Onan Microquiet 4000 Generator - 1999 Tioga

Issue resolved.

The ground wire coming off the back on the PowerTek Battery Disconnect relay was split into 2 lines and one of them was connected to the (+) terminal on one of the house batteries. Switched it to a (-) terminal on one of the house batteries and walla!! The aux battery switch in the on/off switch.

All lights working off the house batteries now. Generator can be started now off the house batteries. Just click the aux battery switch in the disconnect direction to disable the house batteries. click it on when you want to connect them.

Thanks for all of your assistance!

Apparently, it takes a turn of the key in the ignition to release 12 volt power to the generator. I have traced the wires. 12 volt from the starting battery runs into a compartment to the right side of the 2 house batteries. It is attached to a small electrical box with 2 connections. It is connected to one side and the 12 volt wire to the generator is on the other side. The 12 volts is not sent to the generator wire until the key in the ignition is turned on.

The 12 volt (+) wire from the 2 house batteries runs into the same compartment, but connects to a different small electrical box. This box also has a second connection. There is a red (12 volt) wire coming off it over to the 2nd connection on the first small box. It connects along with the 12 volt wire that runs to the generator.

Not sure what this area would be called or its purpose. Anyone heard of a setup like this? It has a metal cover secured by 2 screws. There are also 5 fuses - (12 volt type) located in this compartment area. They are labled as: Auxillary - (15 amp Emergency Start Switch, 5 amp Solar Panel, 3 amp LPG Detector) and Main - (7.5 amp Front Enter Center, 3 amp Solar Panel).

Is it possible that this rv is wired so you do not have 12 volts unless you have the vehicle plugged into shore power or have the vehicle/generator running?

Did some more testing this am. With the motorhome running, the vehicles starting battery measures 14.36 volts and the 2 house batteries (linked in parallel) measure 12.93 volts. Plugged into shore power (120VAC), the vehicles starting battery measures 12.43 and the 2 house batteries measure 12.93 volts.

Started the motorhome, started the generator from the switch inside the motorhome, microwave power comes on immediately. Turned the vehicle off and the generator continued to run. - (Lights, A/C, microwave, etc. - All appear to be working with generator running)

So, I stop the generator from running from the inside switch and all power in the trailer is gone. No 12 volts anywhere. So why are the 2 house batteries not being allowed to provide 12 volts to the trailer?

Those generators do not produce 12 volts, unless they are either a commercial model, or have an add on battery charger. They rely 100% on the house battery/converter for 12 volt power.

You simply need to find the break between the house batteries and the genset- they do use a 150 amp fuse fairly often.

We purchased the RV about 2-1/2 years ago and have only run the generator ourselves at home once or twice for about 15-20 minutes tops. - (With the RV motor running of course!)

* Generator Hour Meter inside the RV/On the kitchen wall say's: (1050 hrs.)

I would say the gen is not producing 12v. How many hrs on it?

Hello everyone.

Sorry it has been almost 3/4 of a year since my last post, but good news is that the generator issue is still unresolved.

I removed the coach batteries from the C-Class and measured them both.
12.21 and 12.33 volts respectively. These batteries are now 2-1/2 years old and still have a charge of over 12 volts sitting in the RV all this time. The last time we used the RV was about 2 months ago when we had it connected to shore power.

We left off where we were trying to determine why the generator only runs with the RV's engine running. One of the last posts was regarding the Battery Control Center. Not sure where to look for the breakers "Fischer" mentioned or the tiny resets. I have a wall meter in the kitchen that currently only operates when I am connected to shore power. - (Grey Tank Level, Black Tank Level, Clean Water Tank Level, Propane Tank Level, Battery Charge Level and the Generator Start and Stop Control)

Is there any chance that it has a fuse (behind it or elsewhere) that could be preventing 12 volts from passing thru it when not connected to shore power? Grasping at straws here.

Anyone willing to pick back off where "I" left off?

Sincerely,

Ken

1. You said you checked all connections. Did you check the ground off the batterys mine goes to the chassis where it is bolted. mine came loose and would not even run the lights.
2. do you have a battery control center on your coach? mine does and the gen gets its 12v from it.
3. When I start my coach I get 14v on both coach and chassis batterys that is why your gen starts with the engine running.
4. When plugged in to 120v do you get 13.6v on the batterys which is the output of the converter?
5. If you have a BCC inside there are some circuit breakers that can be reset by pressing a tiny button on the bottom. (two of the breakers are on the bottom left)

We just got home too. I'd try starting the genset now and report what happens, and measure the battery voltage after you try.

If it does the same as before, you might also try starting the genset using your method that worked, wait until it stabilizes and can provide AC power to the coach, then see if it will keep running with the Motorhome engine shut off at that point.

If it stalls out again, you might try starting it again, but flip off the battery disconnect this time before shutting off the Motorhome engine.

I am wondering if 12.33 v is just a surface charge from being plugged in and if the batteries are actually really low. I don't know if 2 deeply discharged batteries can load down the 12v output on an Onan enough to stop it's ability to make a good spark and stall it out.

Jim

Each of the 2 house batteries are currently reading 12.33 volts.
(They are connected together > + to + and - to -) - The -'s are bolted directly to the frame securely near the batteries. Not sure where the +'s go at this time. All connections are clean and tight. The house batteries are both fairly new (< 1-1/2 yrs old)

Next steps or tests I need to perform?
BTW - Thanks everyone for helping me to troubleshoot this issue.

Ken
Bethlehem, Ga.