Battery Questions

For those parked in a location without shore-power, there are other options for those with a motor-home.

Solenoids (or solid-state type) will not operate with battery voltage drops to 10.5 to 11.0 volts. Also; they can stick in temperatures below freezing, The colder the more likely. Cycling the disconnect switch on an off might free the solenoid.

The house-battery must be charged some way to a voltage above 11 volts to get the switch to function. If you have a MH life is simpler. Start the MH engine (from starting battery). There is another solenoid that will allow charging of the house-battery with the engine alternator. It by-passes the "disconnect" solenoid for house-batteries. With engine running you should see around 14.4 volts at battery-terminals of the house-battery(s) showing charging taking place.

Within about 15 minutes, or more, of engine idling the "disconnect" solenoid should function. If not you either need more heat in the MH to warm it up, or need to replace if it has failed. I have not seen any of my solid-state switches ever fail in my 2003 MH.

Generally if the House Battery switch is off the House Battery will not be charging.
Most likely the Chassis Battery is not getting charged either way.

As said by Ken... put a voltmeter on the battery terminals. 13.2+ is charging.

Adding a Trik-L-Start combiner will keep the Chassis Battery charged if needed.

If you are plugged into "shore-power" and the disconnect switch is "off" the battery-bank is off-line and cannot be charged or power the 12v circuits.

However; my MH will still power the 12v circuit through the converter so the 12v lights will work. Pull the 120v shore-power plug and you will no longer have 12v circuits working. This means if the solenoid (solid state switches in my MH) for "disconnect" switch should fail you could still camp if you got an electric site.

Roy is correct about checking voltage at the battery terminals. The voltage will increase from actual battery voltage (12.7 or less) to a higher voltage showing battery(s) are connected being charged, and able to power the circuit.

As for the chassis (starting) battery, my MH does allow charging of the battery though another solenoid using the converter/charger when plugged in. Not all MH's come set up this way. Confirmation is done by looking for increase in voltage with the meter at the starting battery terminals.

Brian - the only real way to know is to put a DC VOLTMETER on your battery terminals.

Without shorepower appllied the battery should read 12.6VDC or so if charged.

When you conenct to shore power the on-board converter/charger should operate and charge your battery. You should see the DC VOLTAGE jump up to 13.6VDC when connected to Shore Power.

Once you see 13.6VDC on the battery terminals then operate the battery disconnect switch and see if the 13.6VDC stays or falls back to the 12.6VDC reading on the battery terminal.

Another way to do this is watch your ceiling lights in the trailer that are 12VDC lights. This may not work for you if you are using REGULATED TYPE LED BOARDS.

You should be able to turn the ceiling lights 'ON' when connected to the battery and not on shore power. If you connect to shore power then the ceiling lights should get a little brighter telling you the on-board converter/charger is hitting your battery terminals.

Using the digital VOM is the better way to do this as you can read the actual DC VOLTAGE. These meters are ranging from $7-$20 (WALMART-LOWES-AMAZON-any number of Auto Parts stores). Harbor freight gives you one FREE with purchases over $25 I have heard.

I carry one of these very handy meters in my RV TOOL BOX. takes all of the guessing out of the picture...


Roy Ken