Generator/Inverter problem '17 Dynaquest XL 37bh

[Ehyman]

We've had a number of problems with our 2017 Dynaquest XL 37BH since we bought it new two years ago, Most of which have been addressed. One annoying remaining issue, I've lived with persists.

If the generator is started while the inverter is engaged, right as the Gen is about to supply AC it over revs and faults with an over current error and sometimes stalls. The work around is to turn the generator off before starting the generator in which case it works fine. Besides being annoying, this makes using the gen AutoStart just about impossible.

I had though this was a problem with our inverter which has had problems off and on since we bought the coach, but the inverter failed completly recently...shortly after the warranty expired and the problem still remains with the new inverter removing that as a cause. I've also tested and replaced the BIRD unit with no change in behavior.

My suspicion is something is wired wrong in the breaker box and has both the Generator and inverter outputs mixed. TO test this theory, I turned off the breaker that is on the output side of the inverter and the problem doesn't present itself.

Any chance you could provide a wiring diagram for my coach so that I can verify that all is good and hopefully lick this issue once and for all? Any other ideas?

Thanks
Eric
(Last 8 of vin GHHD2458)

PS Suggestion, the inverter in my coach is mounted vertically in one of the bays. while is mounted to the side of a plastic compartment, it is secured by self tapping screws right into a frame mounted metal plate on the other side. This provides no isolation and I wouldn't be surprised if transmitted vibration helped to kill my inverter. Mount them with some vibration isolation in the future?

[CHICKDOE]

boy this is just as guess!

you say the generator is shutting down at start up and indicating it it is seeing an over current situation. i take that to mean it is seeing more load at start up than it can supply. you then say if you turn off the inverter the generator is not seeing as much load and it does not shut down at startup. the inverter does not directly use generator output. it pulls its power from the batteries. but the batteries do pull recharge power from the converter which pulls its power from either shore power or the generator. i'm just wondering if the batteries are low so that they immediately put a large load on the converter for recharge power as soon as the generator starts to supply power. plus you could have other large loads that are trying to start up at the same time such as a/c's and perhaps the electric side of the water heater.

don't know what type / size of generator you have or what equipment you have on that is putting a startup load on the generator. nor do we know what devices the inverter is powering.

this is just a thought and in no way does it consider all other possibilities.

[bclemens]

The inverters themselves have some vibration protection, most electronic devices do for this type of application.

As for the other question, I will see what my electrical engineer thinks.

I do know...if you have the AC's set to come on at the same time, that causes lots of issues with the gen A hard start capacitor will solve lots of issues.

You have to remember that when the generator finally transfers over...you're not only providing power to the charge line but also the AC's. So I would try to make sure the AC's are both OFF. And also...what do you have the charge line set for in the inverter????


I also assume you mean "turn the inverter off before starting the generator". I would retest your theory by changing the charge line to 15% or something. Also having a load test done on the batteries.

[CHICKDOE]

the interesting part of this is the mention of the generator AUTO START feature. it is supposed to start the generator due to low battery power or the need for a/c to come on to lower the temperature. so to be effective you have to leave the a/c's (both?) on as well as the converter to recharge the batteries. this could be a large startup load that the generator is reacting to. i want to believe the factory sized the generator to handle this situation. again this is just speculation but it seems to be pointing to batteries getting discharged and they are adding to the startup load. again just speculation, not scientific.

[bclemens]

The 2017 did not have a temp start for the AGS, just low voltage. And it appears that they are starting the gen manually. AGS might start the gen when needed (hopefully before depleting the batteries) whereas a manual start might have come long after.

[CHICKDOE]

Timeout! The suspicion is high startup load on the generator caused by 2 a/c’s and converter. This is suspicion. It has not been confirmed. Now we learn the generator is being started manually. Why are the a/c’s on when the generator is being started? Turn them off, start the generator, let it stabilize, then turn on one a/c, and finally the 2nd a/c.

[hook47]

OK, so I am plugged into shore power, 50AMPs, both A/C's on and I have my dog in the rig. Auto start is enabled however it can be; low voltage and/or high temp or loss of shore power. Go away with dog in rig and shore power goes out. Generator should start, correct? What about the A/C's? I presume they will shut down until power is restored by the generator, or by shore power resuming if I didn't have a generator or it wasn't auto start enabled. (I know, the shore power wont be enabled until generator is shut down) Don't the A/C's have a delay mechanism to prevent immediate restart after shutting down? Plus, I believe the generator doesn't connect to the bus until it has stabilized for a few minutes; at least that's what mine does. When manually started there is a delay before I see any ac power available.


Said a simpler way, if A/C's are turned on w/o ac power and you start the generator it will take a short delay till the generator stabilizes before providing ac power to start the A/C's? Also, my A/C's when turned on first start the fan then after a short delay the compressor starts; or at least that is what is seems to do.

[Maxwell D Pratt]

Sounds like he is overloading the Gen Set on startup. Most AC units do not have a delay on start up after a sudden shutdown. I added a delaying module hooked to a 30 amp relay. To give the gen set time to get up to speed and volts before bring it on line. Starting some Gen Sets while under a load can be fatal. I used a module that you can set the time you want the delay. I set mine at 1 minute 15 seconds. Seems to work just fine.

[bclemens]

Originally Posted by hook47

OK, so I am plugged into shore power, 50AMPs, both A/C's on and I have my dog in the rig. Auto start is enabled however it can be; low voltage and/or high temp or loss of shore power. Go away with dog in rig and shore power goes out. Generator should start, correct? What about the A/C's? I presume they will shut down until power is restored by the generator, or by shore power resuming if I didn't have a generator or it wasn't auto start enabled. (I know, the shore power wont be enabled until generator is shut down) Don't the A/C's have a delay mechanism to prevent immediate restart after shutting down? Plus, I believe the generator doesn't connect to the bus until it has stabilized for a few minutes; at least that's what mine does. When manually started there is a delay before I see any ac power available.


Said a simpler way, if A/C's are turned on w/o ac power and you start the generator it will take a short delay till the generator stabilizes before providing ac power to start the A/C's? Also, my A/C's when turned on first start the fan then after a short delay the compressor starts; or at least that is what is seems to do.

Your's, yes, that is the way it would work. But a 2017 XL is going to have a different set up. I only mentioned the AC's to see if we can narrow down the issue.

I think they said the Inverter was just replaced? did they replace the whole thing? I wonder if another part could be causing this???

[hook47]

From my operators manual:


On edit, posted just after your post.

[bclemens]

This was the response some engineering...
"Turned inverter on and both a/c’s set to cool. Started gen, one a/c turned on, Ems shed other a/c while inverter was qualifying incoming voltage before entering charge mode. Inverter began ramping into bulk charge up to 100 amps (80% charge rate which is the setting as delivered) and second a/c fired up after several minutes. Everything seems to be doing what it is supposed to. See attached 120vac wiring diagram the customer requested. If the wiring checks out ok I would want to take some voltage and amp readings to try and see what’s going."

[Ehyman]

As delivered from the factory, Both the 30amp breaker for input to the inverter and the 30amp *output* from the inverter were on the same Main bus as the 50a main in the breaker box. Moving the output breaker to the secondary bus fixes the problem.

two years of trouble finally solved. Super frustrating that this wasn't fixed when this was retuned to the factory for repair or the twice it was attempted to be debugged by a dealer and an Onan delaer since I was told it was a generator problem. Regardless, if you have similar problems, check to make sure the output and input from the inverter are on separate circuits. Can't imagine this was good for either the recently failed inverter or generator.

Thanks for the diagrams.

Eric

[bclemens]

I love it when a plan comes together Even if it is two years later.