Forum Discussion
RoyB
Jul 19, 2014Explorer II
A handy VOLTMETER goes along way here - They are inexpensive here $7 to $20.
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Since we camp alot off the power grid I look at my batteries using a DC VOLTMETER on a pretty good schedule. I also check my battery fluids on a regular basis as well. This is real important if you only have a single stage constant voltage converter/charger unit. These will tend to boil out your battery fluids when connected to shore power for long periods of time. Using smart mode converter/chargers helps solve this problem
Like stated above a fully charged battery will read 12.7VDC across the terminals when measured not connected to shore power. When you connect to shore power it will 13.6VDC read at these same terminals telling you your converter/charger unit is working and all fuses are good between the converter and the battery.
Like mentioned above my OFF-ROAD POPUP trailer also has a Ceiling Light disconnect plunger type switch that will disconnect 12VDC power from the ceiling lights when my fold-over sink/stove cabinet is folder over for travel. In my trailer however this only disconnects the ceiling lights and should not keep your battery from being charged.
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The weight of the fold-over sink/stove top presses down on this switch assembly when setup for camping. My plunger switch is located in the bottom right side of this fold over cabinet photo mounted to the bottom cabinet setup.
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I suspect you are going to find your trailer battery is discharged.
I also get a small trickle type charge from my truck battery when connected to my 7-pin trailer connector but this would take a very long connection period to fully charge my batteries with the truck motor running.
Just some of my thoughts
Just like in the old US western days you got to take care of the horse first. Its your only way to get back home haha...
Roy Ken
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Since we camp alot off the power grid I look at my batteries using a DC VOLTMETER on a pretty good schedule. I also check my battery fluids on a regular basis as well. This is real important if you only have a single stage constant voltage converter/charger unit. These will tend to boil out your battery fluids when connected to shore power for long periods of time. Using smart mode converter/chargers helps solve this problem
Like stated above a fully charged battery will read 12.7VDC across the terminals when measured not connected to shore power. When you connect to shore power it will 13.6VDC read at these same terminals telling you your converter/charger unit is working and all fuses are good between the converter and the battery.
Like mentioned above my OFF-ROAD POPUP trailer also has a Ceiling Light disconnect plunger type switch that will disconnect 12VDC power from the ceiling lights when my fold-over sink/stove cabinet is folder over for travel. In my trailer however this only disconnects the ceiling lights and should not keep your battery from being charged.

The weight of the fold-over sink/stove top presses down on this switch assembly when setup for camping. My plunger switch is located in the bottom right side of this fold over cabinet photo mounted to the bottom cabinet setup.

I suspect you are going to find your trailer battery is discharged.
I also get a small trickle type charge from my truck battery when connected to my 7-pin trailer connector but this would take a very long connection period to fully charge my batteries with the truck motor running.
Just some of my thoughts
Just like in the old US western days you got to take care of the horse first. Its your only way to get back home haha...
Roy Ken
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