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Author Topic: 8.5kw onan issues  (Read 359 times)

pacer1955

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8.5kw onan issues
« on: September 30, 2017, 02:34:41 PM »
Hello,

Re: 8.5kw onan in 2005 Monaco Knight

I'm able to start the generator while plugged into 50a shore power, but it just clicks and light dims when trying to start with shore power off. The 2 chassis batteries are not very good, but the 4 house batteries are good (6 months old refurbished). Does the generator use the chassis batteries for starting when shore power is off, but use house batteries for starting when plugged into shore power? This is confusing.

Also, I made the mistake of not starting the gen. for 6 months during the hot summer, so now when it does start it revs up then quits. After about 4 or 5 times (restarting & quiting) it runs normal. I have no way to extend the delay time (for generator to send power to coach) so power is being applied to electronics during the reving up & down & quitting. Should I have the carburetor rebuilt? This generator does not slide out of the front, its stationary so not sure how big the job would be to fix. (this has about 200 hrs on it)
« Last Edit: September 30, 2017, 03:07:05 PM by pacer1955 »

Gary RV_Wizard

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Re: 8.5kw onan issues
« Reply #1 on: September 30, 2017, 03:17:03 PM »
The generator starts from the same batteries no matter what the situation. However, when shore power is present, the converter/charger is there to assist the batteries (charging them), so power is readily available to crank the genset.

Gensets may be wired to start from either house or chassis batteries and I'm not sure which was chosen by Monaco for your coach, but it seems the house batteries are the most likely.  Hopefully another Monaco owner can help answer that. If it is the house batteries, they seem to not be as good as you think. What does "refurbished" mean with respect to your batteries?  Some old battery that is claimed to have been resurrected from the dead? I would be extremely skeptical of that...

You can use the Aux Start (emergency/Boost) switch on the dash to couple house and chassis batteries for starting either engine or genset.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

pacer1955

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Re: 8.5kw onan issues
« Reply #2 on: September 30, 2017, 08:10:42 PM »
If it is the house batteries, they seem to not be as good as you think. What does "refurbished" mean with respect to your batteries?  Some old battery that is claimed to have been resurrected from the dead? I would be extremely skeptical of that...

You can use the Aux Start (emergency/Boost) switch on the dash to couple house and chassis batteries for starting either engine or genset.

I purchased them from Interstate directly (they have a warehouse here in vegas) don't know what they mean by "refurbished" but they only charged me $50 each and claimed they should work as good as new. Prior to purchasing them 6 months ago, the generator would not crank at all with the old batteries, so I agree these generators require good batteries to start them (a reading of good voltage is not enough)  I have a cheap 12 volt 500amp pile load tester but it can test up to 1000 cca so i should be able to connect 2 6 volt batteries in series properly loaded to find out if they're junk already.

I knew the boost switch could be used to crank the main engine, but didn't know it could also be used for starting the gen. Will have to try that.
« Last Edit: September 30, 2017, 08:17:15 PM by pacer1955 »

Ernie n Tara

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Re: 8.5kw onan issues
« Reply #3 on: October 01, 2017, 08:19:49 AM »
Apparently your used batteries had six months use left in them TANSTAAFL. The boost may help, but it sounds as if new batteries would be the real answer.

Ernie

Low battery voltage could also be contributing to to your running problem, but it sounds like you really need to be running the generator more often.
« Last Edit: October 01, 2017, 08:22:59 AM by Ernie n Tara »
Ernie 'n Tara

2011 Winn Journey 34y
2012 Jeep Rubicon - Dozer (orange - kinda)
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RedandSilver

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Re: 8.5kw onan issues
« Reply #4 on: October 01, 2017, 10:01:32 AM »
Quote
but they only charged me $50 each and claimed they should work as good as new.

If this is true - why would anyone need new batteries?

It's often true that you get what you pay for.


Not sure why you are starting the generator while hooked to shore power.  I don't think I have ever done that.
The generator is for use when there is NO shore power.  But if yours will only start with shore power - I guess that's your problem.
 
Have to tried to start the generator while the main engine is running?  The alternator should supply some voltage and might
help it start - worth a try?

2002 Rexhall Rose Air  Cummins 8.3  350hp

Gary RV_Wizard

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Re: 8.5kw onan issues
« Reply #5 on: October 01, 2017, 01:23:06 PM »
My guess is that those are batteries that Interstate took back for one reason or another from a retail dealer and wanted to dispose of them. For example, they might have been used in a demo, or loaned to a charitable event, or returned as part of a warranty claim.  They were no longer "new", so they call them "refurbished" (which has no legal definition). If they didn't give you a warranty with them, that "refurbished" claim means essentially zero.

Be aware that Interstate doesn't make batteries and that Vegas warehouse is just that: a building full of batteries to be sold. They probably have no battery engineers, lab equipment or even trained battery techs.

I suspect your load tester will show a severe voltage drop under load.  However, make sure the cells have adequate electrolyte (add distilled water if needed) and the charge is full (12.6v for the pair) before testing.
« Last Edit: October 01, 2017, 01:27:44 PM by Gary RV_Wizard »
Gary
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pacer1955

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Re: 8.5kw onan issues
« Reply #6 on: October 01, 2017, 02:45:17 PM »

Low battery voltage could also be contributing to to your running problem, but it sounds like you really need to be running the generator more often.Ernie
How can low battery voltage affect how the generator is running? I assume once the generator starts the batteries are no longer relevant. The running problem started the first day I put those batteries in and was finally able to start the gen after 6 months. The batteries were tested good before I purchased them. I believe the running problem may be carb related.

If this is true - why would anyone need new batteries?
It's often true that you get what you pay for.
Not sure why you are starting the generator while hooked to shore power.  I don't think I have ever done that.
The generator is for use when there is NO shore power.  But if yours will only start with shore power - I guess that's your problem.
Have to tried to start the generator while the main engine is running?  The alternator should supply some voltage and might
help it start - worth a try?

I agree in many cases you get what you pay for, but people also over pay for things. Faced with needing 6 new batteries (2 chassis + 4 house) with a quote of $1000+ I was researching used batteries with a warranty (which I did get) I can't recall now if the warranty was 6 or 12 months, but if they fail a load test I'll be calling them. The generator should be started and run under load every so often whether you need it or not- whats the difference if i started it with shore power connected or not? No, I haven't tried starting the gen with main engine, but I don't believe the alternator charges the house batteries.


Be aware that Interstate doesn't make batteries and that Vegas warehouse is just that: a building full of batteries to be sold. They probably have no battery engineers, lab equipment or even trained battery techs.

I suspect your load tester will show a severe voltage drop under load.  However, make sure the cells have adequate electrolyte (add distilled water if needed) and the charge is full (12.6v for the pair) before testing.
its called "Interstate All Battery Center" and they do have some test equipment. Even though its a big facility, it may just be a reseller I'll have to check into it further.

Ernie n Tara

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Re: 8.5kw onan issues
« Reply #7 on: October 02, 2017, 07:29:58 AM »
In at least some cases, and I suspect most, the generator itself does not have its own battery.

Ernie
Ernie 'n Tara

2011 Winn Journey 34y
2012 Jeep Rubicon - Dozer (orange - kinda)
2006 Jeep Wrangler

Gary RV_Wizard

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Re: 8.5kw onan issues
« Reply #8 on: October 02, 2017, 09:26:07 AM »
Quote
its called "Interstate All Battery Center" and they do have some test equipment. Even though its a big facility, it may just be a reseller I'll have to check into it further.

I think the "All Battery Centers" sell and install retail as well as distribute to smaller Interstate dealers. My main point was that they are just a battery store and likely no more skilled than any other. Interstate's primary expertise is in selling batteries.
« Last Edit: October 02, 2017, 09:29:59 AM by Gary RV_Wizard »
Gary
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Gary RV_Wizard

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Re: 8.5kw onan issues
« Reply #9 on: October 02, 2017, 09:34:36 AM »
Quote
How can low battery voltage affect how the generator is running? I assume once the generator starts the batteries are no longer relevant.

The Onan diesel you have needs constant 12v power for fuel pump and control circuits. In an RV, it relies on the vehicle battery system both to start and maintain running voltage. Few modern RVs have a separate battery or 12v charging system for the genset - it uses either the house or chassis 12v system.
Gary
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utahclaimjumper

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Re: 8.5kw onan issues
« Reply #10 on: October 06, 2017, 04:39:40 PM »
 It also does not have a carburetor.>>>Dan
38' American Tradition 38TT/330 turbo Cummins
Jeep liberty 4 down
72 VW Baja 4 down
Cedar City, Utah
USAF vet. 59-63
The difference between intelligence & stupidity is: intelligence has it's limits
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Lou Schneider

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Re: 8.5kw onan issues
« Reply #11 on: October 06, 2017, 05:47:26 PM »
I haven't tried starting the gen with main engine, but I don't believe the alternator charges the house batteries.

It should, there should be a solenoid connecting the house and vehicle batteries together when the main engine is running so the alternator can charge them both.

One reason the generator is on the house batteries is the engine's control circuits (and ignition if it's a gas generator) consume some 12 volt power.

The generator does not have a 12 volt output, instead it's 12 volt power is provided when the generator's 120 volts feeds the converter, which provides 12 volts to the house batteries.

The converter usually doesn't charge the chassis battery, if the generator was connected to it repeated starts and extended running would drain the battery.
« Last Edit: October 06, 2017, 05:52:38 PM by Lou Schneider »

pacer1955

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Re: 8.5kw onan issues
« Reply #12 on: October 06, 2017, 07:21:43 PM »
The Onan diesel you have needs constant 12v power for fuel pump and control circuits. In an RV, it relies on the vehicle battery system both to start and maintain running voltage. Few modern RVs have a separate battery or 12v charging system for the genset - it uses either the house or chassis 12v system.
Ok, that's good to know. I just replaced both chassis batteries, and will be replacing 2 of the 4 house batteries which failed the load test. All 4 house batteries were about 2 quarts low on water (each) and the cells were full less than a year ago. The magnum invertor must have been overcharging the house batteries causing the water to boil at the 30a intellitec setting. I've since lowered it to 15a. Have to check the water level often. If low house battery voltage is causing the gen to keep quitting & have to be restarted several times that would be a simple fix.

It should, there should be a solenoid connecting the house and vehicle batteries together when the main engine is running so the alternator can charge them both.
One reason the generator is on the house batteries is the engine's control circuits (and ignition if it's a gas generator) consume some 12 volt power.
The generator does not have a 12 volt output, instead it's 12 volt power is provided when the generator's 120 volts feeds the converter, which provides 12 volts to the house batteries.
The converter usually doesn't charge the chassis battery, if the generator was connected to it repeated starts and extended running would drain the battery.
I wasn't aware of this. Next time I start the main engine I'll check the house battery voltage (before & after) to see if our model has that selenoid, (gen is diesel)

It also does not have a carburetor.>>>Dan
If 2005 onan 8.5kw diesel has no carburetor then why else would it start then quit several times before it stays running smoothly? Could weak house batteries cause those symptoms? (revs up then quits several times)
« Last Edit: October 06, 2017, 07:31:31 PM by pacer1955 »

utahclaimjumper

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Re: 8.5kw onan issues
« Reply #13 on: October 06, 2017, 07:59:33 PM »
Diesel engines use fuel injection systems ,,not carbs as Gassers do. Just because you have no carburetor does not mean you don't have fuel problems,,make sure you have enough fuel in the main tank for the generator to draw from and run it often to maintain "prime" in the system.>>>Dan
« Last Edit: October 06, 2017, 08:04:56 PM by utahclaimjumper »
38' American Tradition 38TT/330 turbo Cummins
Jeep liberty 4 down
72 VW Baja 4 down
Cedar City, Utah
USAF vet. 59-63
The difference between intelligence & stupidity is: intelligence has it's limits
      Albert Einstein.
President Western GM Coach chapter FMCA

pacer1955

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Re: 8.5kw onan issues
« Reply #14 on: October 06, 2017, 08:41:15 PM »
Diesel engines use fuel injection systems ,,not carbs as Gassers do. Just because you have no carburetor does not mean you don't have fuel problems,,make sure you have enough fuel in the main tank for the generator to draw from and run it often to maintain "prime" in the system.>>>Dan
It ran pretty well until I couldn't get it started for 6 months. (onan tech gave wrong info over the phone-correct reason for not starting was weak house batteries not starter etc. Lesson learned - battery voltage has very little to do with battery being good or not) When I finally replaced house batteries & got gen started, running problem described above started. (always kept minimum of 1/2 tank fuel)
« Last Edit: October 06, 2017, 08:45:38 PM by pacer1955 »

Gary RV_Wizard

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Re: 8.5kw onan issues
« Reply #15 on: October 07, 2017, 11:39:59 AM »
Quote
The magnum invertor must have been overcharging the house batteries causing the water to boil at the 30a intellitec setting. I've since lowered it to 15a. Have to check the water level often.

This is a chicken & egg problem and probably not the fault of the Magnum.  When the water in the cells begins to get low, the battery doesn't charge fully so the charger keeps trying. That heats up the battery, causing more evaporation and a vicious cycle continues. Many newer & better quality chargers try to detect this situation and either cease charging after several hours or simply shut off, but it's hard to reliably distinguish a severely discharged battery from a defective one. I believe your problem started with at least one bad cell in one or two batteries and the situation deteriorated from there.

Replacing just two of the 4 batteries is risky, since they are probably going to respond to charging differently than the new ones. The condition of the other two older ones has to be suspect after finding two bad ones. Keep a close eye on water consumption and battery temperature. Remove any battery that seems to get hot or shows rapid water loss from any cell.

Not sure what "30A Intellitec setting" you are referring to, but I doubt if it has any effect on charging. The Intellitec 30A load management system is not part of the charging control.
« Last Edit: October 07, 2017, 11:44:48 AM by Gary RV_Wizard »
Gary
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utahclaimjumper

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Re: 8.5kw onan issues
« Reply #16 on: October 07, 2017, 11:57:14 AM »
 Carefully check the oil level and coolant level in the generator,, these can be touchy.>>>D
38' American Tradition 38TT/330 turbo Cummins
Jeep liberty 4 down
72 VW Baja 4 down
Cedar City, Utah
USAF vet. 59-63
The difference between intelligence & stupidity is: intelligence has it's limits
      Albert Einstein.
President Western GM Coach chapter FMCA

pacer1955

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Re: 8.5kw onan issues
« Reply #17 on: October 07, 2017, 03:31:05 PM »

Not sure what "30A Intellitec setting" you are referring to, but I doubt if it has any effect on charging. The Intellitec 30A load management system is not part of the charging control.
Inside the RV on the intellitec panel (where you turn on/off invertor & charger) there's a button called shore with dial to the right. When you press shore then rotate dial the amps change from 30 to 20, 15, and 10. Lowering the setting seems to lower the output, but I wonder what type of test equipment I would need to test the actual amperage coming from the charger? I have a clamp meter for testing ac amp draw but not sure if that would work (its a $14 unit)

I was just about to purchase 2 new house batteries this morning but thought I would check the 2 bad batteries with the hydrometer just to make sure the cells were still showing bad. I was surprised to see that today the cells are no longer in the center of the red "bad" section but are now in the lower part of the gray "Fair" section (hydrometer reads either good,fair,bad). It seems they are slowing coming back so I'm going to hold off on the purchase for a few more days and recheck with hydrometer, and run new load tests at that time. Hopefully they continue to improve & there's at least 12 months of life left in them. I initially tested these with the hydrometer 15 minutes after adding water, then 12 hours after.
« Last Edit: October 07, 2017, 03:37:05 PM by pacer1955 »

Lou Schneider

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Re: 8.5kw onan issues
« Reply #18 on: October 07, 2017, 04:08:18 PM »
Inside the RV on the intellitec panel (where you turn on/off invertor & charger) there's a button called shore with dial to the right. When you press shore then rotate dial the amps change from 30 to 20, 15, and 10. Lowering the setting seems to lower the output, but I wonder what type of test equipment I would need to test the actual amperage coming from the charger? I have a clamp meter for testing ac amp draw but not sure if that would work (its a $14 unit)

That clamp on meter won't measure the DC current going into the batteries, but you can get a close approximation by using it to measure the AC current going into the coverter/charger and multiplying the reading by 10.  1 amp at 120 volts = 10 amps at 12 volts.

If you can't get to the converter's AC input wires, turn off everything else in the RV (easiest way is to turn off the circuit breakers) and clamp the meter around one of the incoming AC lines.  With everything else off, the current you see should be what is going into the converter.
« Last Edit: October 07, 2017, 04:15:48 PM by Lou Schneider »

Gary RV_Wizard

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Re: 8.5kw onan issues
« Reply #19 on: October 08, 2017, 10:59:44 AM »
To the extent that the Intelletec panel controls things, it is working with incoming 120vac voltage and amps. That has little to do with battery charging amps. The charger runs off 120v power, but 1 amp @ 120v enables it to produce 10 amps at 12v, so even at the Intelletec 10A setting the charger could produce as much as 100 amps for battery charging.

Intelletec makes a variety of energy management products, so I'm not sure exactly what you have. It sounds, though, like a shore power management system that can shed loads to keep total power consumption to some max amount, anywhere from 10A to 30A. That would not limit charging at all.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

 

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