aux. batteries won't charge with shore power

Picking up a voltage meter today to check batteries with aux. switched off, plugged into shore power, and with generator running, and engine running. hopefully that will give me the readings I need. Will post results later today/Wednesday.

Thanks for your input. Not going to be able to get it to a dealer until after our Easter Trip to the lovely panhandle of Florida. T.H.Stone memorial park in Port St. Joe Florida! Can't wait, as we just got 2 more inches of snow last night in Cleveland.

Mikeborny wrote:
If I have a bad converter charger, would the batteries also not charge when the generator is running? If my house batteries charge with the generator running, but not when hooked up to shore power what could be wrong then?

The motor-home engine when running will charge the house-batteries using the alternator. It by-passes the disconnect switch.

The converter/charger is powered by 120v, ac, current. That means either shore-power or the generator running.

you have not answered any of my questions. What was the voltage reading taken at the battery-terminals?

To use my generator on my Fleetwood Class C, the shore-power cord must be plugged into a 30 amp 120v,AC, outlet box on the built-in generator.

Your Class A is supposed to automatically switch from receiving 120v,AC, power when plugged into a shore-power outlet, to receiving 120v,AC, power produced by the generator when the generator is started up (the shore-power cord should be unplugged from an outlet).

You can't have 120v,AC, from both sources at the same time.

The switch may be stuck with only 120v,AC, source being the generator.

At any rate you need the electrical system checked out by a reputable RV repair shop.

If I have a bad converter charger, would the batteries also not charge when the generator is running? If my house batteries charge with the generator running, but not when hooked up to shore power what could be wrong then?

Mikeborny wrote:
Ok, I replaced the coach batteries on Saturday and brought home and plugged into my house. I have a 30 amp rig. I have nothing but the fridge running. This morning, I checked the aux. batteries and it has lost power again. It is now down to 4 lights out of 5 when I push the Aux. battery button.

What else should I be looking for that would drain the batteries?

Why are you running the refrigerator when you are now turning the new batteries into "toast"? Turn it off and keep it off until you your battery problem figured out.

The refrigerator can easily kill the new batteries since they are not getting charged. Is the switch "on" to keep moisture from forming? Turn it "off"

Since you drove to the Ford dealer the generator would have slightly charged your old 6v house-batteries. Since they are sulfated and shot they only have very little capacity. Maybe 15 minutes or less. The guy only checked the batteries with a meter and saw better than 12.7 volts and claimed them good. Hogwash!

Did he pull them out, fully charge them, and do a load test? It would have taken most of the day. Check your bill for a "Load test".

Have you checked the circuit-breaker for the converter/charger? Cycle it off and on. Check the fuse panel to see if the fuse blew. The converter/charger may also have it's own fuse to check. When your "idiot meter" read only 4 lights it was indicating your batteries were discharging from the refrigerator being turned on and no charging coming from the converter/charger.

Have you picked up a multi-meter to check the house-battery voltage at the battery-terminals yet? It's an absolute necessity. While unplugged read the voltage at the battery-terminals. 12.7 volts would be fully charged for the new pair. I expect you to see something lower.

Plug into shore-power and make sure the "Disconnect" switch is pushed to on. Did your hear a click sound from the solenoid to indicate the batteries are now connected? Check the voltage again at the house-batteries. The voltage should rise from the initial voltage to either 13.6 volts, or 14.4 volts (bulk charging from your 3-stage charger.

If the voltage does not rise to at least 13.6 volts either the charger is not working, or the solenoid failed to connect the house-batteries.

At any rate your camping season will not start until your system is working.

If your Fleetwood works the same as my Fleetwood, the red light by the aux battery switch does not indicate if the switch is on or off. It indicates the presence of power in the 12 volt system. If you're on shore power the converter will light up the light, but the battery will be disconnected and not charge unless you turn on the aux battery switch. A lot of Fleetwood owners have ended up with dead batteries over this. The labeling of the aux battery switch and light is extremely misleading.

If you're connected to 120V with a shore power cord, the onboard converter should be maintaining battery charge.

You need to get a handheld meter to diagnose these types of issues correctly. To diagnose a non-functioning converter, connect shore power cord to 120V, place meter leads on the (+) and (-) terminals of the battery. Your meter should read in excess of 13V.

Ok, I replaced the coach batteries on Saturday and brought home and plugged into my house. I have a 30 amp rig. I have nothing but the fridge running. This morning, I checked the aux. batteries and it has lost power again. It is now down to 4 lights out of 5 when I push the Aux. battery button.

What else should I be looking for that would drain the batteries?

Not saying this is the problem, but I had a similar experience with a motorcycle battery. It would charge up on one of my three chargers and appear to hold the charge, but as soon as I put any load on it the battery output would fall well below usable. Turned out to be a bad battery.

Mikeborny wrote:
Yes, when i shut off the aux. power switch while connected to shore power all the lights go out? I am a novice when it comes to this, but I thought the shore power would bypass the aux. batteries.

Your battery disconnect switch "disconnects" your batteries from the 12v system which makes charging impossible. Toggle the switch and see if that resolves your problem.

On most motor homes the generator does NOT charge the batteries exactly.. It provides 120vac to the house systems and sub systems.. One of those sub systems is the converter, which is the device that charges the batteries.

on shore power, the very same converter charges the batteries

Possible issues: if a 30 amp rig.. I can not think of any as the converter will be on the 30 amp breaker on the generator same as the A/C and Microwave.

On a 50 amp rig.. If the Auto transfer switch is flakey and only transferring one leg to Shore (Welded contactor will do that) then it is possible the converter may not convert on shore power.

So, how does a contactor/solenoid/relay get welded? (3 names for one device).

Simply, hot switching. The proper way to transfer is to cold switch, to do this you start by TURNING OFF everything that is a big eater or... By disconnecting from shore power.. THEN you start the generator and about 1/2 to 1 1/2 minute later the box switches over, since there is no current flowing before the switch there is minimum arcing of the contacts at transfer.

With HOT switching (Fire up generator while shore power present) when it switches There is arcing both at break and make, and if there are any motors running (Air Conditioner for example) the inductive "kick" can make that one BIG arc.. Plus strange things happen at Make that increase the size of the arc as well.. The result,, Arc Welded Contacts. A very bad thing.