Converter, Transfer Switch, Generator, 12 V problems, help please!

[pamerica]

I have a mess right now in my 1992 Class B.  Involves the 2 electrical systems, it seems.  The RV repair guys who are usually good, are having different ideas of what is happening, and I am hoping you folks can steer me right.

I don't know if all these problems are connected.  

I had a used generator installed about 3 years ago, onboard, Onan microlite 2800, gas.  It starts beautifully.  I got it specifically to run my roof air.  It shuts down immediately when the AC starts, yet will run a while when the fan on the AC unit is on.  However, it only runs for about 20 minutes, then shuts down.  During those 20 minutes, I can plug in AC appliances with no problem, until the generator just stops.  I do keep the refrigerator on electric, so there is a load on it from there.

I have had it in for repairs, no results. One mentioned it may be the transfer switch, which another one recently said for a different problem:  When I unplug the shore power to go somewhere and return to plug back in, the AC, and microwave light go on and off several times, and I hear a click, click, click in the converter box.  But then they settle down and run after that.  Now another fellow mentions transfer switch again.

  I am not moving my van, which I live in full time, until I learn what is causing this.  I am spending time in Florida and need the AC.

Here is the next problem:  I have a Fantastic Fan that I have used for 3 years with no problems, while running the 12 v lights, water pump, etc.  All of a sudden, 2 weeks ago, the fan and the lights started blinking, stopping, starting, until I turned the fan off.  Then the lights came back and stayed back on.

The RV guy came over the next day, said I had a burned circuit or something in the converter box and put some connection in another "leg" there.  Well, that very night, the fan and the lights just plain shut down, did not blink.  I turned the fan off, and lights came back.  So now I do run the fan about 3 hours, experimenting with it, and don't have the courage to run it any longer.  He tells me to run it until it shuts down again.  I need to ask why, if he has no idea what is happening.

One RV guy said to check the converter.  That the fan draws a lot of power from the battery, but the furnace even more.  He told me to run the furnace.  Said if it is the converter box, the furnace will drain the battery quickly and shut off, and then I will know it is the converter.

Well, after the furnace ran an hour, I called him and he told me to turn furnace off, because it is not the converter.  Folks here in the park I am at, say when a converter goes bad, it just quits.  That I wouldn't have this on and off stuff going on.

His partner comes the next day and tells me it is the converter.  I said wait a minute, your partner says it isn't.  That is when I remembered to tell him about what the AC is doing when I plug it in to shore power.  His partner had already told me that since my roof AC has a dial and not a thermostat, it does not go through the converter, goes directly to the 110 line.  I asked why then does the converter box click, click when the AC and microwave light go on and off several times until they start working?  That is when he said transfer switch.

I hope I explained this well enough to make some sense.  Do I need a new converter?  Does the fan have a short?  I can't afford a converter, to learn it was something else.  And since transfer switch was mentioned for 2 things by 2 different RV guys....

Thanks to anyone who stayed with this so far, and if you have any ideas I will surely appreciate your input.

 

[jonsun]

get a converter with a return policy.

 

[Trebor English]

When you say the Onan "shuts down" do you mean the engine stops running or does the 120 volts stop?  Does everything work the same on shore power as on Onan power?  
Where in Florida are you?  If you are in Brevard or Orlando PM me.

 

[pamerica]

Thanks, bardo.  Maybe.  Could that also solve the generator and AC issues?

 

[pamerica]

When you say the Onan "shuts down" do you mean the engine stops running or does the 120 volts stop?  Does everything work the same on shore power as on Onan power?  
Where in Florida are you?  If you are in Brevard or Orlando PM me.

Thanks, Trebor English.  The Onan quits altogether if I turn the AC on, and quits altogether after running about 20 minutes, without running the AC at all.  Just quits. 
 
Not understanding what you mean "or does the 120 volts stop?"

Everything works on shore power as well as on generator, except for the AC on the generator.  Will PM you.

 

[pamerica]

Help is on the way  

 

[Optimistic Paranoid]

Not understanding what you mean "or does the 120 volts stop?"

Everything works on shore power as well as on generator, except for the AC on the generator.  Will PM you.

I think he means, does the engine on the generator quit running, or is the engine still running but it stops producing ac?  In other words, is the problem with the engine half, or with the electrical half?

Has the air conditioning EVER worked with the generator?  How many btu's is the air conditioner?

Frankly, 2800 watts may not be enough to start a big rooftop air conditioner.  A 13,000 btu ac may need a 4,000 watt generator to run.

 

[pamerica]

Hi Optimistic Paranoid.  You asked good questions and they help me learn.

The generator quits altogether.  The engine is not running, and there is no power at all.
  
It's been a while since this all started, but I do believe the AC at one time did run on the
 generator, just for a little while.  I think maybe 45 minutes in the beginning.  Now the generator starts right up, and runs for 20 minutes with the refrigerator on, and I can plug in small appliances.  Then it just up and dies.  If I start the generator and turn on the AC, the generator gets knocked off immediately, does not run the 20 minutes.

As far as the 2800 Onan...that is the size that was originally put in it from the factory.  The roof AC was replaced about 12 years ago by previous owner.  It is now the 13,000 BTU like you said, and I don't know what the original size was.  However, I believe the generator did run the AC at one time while I have owned it.  Just for a couple minutes, though.  So maybe that is part of the problem, like you suggested?  Maybe the generator is not big enough for the roof AC.  But why does it only run for 20 minutes and stop, even without the AC on?

Thanks again, OP.

 

[jonsun]

it probably has a voltage shutdown or an over-heat shut down. but also those things get vapor lock im told.

 

[tx2sturgis]

I think you have a couple of issues, we need to isolate them as best we can.

First, check the oil level in the generator, to make sure its not being shut down by the low oil sensor.

Next have a look at this chart:





According to the chart, it could be low oil level or a maybe a faulty fuel pump or blocked air flow.

Also, the 2800 might be having a problem running that much AC, but if you want to try something, turn off the refrigerator and then start the AC unit when the generator is already running for a minute and shore power is disconnected.  

As far as the converter, they tend to be problematic when old, but be sure to check the water levels in your house and starting batteries, and also the terminal connections on those batteries. If they are not shiny and silvery looking, they need to be cleaned up. Corroded and/or loose battery connections can cause a lot of the problems you are having on the 12v side.

The older style convertors tend to dry out batteries...so you might consider a more modern converter. But check the batteries and the connections to them.

 

[Optimistic Paranoid]

As far as the 2800 Onan...that is the size that was originally put in it from the factory.  The roof AC was replaced about 12 years ago by previous owner.  It is now the 13,000 BTU like you said, and I don't know what the original size was.  However, I believe the generator did run the AC at one time while I have owned it.  Just for a couple minutes, though.  So maybe that is part of the problem, like you suggested?  Maybe the generator is not big enough for the roof AC.  But why does it only run for 20 minutes and stop, even without the AC on?

If a generator isn't big enough - enough power - the air conditioner won't start.  If a genny can start an ac, it usually can run it just fine.  Unless another heavy draw item tries to come on at the same time.  A lot of RVs have an either/or switch marked AC/Microwave.  You can run one or the other, but you can't run both at the same time.

It does sound more and more like a generator problem, possibly heat related.  Do you have an operator's manual for the genny?  If not, maybe you can find one online.

 

[pamerica]

Thanks bardo, tx2sturgis, Optimistic Paranoid for your information.  A tribe member is coming to troubleshoot.  We will consider all of your suggestions.  I appreciate your time.

 

[Trebor English]

Purrwin, the kitty, and his person, Pamerica, now have reliable air conditioning, a functional generator, and an overhead light.  It really was quite simple.  The process is A) diagnose, then, B) change broken parts, then C) retest..  With multiple problems, A, B, C, lather, rinse, repeat.  It is important to chase one ghost at a time.  I apologize in advance for the length of this post.  There may be nuggets useful to someone else.  It took me two days to do this stuff so maybe a long report is OK.  That's my excuse anyway.  If you want to reply to this please do not quote the whole thing.  It is too long.  

What made it difficult with this case was the importance of keeping the 120 volts alternating current connected so the air conditioner would keep working.  The RV had not been driven several weeks because after unplugging from the campground reconnecting was erratic and getting worse.  What I did was go after the generator first.  There was a wire from the Onan to the transfer switch.  Halfway between there was a 4" box with a splice in it.  I replaced the splice with a 2 pole 30 amp switch and a duplex outlet.  That permitted testing the Onan with the switch off to have no effect on the rest of the system.  It started and ran OK.  I had brought a hair dryer (1800 watt) a space heater (1000 watt) and a window unit air conditioner (500 watt running, 1500 starting) and a Kill A Watt to test with.  The generator worked fine for an hour and a half running all the combinations that a 2800 watt generator ought to run.  There was no 20 minute issue and no full load issue.  

The transfer switch never saw the Onan run due to the isolation switch I installed.  The shore power was still connected and the air conditioner was running.  The unplugging from shore power and reconnecting should have left the transfer switch relay in the deenergized shore power position.  There ought to be no issue there.  The transfer switch box was warm to the touch.  I thought maybe it was wired so that the relay turned on with shore power and the relay coil was making the box warm.  That would account for the problem reconnecting if the transfer switch had bad contacts.  Not having a replacement switch and the late hour I left with the plan to come back with a transfer switch, manual, automatic, or something that could keep kitty cool.  The evidence for a bad transfer switch was weak but I was reluctant to touch it without a spare switch to keep the air conditioner cool.

I got a transfer switch.  The one I got, a nice one, has a delay circuit so that 30 seconds after the generator comes on it switches from shore to generator.  I went back a week later with part in hand.  I explained that plan B is to connect shore power directly to the coach and bypass whatever is necessary so that there would be air conditioning before I left.  Plan A was to replace the transfer switch and test all the combinations.  When I opened the old transfer switch the problem was obvious.  One of the contacts was so pitted that it had made some heat.  The wire to the ring terminal had suffered enough and fell off.  The new transfer switch made everything work as it should.  The Onan, a week later, still starts and runs OK.  After a couple of minutes no load the surging settled down, 58 hertz, too slow but good to test with.  The shore breaker and air conditioner were off.  I flipped the isolation switch on connecting the Onan and 30 seconds later, click, the desk lamp came on.  After the air conditioner had been off 5 minutes its switch was turned on, the Onan growled and the air was cold.  Just for assurance there was another disconnect, reconnect.

The 12 volt overhead light was easier.  It had two switches.  The one at the light is the normal control.  The switch at the wall was never used, just left on.  Now, with some water damage, the wall switch won't move.  The ohm meter says it is open even though it is in the on position.  The quarter inch spade quick disconnects got unplugged from the switch and I connected them to a brand new SPW.  That's a short piece of wire.  It has the right ends crimped on it.  The SPW can't turn off but since the overhead light has a switch at the light there is no problem.  The other overhead light all the way in the back seems to have an intermittent connection.  With the SPW it works but I have seen it not work.  The big wad of wires in the wall didn't respond to pulling and squishing and wiggling.  The back light seems to just work now.  Maybe the intermittent connection is somewhere else.  

The fan is still broken.  There are no volts coming in to it.  I thought, since it is between the two overhead lights, it might have tapped into that.  It seems not to be the case.  Pulling on wires it seems they are not connected in the ceiling.  It is a separate issue.

Since the engine hasn't been run for now another week I hooked up the battery charger.  If the starter battery is low it is more gentle to give it a few amps before trying to start the engine.  I found both plus and minus cable clamps were loose.  They got tightened.  

I located the solenoid switch that controls alternator charging of the house battery.  The concept of jump starting the van using the solar powered house battery and how to do it was explained.  Part of what I wanted to accomplish was to provide information.  Pamerica now has a voltmeter and she knows how to use it.  The concept of one dead battery and one good one, the ability to jump from one to the other, how to tell which battery is dead and the understanding of it all takes the magic out.  I don't mean to disparage people who repair RVs but Pamerica has had 6 in a row who cost her a lot of money and serious inconvenience.  You can look at Handy Bob's web page to see how so many solar people get it wrong too.  These RV systems are exactly like regular house systems except different.  Regular house repair people are the same.  Some just don't understand what they are working on or they know things that aren't quite so.  

It is not known whether the Onan is started by the house battery or the engine battery.  Pamerica needs to know so that when things don't work she can figure out what to do next.  My plan is not that she will have to fix everything to remain mobile.  When something breaks she will need to tell the idiot who comes to change parts which part to change.

 

[Trebor English]

Question: in a class B is the generator electric start normally connected to the engine start battery or the house battery?  When Coachmen built the thing 25 years ago it had both batteries so it could be either.  Is there a standard?

 

[highdesertranger]

that's a good question. I don't have a lot of experience with built in generators. you would think it would be the house battery because it's closer to the genny. but if you killed your house battery you couldn't start the genny. couldn't you just disconnect the engine battery and see if the genny starts? BTW good Karma your way Trebor. highdesertranger

 

[jonsun]

disconnect starting battery and see if it fires up

 

[tx2sturgis]

Wow!

Great effort and great results!

 

[tx2sturgis]

Question: in a class B is the generator electric start normally connected to the engine start battery or the house battery?  When Coachmen built the thing 25 years ago it had both batteries so it could be either.  Is there a standard?

Do the interior lights dim when the Onan fires up?

On my 1987 they did.

Mine normally cranked from the house batteries, but it also had a factory installed switch on the dashboard that engaged a solenoid to either bridge the house batteries to the starting battery or isolate them from the starting battery. This was so you could give either battery a charge from whatever engine was running at the time.

 

[rvpopeye]

Manufacturers have no set rule as to which battery to start the genny.

Typically it's the house battery but sometimes the genny is in the front of the rig and it makes sense to use the starter battery..??

In a class B that could go either way.

I would go with the suggestion of disconnecting one battery and trying to start the genny method of finding out.....

Also agree that the older converters are UPS's.
Mine has been unplugged in every one of my rigs that had one.

Solar did the job in both rigs but sometimes that just wasn't enough (75w panel)so....
In my class A ,I just charged the house battery from the alternator or when staying in a campground or boondocking used an automotive charger.