House Battery charging question

[dgmelp]

We own a 1996 Cutter Bus (30ft). The house batteries are new, and the MH is parked in our driveway and plugged into 30amp shore power. I would think that should keep the house batteries charged and everything working well.

The last week or so, we went in to check on things, and when we turned on the overhead 12v lights, they were very dim. Then we went to try starting the generator and it hardly turned over, as if the batteries its using to start are almost dead.

We started the engine (it started right up), and all the 12v lights became real bright all of a sudden. All this time, the unit is still plugged into shore power.

We checked the status of the batteries on the monitor and they show as charged or almost fully charged.

Help!

David

[idroba]

Your Univolt converter/charger may not be working. Check the circuit breaker for it to be sure it is on, or whatever control it may have. I am not familiar with the newer cutter busses.

If the Univolt is operating, it should be humming. Again, I am assuming the 96's still used the old Univolt system.

If it is getting 120 volt power, and is not putting out charge current to the batteries, you could have a blown 12 volt fuse in the charge circuit. Or the unit itself may be dead.

When you start the engine, the alternator takes over the charging of the batteries, which is why the brightness of the lights came up to normal.

If you checked the battery status on the monitor when the engine was running it only told you that the alternator was working to charge the batteries. BTW, the battery monitors are only a very gross indicator of the actual battery condition.

So, a few things to ponder and check.

[masseyfarm]

You have a shut off switch at the door?? Is it set active or off?
A digital meter test at the battery would confirm if charge is at that point.
Check with and without shore power.
It may be a loose or dirty terminal, as when the two house batteries are wired in series, all connections must be good to complete the circuit.
The other thought is -- has someone changed the wiring to charge the chassis batteries?
Dave

Originally Posted by dgmelp

We own a 1996 Cutter Bus (30ft). The house batteries are new, and the MH is parked in our driveway and plugged into 30amp shore power. I would think that should keep the house batteries charged and everything working well.

The last week or so, we went in to check on things, and when we turned on the overhead 12v lights, they were very dim. Then we went to try starting the generator and it hardly turned over, as if the batteries its using to start are almost dead.

We started the engine (it started right up), and all the 12v lights became real bright all of a sudden. All this time, the unit is still plugged into shore power.

We checked the status of the batteries on the monitor and they show as charged or almost fully charged.

Help!

David

[masseyfarm]

I do not see the brand name of the inverter charger?

Dave

http://www.airstream.com/files/libra...b22db48289.pdf

Not here neither.
http://www.airstream.com/files/libra...ff79168f1e.pdf

[TG Twinkie]

I would also check for a bad ground/ common connection. The vibration of the engine could cause the connection to make well enough for the lights to become brighter.

[bukib]

It is this simple...leave your unit plugged in. Turn on the aux batt switch on your dash mount. Dont turn it off until you get ready to go. Case closed. My 93 Land Yacht NEVER has discharged batteries be it coach or house.

[dgmelp]

Thanks for all the replies!

Where do I find the inverter/charger??? I looked in the battery box and bolted in there is the battery isolator made by Sure Power. But the isolator (if I'm right) only controls which batteries are allowed in the charging circuit and separates the chassis battery from the 12v circuit when the engine is off - isn't there also an inverter/charger in the system somewhere?

Again..thank you for all your help! We're learning slowly!

David

[TG Twinkie]

If you have a generator on board, it may be in a compartment close by with the transfer switch. Just a guess.