MEP802A 12V Generator

[loca5790]

Hey All,

I have a generator that had a fire and am looking to convert it to a 12v system. What all is needed? PN's and who has done it?

I'm missing alternator (some wiring's burned up), batteries, and alternator bracket. I can make the bracket no big deal

 

[98G]

Guages, switches, starter, internal wiring is all set up for 24V.

Why convert? 12V will use twice the amperage for the same energy...

 

[Light in the Dark]

The flywheel on the generator has teeth for a 24V starter only (the 12V Lister Petter/Onan starter will engage differently). Past that, you would need to convert everything in the DC system over. Not feasible or cost effective.

If the alternator is toast, you can leave it in place but unhooked (even if you need to take the regulator off or otherwise remove the defective innards, just to keep it in place as a belt tensioner) and start the unit with 24V (then just rig up a zip tie or similar to hold the fuel shutdown solenoid open (one of the drawing items while running, that will drain a battery).

 

[Digger556]

That's a big undertaking because the entire control system is 24V. It would be a total gut job and redesign of the controls.

 

[loca5790]

I don't have an alternator. The power draw of the unit is next to nothing. The alternator appears to be 63amp. I can easily build a buck boost/transformer circuit for a step up to run the rest of the system at 24V. I'd be surprised if the 24v starter is unable to start the system at 15ish volt.

 

[Ray70]

I think you'll be the first to attempt a 12V conversion. Don't know of anyone ever going that route.
Seems like a lot of effort for an unknown result and the risk or damaging more original components.
Why not just repair it back to original?
Doesn't sound like that big of a deal.
If you need an alternator bracket I probably have one.
I may also have wiring, depending on what is burnt.

 

[2Pbfeet]

I don't have an alternator. The power draw of the unit is next to nothing. The alternator appears to be 63amp. I can easily build a buck boost/transformer circuit for a step up to run the rest of the system at 24V. I'd be surprised if the 24v starter is unable to start the system at 15ish volt.

Actually, I would be quite surprised if the 24V alternator turns the engine over at 13V. That hasn't been my experience with other engines.

As @Light in the Dark pointed out above, the fuel solenoid is a not insignificant power draw.

If you want to put in a 12V alternator, and boost the output with a 12 to 24V boost circuit, that's doable in my book, but for the effort and reliability decrease, I wouldn't do a 12V + boost conversion. To me, the point of these units is that they are built for reliability. But that's me.

All the best,

2Pbfeet

 

[Scoobyshep]

Transformers in DC are more commonly known as electromagnets. So it's not as simple. Not to mention (because it's been mentioned above) all the controls would have to be redone.

 

[Light in the Dark]

I am sure if you can figure out exactly what's missing/deficient, folks here can get you squared away.

 

[loca5790]

I'm missing alternator and alternator bracket. I'm going to redo the fuel lines in an (or attempt to) I assume they are JIC 37* flare fittings. What's everyone doing for the feed line with the banjo bolt to the injectors? Making their own AN lines?

 

[98G]

Just a thought. Ditch the alternator entirely.

Put a 24V battery charger on the batteries, plugged into the house when not in use and plugged into the genset when in use.

 

[Ray70]

I'm missing alternator and alternator bracket. I'm going to redo the fuel lines in an (or attempt to) I assume they are JIC 37* flare fittings. What's everyone doing for the feed line with the banjo bolt to the injectors? Making their own AN lines?

Fuel lines at the pump and strainer are -4AN ( JIC-37*) If you need the hard line coming off the filter with the banjo fitting, I have that as well. if it's just your rubber lines going to the metering pumps that are leaking just cut the sleeves off and replace the hose with 1/4" rubber fuel line and clamps.
The alternators are available on occasion but getting pricey. I've gotten them on ebay before, but be sure to get one with a pulley as the pulley can be harder to find than the alternator.

 

[loca5790]

Just a thought. Ditch the alternator entirely.

Put a 24V battery charger on the batteries, plugged into the house when not in use and plugged into the genset when in use.

I've 100% thought about that...

 

[loca5790]

I am missing the back lid of the air cleaner as well. I got it to crank over but it won't fire.... fuel pump is working so. Will be digging into it more. Just trying to get it all the parts together as I go through it.

 

[flyfishtrailer]

I guarantee you that the folks here (really knowledgeable guys) can help steer you to getting the missing parts and getting it running again. Be patient, take and show lots of pictures and read the TM's before you ask questions. This is a great community, they just don't like doing all the work for you, rather help guide you through it when needed and enlighten you to discovery.

 

[Guyfang]

Start some "Parts Wanted" threads. That way you and who ever can help you are on the same sheet of music. As you get the parts in, we can close that thread and your thread on repair will not be 22 pages long. Pictures and descriptions go a long way to getting it right. If you haven't downloaded all the TM's in the TM forum, you should. Calling a part, a, "Thingamabob" can cause problems.

 

[Light in the Dark]

Just a thought. Ditch the alternator entirely.

Put a 24V battery charger on the batteries, plugged into the house when not in use and plugged into the genset when in use.

Yeah just need to find a belt tensioner that fits into the spot where the alt was, to retain the factory belt (or any belt, if you end up needing shorter). Thats why I have a dual bank onboard charger... it keeps the batteries topped when not in use, and if my alternator were to fail during run, I can just take an extension cord from the convenience outlet, and move it over to the plug for the onboard charger.

 

[Light in the Dark]

I am missing the back lid of the air cleaner as well. I got it to crank over but it won't fire.... fuel pump is working so. Will be digging into it more. Just trying to get it all the parts together as I go through it.

I've got that stuff, plus I am sure the rest of the guys here have the rest of the items you need. We will keep an eye out for your wanted thread when the time is right.

 

[DieselAddict]

If there is ANY question about whether the mechanical fuel rack is moving freely, have something close at hand that you can use to choke the engine intake off if it tries to run away. Not common these engines but it is possible. You don't want to take something simple and easy to fix like a sticking fuel injection pump and turning it into a rod sticking out of the block.

 

[Light in the Dark]

I've had (2) 802 run away on me... boy is that unpleasant.