Sidewinder

My friend has a 1994 Fleetwood motorhome (new to him) with an Onan 4000 watt generator. Whenever he uses the RV the "house" battery will eventually go dead. The generator is always running so I would think that the generator should power anything that needs 12V (like the lights) AND charge the battery while it is runnung. This does not seem to happen.

Is the generator supposed to provide 12V and charge the battery while it is running? I have tried searching online but I can not find anything that explains how thhe generator is supposed to work.

Also once the house battery is dead the generator will not start BUT if he starts the RV's engine he can then start the generator right away. Obviously it uses the starting battery only if the engine is running. Does anyone know how this works (wiring diagram)? It does not have a regular isolator but it does have a bunch of things wired together underthe hood. Any ideas?

Thanks!

jrs_dodge_diesel

That all depends on how it was wired, and the accessories that came with the motorhome. See if you can find any documentation on the vehicle, including the wiring schematics. That would show you everything.

staarma

My gen charges the batts in my toy hauler. The best way to see it happening is look at the battery life on the monitor without the gen running. Then crank up the gen and look again. It goes from 2-3 lights to the full 4 lights at 100%.

phabib

Typically the device that powers the 12V devices from 120V, the converter/charger will also charge the battery. The problem is that the converter that comes with just about every RV is pretty poor and will take several days to charge a dead battery, and even then doesn't provide enough voltage to get a full charge. The thing to do is to replace the stock converter with a good one.

Progressive Dynamics makes a good one that can deliver some real current to the battery and also has intelligent charging. These guys will charge a dead battery in a few hours instead of days, while also providing more power to run your 12V loads.

One of the first things I replaced in both of the RVs I've owned.

Texasimport

Yep it should charge the battery if not something is wrong. . .yes the display gives clues but to be 100% sure put a voltmeter on your battery and measure 12 volts or so before the gen is turned on. Once running you should see something closer to 13 or higher. You now know your gettin that charge.

Bark

As has already been sort of said. Something is wrong. My current Intelli-Power converter (Progressive Dynamics) can put out up to 60 amps for awhile and does a great job of charging the batteries.

JPR Ram

My slide-in camper batteries will charge running a generater, plugged into a shore line (they use the same power cord) or when the truck is running. It's all about how the converter is wired up. It does sound like there is a problem with you friends converter to me.

FiverBob

Pretty easy to track down. Turn on the generator, pull the plug out from the converter and check the outlet it is plugged into and see if it has 120v. If not, track it back and find out why not. My Winnebago had two dash switches that allowed for different options for connecting or isolating house batteries to engine batteries, even running the engine on the generator if the alternator went out on the engine. Possibly he is not setting one of those switches in the right position when running on the generator if he has them.

Bob

Bark

Good thinking FiverBob.

Sidewinder

Thanks for all of the replies! I did check the voltage on the battery and started the generator - no change in the voltage so I guess it is not charging! The AC voltage is working fine.

This RV generator is new so I might be missing something obvious.

If we start the engine the battery does charge off of the alternator, so something is wrong. There is no switch to select batteries ( I have one in my boat so I know how they work) but there is a button on the dash of the truck labeled "AUX. START" and a disconnecting switch directly on the starting battery that seems to shut off everything. If the starting battery is connected and I press the switch I can hear what looks like a starter solenoid clicking. I THINK this connects the house battery to the starting battery.

It would be great if I could find a wiring diagram for this thing so I could figure out what all of the relays or diodes or whatever they are do. I have been searching online but so far I haven't seen anything similar.

Any more ideas are welcome! How can I check or fix the 12V DC part of the generator??

phabib

You're right about the Aux start. It allows you to start the engine from the house battery if you drain the engine battery.

Do you have power to the converter? If no, fix it. If yes.

Is the converter putting out power. if no, get the PD converter. If yes, your battery should charge.

FiverBob

Interesing statement - - the alternator from the motor is not charging the batteries either. I have a feeling some relay is not closing and there are so many configurations from different manufacturers it is hard to advise you what to do. If you are not charging from the engine, it is obvious the problem is not isolated to the generator.

CarlJensen

Kind of a long address but this site has a diagram for the unit a lot of RV's use and an explanation of where things are at. Don't know if it will help but here it is ... As said they are not very good.

http://www.hayseed.net/~jpk5lad/RV%2...converter.html

Here is a link for a place to get a better unit if you need it.

http://www.bestconverter.com/Progres...ower_c_81.html

Sidewinder

Sorry if that wasn't not clear. I even started confusing myself. It does charge from the alternator with the engine running - no charge from the generator.

Also I meant to say that the generator thing is new (the generator itself is as old as the RV).

Sidewinder

Thanks! Looks like some good info!