Coach Batteries

[speedman42]

I have looked everywhere and have not seen a thread on this. What charges your coach batteries. My Onan 7.5 gen will not stay runing and the codes says low voltage or bag positive conection to the batteries. My coach lights will barley come in unless I have the coach running. My generator will also not start unless I use Aux power. Any help would be greatly appreciated.

[Ramblin]

Normally, your converter charges your coach batteries when you are on generator or shore power, and your engine's alternator charges them when your engine is running.

Sounds like you may have a bad converter, or bad batteries (or both).

[lanerd]

How old are your batteries....both chassis and house. Sounds to me that they should be replaced.

As for your question... shore power (through your converter), your generator, and the engine's alternator will all charge the house batteries. On most coaches, only the generator or the engine's alternator will charge the chassis batteries. However, that said...there ARE some coaches where the chassis batteries will also be charged when connected to shore power.

Use your multimeter and measure the voltage at each set of batteries during different conditions to determine how yours is wired.

Hope this helps

Ron

[Gary RVRoamer]

You have either bad house batteries or a failed charging system for them. Either is quite possible in a 1998 coach. You should have a house battery status read-out somewhere in the coach - what does it say?

[speedman42]

The read out says nothing. When I am hooked to shore power my lights will not work. The air will run but no lights. there very dim.
does this sound like the inverter could have gone bad?

["007"]

Here are some links for 12v power systems and much more.
If your converter is OK and is putting out a charging voltage your BCO switch should always be on when using your coach and plugged into power.

[Rook]

Sounds like your Inverter is Kaput or has blown the main fuse due to a shorted battery or ??.....and also your house batteries are now completely discharged or worse.....shorted cells or just bad! That's why your DC house lights are very dim but your AC's will run when plugged into shore power. Rook

[speedman42]

Taking it to rv dealer Thursday . I will let you know what I find out

[speedman42]

Originally Posted by lanerd

How old are your batteries....both chassis and house. Sounds to me that they should be replaced.

As for your question... shore power (through your converter), your generator, and the engine's alternator will all charge the house batteries. On most coaches, only the generator or the engine's alternator will charge the chassis batteries. However, that said...there ARE some coaches where the chassis batteries will also be charged when connected to shore power.

Use your multimeter and measure the voltage at each set of batteries during different conditions to determine how yours is wired.

Hope this helps

Ron

Chassis batteries are new. THe house batteries look old to me. I just bought the motorhome so I'm not sure how old the house batteries are.
MH has been in storage since 2008.

[gemini5362]

Originally Posted by lanerd

How old are your batteries....both chassis and house. Sounds to me that they should be replaced.

As for your question... shore power (through your converter), your generator, and the engine's alternator will all charge the house batteries. On most coaches, only the generator or the engine's alternator will charge the chassis batteries. However, that said...there ARE some coaches where the chassis batteries will also be charged when connected to shore power.

Use your multimeter and measure the voltage at each set of batteries during different conditions to determine how yours is wired.

Hope this helps

Ron

Ron I am going to respectfully disagree with a part of your post. NOT all coaches have the capability to charge the coach batteries off of the engine alternator.

In my tiffin they use a special relay and I cannot remember the name of it. My bus is not here for me to go out and look at the wiring diagram to see what it is called. This relay looks at the voltage of the batteries versus the output of the alternator when it sees the coach batteries lower it energizes charging the coach batteries. On my bus shortly after I bought it I was not charging the coach batteries going down the road I thought the problem was the relay. I had Camping World check this out they told me that it was not the relay but I had bad batteries. I did not believe them but changed the batteries out as per there recommendation. ( Did it myself with Sams Club golf cart batteries) My coach batteries charge off of my alternator and allow my inverter to power my residential refrigerator with no problems now.

[Dr4Film]

Here are two links that are invaluable for newbie's regarding 12 VDC batteries and 12 VDC systems in RV's.

The 12volt Side of Life (Part 1)

The 12volt Side of Life Part 2

Now, regarding some explanations of important components within your 12 VDC system that you may or may not have. Since you have an American Dream but an older one I am not sure what components your coach will have so I will have to make some assumption.

You should have an Inverter which should also contain a converter/charger. The inverter portion will convert 12 VDC to 120 VAC to run various devices when shore power or generator power is not avaliable. The converter/charger takes care of converting 120 VAC to 12 VDC for running the 12 VDC accessories but also for keeping the House batteries fully charged.

Your engine alternator will keep your Chassis batteries fully charged while the engine is running.

Some coaches will have systems that will also cross charge meaning that when you are hooked to shore power your chassis batteries will be kept fully charged and when driving your house batteries will be kept fully charged.

If your coach does not have one installed there are alternatives that can be installed that are not that expensive. For example the Trik-L-Start, Amp-L-Start, Echo Charger, Lambert Battery maintainer are just a few that come to mind.

They are easily installed with three wires, one goes to the house battery bank, one to the chassis battery bank and one to ground.

Ultra TRIK-L-START Starting Battery Charger/Maintainer

AMP-L-START Starting Battery Charger/Maintainer - Overview Page

The LE-415 RV-Battery-Maintainer - The Product

Battery Chargers | Auxiliary Battery Charger | Xantrex

Now with all of this information you also need to purchase a decent DVOM meter for troubleshooting.

Dr4Film ----- Richard

[mel s]

Originally Posted by speedman42

I have looked everywhere and have not seen a thread on this. What charges your coach batteries. My Onan 7.5 gen will not stay runing and the codes says low voltage or bag positive conection to the batteries. My coach lights will barley come in unless I have the coach running. My generator will also not start unless I use Aux power. Any help would be greatly appreciated.

speedman
It is common/normal for the coach builder to wire the coach so ONLY the alternator charges the Chassis Batteries.

If you have an inverter with a built in charger, that will charge your House Batteries whenever you have shore or genset 120VAC power, (but not necessarily the Chassis Battery)!

My coach, as built by Safari Motor Coach, has only charged the chassis battery with the alternator for 17 years, (132K miles).
If you are having trouble holding a charge in the chassis battery I would guess you have an unnecessary draw from the battery, (or a bad battery).

Mel
'96 Safari

[jerichorick]

Originally Posted by speedman42

Chassis batteries are new. THe house batteries look old to me. I just bought the motorhome so I'm not sure how old the house batteries are.
MH has been in storage since 2008.

That is a long time for storage and have no attention. Was power to the coach during this time? At least a 20A service?

Without some basic testing no good advice can be given. Please test your batteries out of the coach. Put each of them on a charger after checking and adding distilled water to each cell as needed. Fill to the bottom of the inverted tower. BE CERTAIN that the area around each cell port is clean before opening.

After cleaning, watering and charging is complete, let the batteries rest for 24 hours and measure the voltage of each. If they or any battery is not reading around 12.6V or if there is a big difference between each battery that indicated trouble. If the voltage seems good test the specific gravity of each cell. They should all read about the same.

Lets say that you have all good batteries. Make certain that all connections are clean and put everything back together as it was. Plug in to shore power and measure the voltage across your battery. It should be 13.6V or greater. This will be from the charger. If not, check the fuse that should be located nearby.

While you have the batteries out, remove the ground cable from the chassis connection and clean it well. I use a very small amount to anti-oxide grease on my connections. Too much is not good. Reconnect and tighten securely but take care not to break the stud.

I will stop here. If you accomplish all the above successfully that will be a great place to start and to gather some valid results from.

Best wishes for success and enjoy your school of trials.
Rick

[mcshanks]

Email Fleetwood with your questions, I did and they told me my coach (2001 Discovery) was set up so that anytime my dc was 12.3 or higher my batteries were tied together.
Get a multimeter if you don't have one, best investment an RVer can make. It does look like your batteries could be history.

Fleetwoods internet site has a pdf form Manual for the 1998 American Dream that is downloadable.