MEP-804B - New to me, I have a few questions

[410Customs]

Thanks fellas

Unfortunately for me it is one step forward and two steps back with this thing.
The new alternator is in! AND

Drum roll please..........................

NOT WORKING!
So yeah seriously now we have a new issue.
The new alternator installed is a 24V, 40 AMP unit
Installed just fine, wired up same as the old one, bolted right up, belt is tight

NATCAD I love this topic!! We are in the market for some new panels and a 3rd inverter...etc but that will have to wait until I can sort this charging issue out

As soon as I start the generator the ammeter pegs past +20 and in a few seconds the 25 amp circuit breaker pops and the unit quits charging
So I tried moving the ground wire, same thing
I get my multimeter out and check battery voltage
Before the circuit breaker blows the battery voltage was climbing....23.5, 24, 25....when it gets to 25.5 the circuit breaker pops and the alternator quits charging.

WHAT THE HECK IS GOING ON WITH THIS THING????????
The system should charge at 25-27 volts.
This is a new alternator tested before I installed it

So now I'm guessing we can see why the old Hitachi unit was failed, something is fishy

Lucky for me the battery charger I ordered on Amazon came and I was using that yesterday to recharge the batteries.
This is a Norco 2600 24V battery charger, I plug it in to the courtesy outlets and set it on 24V, hooked up to the battery bank...it was charging them just fine

So now I am thinking, well maybe I cannot use glass matt batteries in this unit? So I did some research
Nope........ the Optima red tops it came with were glass matt and they were approved for use in this unit
Are the batteries I installed too large? Drawing too many amps? I do not see how that is possible, they are just Everstart 12V group 65 AGM batteries
The gauge pegs way past +20 amps.........
IO have checked the battery wiring and alternator wiring 100 times, I know it is hooked up correctly

So do I have a bad circuit breaker (not likely)
what causes an ammeter to PEG? (too many amps right?)
Why would it be pulling too many amps enough to blow the CB every time?

New unit

Now I am starting to see why I got such a good deal on this thing

Any ideas on where to start?
New shunt? New circuit breaker? I am not a big fan on throwing parts at a machine, I would rather know what the heck to test!!

NOT GOOD!!!!!!

Our ducks:

our elk herd

 

[loosegravel]

Thanks fellas

NATCAD I love this topic!! We are in the market for some new panels and a 3rd inverter...etc but that will have to wait unfortunately until I can sort this charging issue out

Unfortunately for me it is one step forward and two steps back with this thing.
The new alternator is in! AND

Drum roll please..........................

NOT WORKING!
So yeah seriously now we have a new issue.
The new alternator installed is a 24V, 40 AMP unit
Installed just fine, wired up same as the old one, bolted right up, belt is tight

As soon as I start the generator the ammeter pegs past +20 and in a few seconds the 25 amp circuit breaker pops and the unit quits charging
So I tried moving the ground wire, same thing
I get my multimeter out and check battery voltage
Before the circuit breaker blows the battery voltage was climbing....23.5, 24, 25....when it gets to 25.5 the circuit breaker pops and the alternator quits charging.

WHAT THE HECK IS GOING ON WITH THIS THING????????
The system should charge at 25-27 volts.
This is a new alternator tested before I installed it

So now I'm guessing we can see why the old Hitachi unit was failed, something is fishy

Lucky for me the battery charger I ordered on Amazon came and I was using that yesterday to recharge the batteries.
This is a Norco 2600 24V battery charger, I plug it in to the courtesy outlets and set it on 24V, hooked up to the battery bank...it was charging them just fine

So now I am thinking, well maybe I cannot use glass matt batteries in this unit? So I did some research
Nope........ the Optima red tops it came with were glass matt and they were approved for use in this unit
Are the batteries I installed too large? Drawing too many amps? I do not see how that is possible, they are just Everstart 12V group 65 AGM batteries
The gauge pegs way past +20 amps.........
IO have checked the battery wiring and alternator wiring 100 times, I know it is hooked up correctly

So do I have a bad circuit breaker (not likely)
what causes an ammeter to PEG? (too many amps right?)
Why would it be pulling too many amps enough to blow the CB every time?

New unit

Now I am starting to see why I got such a good deal on this thing

Any ideas on where to start?
New shunt? New circuit breaker? I am not a big fan on throwing parts at a machine, I would rather know what the heck to test!!

NOT GOOD!!!!!!

Our ducks:

our elk herd

Depending on what batteries you’re using and the state of charge that they have you may be asking too much from your alternator. Try charging your batteries before starting the machine. It is a common misconception that alternators are battery chargers. They are not. When we try to charge batteries with alternators bad things can and do happen. They’re designed to replenish the power used to start the engine and to maintain a specific system voltage once the machine is running. If you are using over-sized batteries and the state of charge on them is low (like it sounds that it is) it is very possible that it is actually exceeding the 25 amp circuit breakers capacity. Start with fully charged, correctly sized batteries.

 

[410Customs]

VERY GOOD ADVICE

Thank you
I will charge them to 100% with my new charger and then try again
I am SURE that is it
I believe you are probably correct!!

batteries were at 22.5V when I installed the new alternator, well below 24V basically they were below 25% capacity and yes my dumbass expected the alternator to charge them up hahahaha

I feel good about this
I am looking forward to being able to move on and get back to the fun stuff like adding another inverter/charger on the 3rd leg

 

[NATCAD]

looking forward to hearing if that fixed the problem

 

[loosegravel]

looking forward to hearing if that fixed the problem

I work as a mechanic for the transit company in Seattle. Been there for 25 years now. We often have buses with dead batteries in the yard, mainly from sitting so long waiting for parts. But that's a whole other problem! I always cringe when I see other techs who will routinely jump start these buses and then put them back in service without replacing the batteries, or properly charging them. We have (4) group 31 Odyssey AGM batteries in each bus. That is one heck of a lot of resistance on the charging system when these batteries are low on state of charge. The only "proper" way to treat these buses is to remove the low state of charge batteries and put them on the charging rack. Then install other, fully charged or new batteries. Instead what we get are trouble calls because the buses won't start after a lay-over. In other cases we get calls because "the bus smells like rotten eggs." This would be from the AGM batteries heating up and steaming out of the vents. And the worst case scenario is an unplanned thermal event, which we have had a few. I'll let you use your imagination on what this might look like. Good luck to you on your generator. I'm almost positive that you've got this problem licked!

 

[Guyfang]

New shunt? (Think about what a shunt is. It is more or less a fuseable link, and it is a way to reduce the amount of amperage in your Batter Charging System, AT the M4 METER. What you just do not want to do, and its cost me two wrenches and a big fat scream of F**K , when I managed to run afoul of the posts on the back of the Battery charging meter. So if you look at the MT4, (shunt) you will see, it works, or NOTHING works. Main power into the control cube is to the MT4. If its broke, meaning burnt through, nothing works. Thats the only failure MT4 can have.) New circuit breaker? (Did you look at the CB? See what its rated for? It might be doing its job, or someone may have put a smaller one in) I am not a big fan on throwing parts at a machine, I would rather know what the heck to test!!

 

[410Customs]

804b is purring like a kitten the batteries are at 75% I will shut off when they reach 100% and tomorrow we will reset the CB and try this again!
The charger says 7.8 hours to fully recover 24V AGM been running about 5 now.........
Big learning curve on these things
Thanks dudes

 

[410Customs]

all right well it took 3 days to get the generator run time needed to bring the batteries up to 100%
The generator charges our battery bank in just a few hours and the sun has been out (we have also had snow and rain!)
so not much generator time needed lately.
Last night when I shut the 804b down I saw that the two glass matts are finally at 100%!
So tonight we shall try to close the circuit breaker and see that the new alternator and charging system are indeed working
fingers crossed.

Been looking at batteries and solar panels............ please send $$$

 

[NATCAD]

how did it go sir...? those panels will pay for themself in diesel pretty quick.

 

[410Customs]

Allright you guys I finally had a chance to run the generator with the batteries fully charged
This time of year we have plenty of sunshine we hardly need to use this thing at all 7 months of the year

at first I was concerned because once again the ammeter pegged past 20+ amps and the circuit breaker blew
I let the 804b warm up and tried again
The ammeter went to 20+ but this time it began to drop... almost as if the system finally reset?
it seems to be a solid state setup with a shunt and ammeter, in any case, it looked like it was finally going to work.
Two hours later and indeed it is working! Finally a full hooked up a properly working gen set

Now I can focus on how to utilize that third leg!!
Thanks again all the advice and information is really appreciated
Very happy with this genset, I know we are only using 2/3 of its ability right now but even at 15/20% load it seems to just sip the red diesel, a huge upgrade vs the propane guzzler we had before
The 804b also had a little rattle can touch up, I have a selection of camo krylon paint and I wanted to remove all the bright tags the surplus machine had. I think it came out pretty well.
This summer we will be building a generator house

 

[NATCAD]

looks good!
can anyone comment on what orifices might need plugged to prevent mice to get into generator box? does the 804a have holes on the bottom that need plugged like the 803a?

 

[410Customs]

I have not had any mice in the 804b as far as I can tell
I did do the first oil change!
6 quarts of Mobil delvac 15W-40 and a Carquest filter at 247 hours now
Genset runs awesome!! Like flawless every time..... the alternator is charging the two glass matts perfectly

plans are in the works to add another battery bank to our house with another inverter, this will run off the third leg of the 804b
However thus far there are no ill effects to running at 208V off two legs........... she sips red diesel, I'm in love!!

 

[Coug]

I have not had any mice in the 804b as far as I can tell
I did do the first oil change!
6 quarts of Mobil delvac 15W-40 and a Carquest filter at 247 hours now
Genset runs awesome!! Like flawless every time..... the alternator is charging the two glass matts perfectly

plans are in the works to add another battery bank to our house with another inverter, this will run off the third leg of the 804b
However thus far there are no ill effects to running at 208V off two legs........... she sips red diesel, I'm in love!!

I know the feeling. While I don't run my 802 like you do your 804, I do love having it around.

 

[410Customs]

allright guys here we are, 804b has been working perfectly all spring summer and fall
We are at about 500 hours now on the meter, oil has been changed a few times, all is well
She runs at about 40% of the rated load because we are still using two of the three "legs"
However that is about to change.
I have upgraded our house battery bank, we are now running on 16ea Renogy 200ah 12V AGM batteries. 48V, 800ah, battery bank is working awesome.
The old batteries (2 year old Lithium ion) are being setup as a second battery bank using their own inverter on a 24V system.
So I am getting ready to run the third leg of the genset to its own inverter!!
Also in the works is a generator cover, some sort of roof to protect this thing all winter.
Also getting ready to order a MEP-804B remote generator start setup!
stay tuned

 

[410Customs]

Allright we are up and running with all 3 phases hooked up!
We now have three 120V power inverters charging battery banks
To accomplish this we pulled a single 6ga wire through the existing conduit from genset to house, then we ran the same 6ga wire through the shop and over to our "new" 24V battery bank. So now line 3 is powered!!! All 3 phases.

So now the big house and shop are powered by a 48V AGM 800 amp hour battery bank and the cabin and addition are powered by a lithium ion 24V 400 ah battery bank
There are two outback inverters (line 1 & 2) on the 48V bank and a new single Sungoldpower (Renogy) inverter (line 3) on the 24V bank


48V AGM bank, Lines 1 & 2

new 24V bank, line 3

I show 118-120V on all 3 legs at the inverters when the 804b is running and they are doing their job

I also put in an order for a MEP-804b AGS!!!! Once I have the auto generator start I will be able to preheat, prime and run/stop the generator without walking outside!
Still looking for a good generator controller for in the house, something wifi/bluetooth

line 3 now 6ga green wire! woohooo

Temp setup until I build generator "house" some old exhaust tubing works awesome here

My question is, when I use the gauges on the front of the machine to check what lines 1, 2 and 3 are doing I noticed something fishy

With gen running and charging battery banks
Gauges set to
Line 1 - N, I get 120V, 50% of the load at 60hz, and about 40% of the power capacity
Line 2 - N, I get 120V, 45-50% of the load at 60hz, and about 40% of the power capacity
Line 3 - N, I get 120V, 0% of the load and about 40% of the power capacity

Why does it show zero load Line 3 - N?
Is my new renogy inverter just more efficient?
It is still fast charging the lithium 24V battery bank and drawing 118-120V

 

[mciikurzroot]

Thanks for having me! This forum is full of great information about my gen set
I have been researching for a few days about this unit and its capabilities.

First off my name is Jamie, we live completely off grid in North Idaho next to a river at the base of a mountain.
We love it here! However the off grid system that came with our homestead has been needing some upgrades and changes to suit our needs.

I recently picked up this diesel genset to help repower our homestead. The house came with a Kohler propane standby generator that now with 2500 hours on it is in need of an engine rebuild
Not happy with the idea of a standby generator or chewing through so much propane each winter I have decided not to fix the kohler and to instead repower with diesel
That leads me here

I, like many before me, failed to see that this genset is 3 phase only. until AFTER I had it home
I need single phase , or I should say in order to achieve the best fuel efficiency and to keep from introducing an unbalanced load into this genset I would like to pursue actually converting this 10 wire unit to single phase
By one of two ways:

(Somebody please stop me if I am missing something)
1. Actually going inside the "head" or stator and separating the two additional wires for the 12 bolt board conversion
OR
2. Replace the AC generator with a 12 wire single phase generator

Is this possible?
I have seen it discussed many many times, but nobody has actually documented perusing either option
Here are two good threads on the issue:

Wiring my MEP-804a to run single phase

Let me start by saying I am new to this forum and am amazed by the knowledge of many on here. I recently purchased both a 004a and 804a and working/learning the machines has become an obsession. That being said, I have read many threads and understand converting the 004a to single phase...

www.steelsoldiers.com

QUOTE from that thread:
"the problem i see is that these are 3 phase only right? so if you run single phase you are just going to get 120-208
volts and use only 2 of the 3 windings, so you will only get a 10 kw genset. there is just no way around this if this
is a 10 wire gen head as i assume it is. so without replacing the gen head ( a viable option ) you have gained nothing over a mep-803"

MEP804A--Anyone have one of these?

These units are fairly "new" compared to what I own--15KW, Isuzu 4cyl diesel & 3 phase. Searched the forum but only came across 1 post & it just mentioned the 804A as a secondary item...Looking for owners of this unit...Is the engine any good? Noise levels? Can it be rewired to single phase...

www.steelsoldiers.com

QUOTE from that thread:
Its true that in a perfect world there would be no imbalance. Anytime you allow single phase loads on a multi-phase source you
WILL have phase load imbalances. What this does is causes uneven heating in coils and higher neutral currents. Normally this is a
bad thing. If the generator was wound such that each set of phase coils were organized into three quadrants each 120 degrees apart
the uneven heating would be magnified. The way these things are actually wound is the winding stagger and the angular separation is
based on the number of poles on the rotor. As an example if there were 3 coils that were 120 degrees apart the rotor would be 2-pole.
If you have a 4-pole rotor the coils will be 60 degrees apart. What this does is more closely couple the coils from a thermal perspective.
This gives you more resistance to the thermal problems that come from imbalances.

I've attached a graphic that gives you a good idea how the winding of the stator is done. This is for a motor but the basics are exactly the same.

Now.. The interesting part is even though the 804 is technically a 10 wire head it has the exact same windings as a 12 wire head.
The only difference is that 3 of the wires are connected together inside the head instead of bring brought out. What the is interesting is this
- it is theoretically possible to modify the stator to be a 12 wire setup. I've been looking around to get my hands on one (804 stator) to find
out how hard this will be able to pull off. If anyone has one, even a blown one, send it to me."


I have a 804B outside with 158 hours on it
Runs flawless and is in like new condition
I can use the 208 power I am sure, I understand this would result in using two of the 3 windings in the stator, essentially a 10K unit, not running optimum 80% of the engines load, and not getting premium fuel mileage.

I would rather actually convert this thing to single phase.
I am a mechanic of sorts and I have a custom truck shop at my house
I am not scared to take things apart and put them back together or modify machines to suit my needs


My research says the AC generator in my machine is made by Marathon Electric
single bearing
Rotating Field
Synchronous
brushless
fancooled

Coupled directly to Yanmar turbo diesel 4 cylinder


Would it be possible to simply unbolt the ac generator and replace it with a similar 1800 rpm, 15-20K power head that is single phase 240?

I would be interested in actually doing this
Many have come before me, every thread dies before it is determined how difficult it is to actually do the conversion.

Thank you!!

I have tried to read this running thread seems like back to this past February 2021 My comments will only apply to the MEP-804A/B 15kw with a Marathon generator ..It has been mentioned yes you could go in and break out T10,11 and 12, thereby giving you 12 leads and the presuming ability to configure these 12 leads into one of 2 possibilities to produce 120/240 single phase.. ..It can be done but at what price of your sanity.. In reality if you do this, there are no shortcuts to all the intent and engineering the set was designed for, just accept that your going to bastardize the set..Chris Medco did a fantastic job of doing this on the early 004 sets he made several Videos and documented it very well, but the 804 is a long way from the 004

First this 15kw generator is not like any of the other MEP generator heads, for a quick review the 802 and 803 are 12 lead so no issue, the 804 805 806 are all 10 lead, { I will not bother to even address the 807/808 sets} converting the 805 806 is relatively easy where the 804 is akin to a female dog in season, a plain bitch, well why you say ? well the end plate on the 5 and 6 are easy to remove and immediately expose the two winding sets of wires , 24 groups into 12 sets wherein the T10-12 are brought out all in one wire together, and force the set to be configured hi or lo WYE simple enuf, where it gets very hard if not impossible, in the 804 the stator windings are further inside the stator covered or blocked by the exciter rotor and stator , on the other sets the exciter Stator comes off intact with the end plate or bearing carrier, but the 804 it stays as a part of the stator housing, so no access is possible to the main windings of the actual generator is possible UNTIL you remove the carrier housing, then go forward and unbolt the flex plate from the engine flywheel , then you still have to remove the entire ROTOR assembly/shaft, its really hard and difficult to not damage the main windings or laminations. It's far easier to remove the entire Generator assembly but you can make that decision for yourself..

But moving forward get the Rotor out and away from the actual Stator body, then it gets hard, ? finding the T10-12 group of windings and breaking those apart and not damaging ANY of the other winding sets or individual wires, but for brevity sake lets assume you get this done, get you megger and DVM or 630 and find all the right wires and made back into full T10 T11 and T12 sets, then you mix up and insulate with gobs of good EPOXY mix and let it dry, then put this entire mess back together and do no harm to any of the Stator or Rotor wires and or laminations..

But now you really got a mess on your hands, look inside the control box, none or if any of it will work, as it presently exist, last I counted there are 283 individual wires going all over the place, because now you gotta wire this hot mess up for the real prize your beloved 1 phase capability .. In my experience don't fight it, take it all out and toss most of it if not all of it, but this is a debate that will not be settled and the purist among us will liken this to blasphemy , but we passed that point when we first started this effort.

It was mentioned just replacing the actual generator with something on the order of a 20 kw , but that's easier said than done you have to understand the flywheel and bell or flywheel housing are one size and several generator sizes exist, so be sure just because its a new to you generator it has to match the engine housing and flywheel or you got a new door stop for your shop ...

Honestly it is so often overlooked but for you your off grid panel just needs to be changed to a 3 phase panel, its cheap the same box enclosure will readily adapt to a 3 phase guts board, your 120 outlets work just the same your 240 fixtures will work just fine on 208 and you do some experimenting with loads and soon enuff your dead on or well close enuff and your done with all this putzing around crap of transformers and near phantom 3rd phase loads you try and create, Cris or DieselAddact gave you good advice we spend way way too much time here agonizing over the pseudo harm we think we impose on these actual generators, But do as you think fit,

 

[Guyfang]

Thank you, thank you, thank you. Could not have said it better. Or, might have said, if it works, don't screw with it.

 

[410Customs]

well explained! Thank you VERY much for the detailed description.

Earlier in the thread I/we decided there is no way in heck to "easily" convert the 804b to single phase.
So instead I took advice from this forum and ran with it, and installed a 3rd inverter, so we are now using all 3 phases.

Now with all 3 legs hooked up I was looking at the gauges and had a few questions, which I think I have answered.

The charging voltage on my new inverter was turned all the way down.... so the 3rd leg was not drawing hardly any power. I now have it turned up to 100%, the fan kicked on, the battery bank was fully charged last time I ran the generator.

So here we can see Line 1 to N

25% of the power being generated and about 42% of the rated current

Line 2 to N

about 25% of the generated power and 3-5% of the rated current at 60hz

Line 3 to N

25% of the power being generated and about 1% of the rated current

 

[410Customs]

Anyone have a thread where somebody installed auto generator start into a 804?
I have my ags and looking forward to doing the install.
Thanks!!

 

[rangerxp1000]

Look into GOOGLE the Bar Diamond or Collins connection