I need an Alternator!!

[Jersey_Frank]

Hey folks! Frank here 🤙🏼

The family and I are first time RV owners and I’m in the market for an alternator. Here’s the specs I know:

CLASS A
1993 Monaco Dynasty (36’)
8.3L Cummins “pusher”
105,XXX miles

That’s about it. I’m mechanically inclined and understand basic engine function, but I’m quickly learning the ins and outs of electricity.

There’s a few local alternator and starter shops that could look at my current (dead) alternator, but would it be better for a refurb off the shelf?

I’m pretty positive my system is rated to a MAX of 200 Amps, so I shouldn’t exceed that… right? Lol

Any and all help would be greatly appreciated.

I’m located in Camarillo, CA and am willing to travel somewhat close to get this remedied.

R/
Frank

[Reka]

Get that one rebuilt then you will know for sure that you have the correct alternator for your unit. A refurbished one is just some else’s rebuilt unit

[code2e]

The alternator you are holding in the picture appears to be a rebuilt unit. The plate that is attached by 2 rivets has the original specs in it, before they painted it over. No chance there was a film on that plate, you could peel back removing the paint?

My first choice would be a custom rebuilder and have them test yours first. They should have a test bench for the purpose. Just in case you're dealing with a wiring issue outside the alternator.

If it needs repair, you would be better served by fixing yours than a random rebuild off the shelf. They would verify operation before you install.

[Jersey_Frank]

Awesome feedback I appreciate it! I plan on taking it to someone local for that purpose. Fingers crossed it’s in good condition!

[Jersey_Frank]

I’m pretty sure this one is aftermarket. Either way, I’m going to bring it in and get rebuilt. Thanks for the feedback!

[Argosy]

Unless you spent a lot of time cleaning that it's already been rebuilt. I've never seen one that old with over 100,000 miles look that good. Are you sure it's the problem? Before taking it in and say rebuild this I'd have it tested.

[Boogie_]

Just put an AC Delco w/internal voltage regulator in there and be done with it.

If you ever have a break down on the road just about any parts house will have one in stock.

[Argosy]

Originally Posted by Boogie_

Just put an AC Delco w/internal voltage regulator in there and be done with it.

Gas engine I'd agree with you. Diesel has a lot more space to work with and you should take advantage of how much heavier the bearings, windings, cooling, etc. are on those alternators. With the large battery banks it's a lot easier on a heavier duty alternator than one for a gas engine, despite similar power ratings.

[twinboat]

Originally Posted by Boogie_

Just put an AC Delco w/internal voltage regulator in there and be done with it.

If you ever have a break down on the road just about any parts house will have one in stock.

It won't work if the rig has a battery isolator. Very popular back then.

When they are installed, a chassis battery sense circuit is needed. If not, then the alternator will not charge at all or will run at full output and 18+ volts.

[Argosy]

Originally Posted by twinboat

It won't work if the rig has a battery isolator. Very popular back then.

When they are installed, a chassis battery sense circuit is needed. If not, then the alternator will not charge at all or will run at full output and 18+ volts.

I'm guessing you're talking about the diode isolators? Some of the later ones had 3 large terminals for alternator and battery attachment, and a smaller terminal for the sense wire. If not hook the sense wire between the isolator and battery. You can even hook it on the isolator battery terminal. That will also detect the voltage drop because of the diodes and adjust output correctly.

[RKins]

Originally Posted by Reka

Get that one rebuilt then you will know for sure that you have the correct alternator for your unit. A refurbished one is just some else’s rebuilt unit

I agree.
I tried for a month to get the alternator on my coach off, little access and every bolt snapped that I tried to loosen. Finally got it off and took it to a local (been here 50+ years) alternator shop that said that every bolt they touched snapped so they used a different carcass and rebuilt it to be a 160A alternator. They can make higher amp ones of course. It took minutes to install and cured my low voltage problem.

[153stars]

You can use higher amp alternator . 160-200 amp is pretty decent output unless your trying to run a lot off the inverter. A 260a wont hurt your batteries or coach. It could damage a lower amp diode isolator.

[Boogie_]

Originally Posted by Argosy

Gas engine I'd agree with you. Diesel has a lot more space to work with and you should take advantage of how much heavier the bearings, windings, cooling, etc. are on those alternators. With the large battery banks it's a lot easier on a heavier duty alternator than one for a gas engine, despite similar power ratings.

The alternator doesn't know what is making it spin.

If it bolts up and has adequate amps you're good.

There is nothing exotic or diesel specific about the alternator Frank is holding in the OP.

(edit: Because I have done it before)

[Argosy]

Originally Posted by Boogie_

If it bolts up and has adequate amps you're good.

There is nothing exotic or diesel specific about the alternator Frank is holding in the OP.

(edit: Because I have done it before)

There sorta is- size. Look at the hot and ground studs on the top of that alternator and tell me what automotive alternator you've see with studs that size. Diesel alternators often run the tach also, you lose that with an automotive alternator.

Generating electricity generates a lot of heat, that has to be dissipated. Converting an alternator to 200 amps does nothing to increase cooling, it increases the current capacity of windings and electronics. Bearing sizes aren't increased.

The alternators used on diesels are designed for higher output, larger case and fan for more air flow, heavier windings, larger bearings.

My point is if you have the room a diesel has the better solution is to use the alternator designed to produce 200 amps, not one running above design standards to produce 200 amps.