012, 12:56 AM

Since you're asking for two cents, I will include mine:

80 amps is sufficient to handle anything you might need. If these rigs were start and stop I might have a different opinion, but when we get in them we usually drive hundreds of miles - plenty of time for the largest array of batteries to be charged.

Taking a system that is simple and making it complex is asking for trouble. If redundant alternators offered a real advantage they would have been introduced from the manufacturer a LONG time ago.

My vote would be to install whichever alternator is easy to find at a parts store, and make the system work with that one. External vacuum is not hard to create. Isolating the chassis electrical from the coach electrical could be opening a can of worms... and having selectable interconnectivity (which mine does from the factory) can be a real advantage in the case of a weak battery.

Best of luck to you.

Bill

ClydesdaleKevin · August 20, 2012, 06:29 AM

A lot of coaches, even older ones, came standard with dual alternators, so they were on occasion factory additions.

Kev

DaveVA78Chieftain · August 20, 2012, 06:55 PM

First thing to remember is in the 70's and 80's the stock charging system was primarily designed for the chassis system, not so much the chassis and coach. The 60-80 amp alternators support chassis battery, headlights, and normal running lights fairly well with out stressing the alternator.

We like to "add" stuff and "change" things so you have to think about what your actual loads on the system are. If, it is mostly stock without big stereo systems, computers, TV's, dorm fridge, etc., then the stock system will work fine. It's those extras that govern whether you need something bigger or more. It comes down to how much amperage are you pulling from the alternator for extended periods of time. The more amps you pull, the harder it works, the more heat generated which is the real enemy of an alternator. The bigger battery bank you have, the longer it takes to recharge it therefore the more stress on the alternator.

Each charging setup has to be planned based on what loads it is expected to normally handle. If you do not do that, then you may be replacing alternators more often than you want to.

Dave