MEP-803A Alternator Issues?

[TheAlfredo]

So I recently purchased a 803a and had it delivered to panama City, Florida after the hurricane. I was told the genset didn't have batteries, so I purchase 2 new ones. Hooked them up, genset started right up. Later that day I was told the genset would not restart. Went to look at it and the battery/ies were dead. We jump started and it worked great. I checked the FU-1 and it was fine. We swapped out the batteries with 2 older ones off another working genset and started right up.

Next day same thing happened, so we decided to get two battery chargers and leave them plugged into each battery and plugged into the convenience receptacle. That got my cousin's through until they got utility power back several weeks later.

Now I have the genset back in Miami. Today I went to start it, and as expected, it wouldn't start. Took out my multimeter and checked at the slave receptacle and got around 12v. So I checked each battery individually. One was dead and one was charged. I put a jump pack an the dead one and the genset started right up. Turned off the jump pack and disconnected it...genset continued to run.

Went to run a load on the genset using a load bank, and wasn't getting any power at the lugs...even though I had 120 at the convenience Receptacle. K-1 didn't appear to be closing. I'm guessing because it doesn't have the 24volts to close?

While running I checked voltage at the Slave Receptacle and it was NOT over 24volts. (can't remember right now...but it was I think 17volts.) I used the meter on the back of the alternator and got the same reading. I'm guessing the alternator is bad?

But what has me puzzled is that one battery was drained but the other wasn't. I'm charging the batteries overnight and tomorrow I plan on trouble shooting again. Any Pointers would be appreciated.

 

[rhurey]

1) What's the charging meter showing when the set is running? Should be showing charging when the set is first started, then taper down to 0, but always a bit positive.

2) Physic debugging: Bad alternator diodes. Just because that's what failed on mine. Easy rebuild if that's it.

 

[kloppk]

Also check for chaffed battery cables. One battery being drained could be caused by one of the cables shorting to ground.

 

[Coffey1]

The regulator on the alternator is probably the problem.

 

[Guyfang]

Can you jump the set off using the slave receptacle? If so, disconnect the battery's. Tape off the leads, or isolate them. Jump off the set. Remove the jumper cable. Will the set contine to run? If so, measure the output of the alternator. Should be about 27 volts.

But if the set stops running as soon ar the slave cable is removed, the alternator is bad. Or if the output is low, the maybe the regulator is bad.

Any time you put charged battery's in and they are dead in the morning, it points to the alternator. And if you do it more then twice, you are wasting time. It sounds like diodes to me.

 

[dav5]

Look up Prestolite Leece Neville 24V alternator on Ebay. There is one there for around $68 that is brand new. The NSN is in one of the photos. Check it before ordering. The one I got for a spare is identical to the OEM alternator on my 803A. See Green Mountain for an explanation of the differences between 8MR3005c and 8MR3005ca alternators.

 

[TheAlfredo]

Thank you

Can you jump the set off using the slave receptacle? If so, disconnect the battery's. Tape off the leads, or isolate them. Jump off the set. Remove the jumper cable. Will the set contine to run? If so, measure the output of the alternator. Should be about 27 volts.

But if the set stops running as soon ar the slave cable is removed, the alternator is bad. Or if the output is low, the maybe the regulator is bad.

Any time you put charged battery's in and they are dead in the morning, it points to the alternator. And if you do it more then twice, you are wasting time. It sounds like diodes to me.

The generator shuts off immediately when the Slave cable is removed.

 

[Guyfang]

No out put from the alternator.

 

[Bmxenbrett]

Yes you need to check the alternator output. You didnt do this in any of the previous tests...but you did run the set with battery chargers charging the batterys. Thats a bad charging circuit almost every time. At this point your lucky if you only have one dead battery.

I believe you need proper 24+v to close relays and contactors in the set. This is prob why your not getting power 120/240v

 

[csheath]

Kudos for the creative approach using two chargers on the convience recepticle. Way to get by in a pinch!

 

[Farmitall]

Kudos for the creative approach using two chargers on the convience recepticle. Way to get by in a pinch!

It is a great idea......provided that you can get the unit running in the first place.