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Bob86ZZ4 · 06-03-2009, 08:31 AM

Question about my 12 volt charging system. I have 2 deep cycle batteries for the house 12volt system. I have a Iota 55 amp charger/converter. There is a big round switch that can connect the deep cycles to the house wiring, or the 3 truck batteries to the house wiring, or all 5. United Specialties said when I'm hooked up to shore power or running the generator I should set that round switch to "both" so the charger/converter charges up all 5 batteries. If I'm not hooked up I should set the switch to run the house 12v on the deep cycles. That way if they run down I can still start the generator or truck motor. Here's my quandry. I check the voltage at the charger terminals when I'm plugged in to shore power. 13.4 volts. Right what it should be. Then I go over to the terminals by the large round switch. 12.4 volts from the deep cycle batteries. 12.8 volts from the truck batteries. I check the voltage right at the 3 truck batteries, 12.8 volts. No voltage drop from there to the back. The deep cycle voltage right on top of the battery is 12.4 volts. Voltage in the circuit/fuse center up in the master bedroom is 13.4 on the 12v side. I can see the charger has two + (red) wires coming off it. I can follow one of those up to the circuit/fuse center. I can't tell where the other one goes. It doesn't go directly over to the deep cycle/switch location. It looks like it goes off somewhere forward. It seems to me there is something wrong here. Shouldn't the voltage at the deep cycles be 13.4v when the charger is working/powered on? I don't think it's charging up my batteries properly. I would think that there should be a red/positive wire coming directly from the charger over to the switch so it would supply the correct 13.4v to whichever set of batteries I have that big round switch set on. How could the rig have gone 5 years like this if something is wrong? Did the previous owners just keep replacing batteries since they were never charged up completely properly? I don't have any history since I bought if used on a lot.

06-03-2009, 08:31 AM	#1
Bob86ZZ4 Senior Member Join Date: Feb 2009 Location: St. Paul, MN Posts: 1,819	Question about my 12 volt charging system. I have 2 deep cycle batteries for the house 12volt system. I have a Iota 55 amp charger/converter. There is a big round switch that can connect the deep cycles to the house wiring, or the 3 truck batteries to the house wiring, or all 5. United Specialties said when I'm hooked up to shore power or running the generator I should set that round switch to "both" so the charger/converter charges up all 5 batteries. If I'm not hooked up I should set the switch to run the house 12v on the deep cycles. That way if they run down I can still start the generator or truck motor. Here's my quandry. I check the voltage at the charger terminals when I'm plugged in to shore power. 13.4 volts. Right what it should be. Then I go over to the terminals by the large round switch. 12.4 volts from the deep cycle batteries. 12.8 volts from the truck batteries. I check the voltage right at the 3 truck batteries, 12.8 volts. No voltage drop from there to the back. The deep cycle voltage right on top of the battery is 12.4 volts. Voltage in the circuit/fuse center up in the master bedroom is 13.4 on the 12v side. I can see the charger has two + (red) wires coming off it. I can follow one of those up to the circuit/fuse center. I can't tell where the other one goes. It doesn't go directly over to the deep cycle/switch location. It looks like it goes off somewhere forward. It seems to me there is something wrong here. Shouldn't the voltage at the deep cycles be 13.4v when the charger is working/powered on? I don't think it's charging up my batteries properly. I would think that there should be a red/positive wire coming directly from the charger over to the switch so it would supply the correct 13.4v to whichever set of batteries I have that big round switch set on. How could the rig have gone 5 years like this if something is wrong? Did the previous owners just keep replacing batteries since they were never charged up completely properly? I don't have any history since I bought if used on a lot. __________________ '03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio