Battery power lost to trailer.

[facory]

Strange thing has happened. I have dual deep cycle batteries on my trailer. The batteries show that the converter is charging them. However, when I disconnect shore power I do not get any current from the batteries to the trailer. I have a disconnect switch for the batteries and it checks OK. I have opened the power panel to verify that there are no loose connections. I'm stumped.

[facory]

There is a 30 amp fuse in the hot line from the battery to the trailer. It probably blew. Replacing it should get you back in business.

[opnspaces]

I would start at the battery and take a reading from both posts. Then trace the negative wire back to the frame, Take a reading from the ground bolt to the positive terminal.

If that works out then trace the positive wire down and measure from any connections to the negative on the battery. I'm betting you'll find a circuit breaker somewhere close by that will be limiting the current flow.

[facory]

I replaced the 30 amp fuse early on. Wasn't it. Will be tackling is again when the weather clears.

[bobndot]

If you are metering battery voltage after the battery , on the HOT side and it drops to 2 or 3 volts, shouldn't it read zero if there was a break in the HOT side somewhere ? Being that there is a partial voltage reading ,
Why Not also look at the negative side ? Could this be ground related ?

Could it be a broken ground wire, caused by someone poking a pointed test probe through the wiring covering in the past to test the circuit while doing some kind of installation.
The hole in the insulation has allowed moisture to enter the wire inside, creating corrosion and maybe causing that wire to fail or partially fail ?

[Vvvv1010]

At the positive battery terminal, is it possible you have an electrical in-line fuse holder wire. 30 amp fuse might need to be changed. Just a guess.

[aftermath]

factory, you assessment is correct. 13V at the battery but 2.3V at the panel means the problem is in between somewhere. Look for a circuit breaker there or a battery disconnect. Loose connections can cause this kind of issue.

Good luck. I would be interested in hearing back from you when you figure this out. Good Luck.

If your batteries are bad they will discharge quickly but I doubt you would see a drop from 13 to 2 in the time it takes you to go make your second check.

[Sam_Spade]

facory wrote:
The power panel has the positive battery lead on one side and the negative battery lead on the opposite side. The voltage reading there is only 2.3 volts.

Some detail of this statement is NOT true.

If those leads really DO go directly back to the battery, with no fuses, switches or other devices in the line......about all that can cause that is a broken or corroded connection at one end of the cables or the other.

[westend]

Look for a circuit breaker in a small tin can near the batteries (could be attached to frame). If it has failed you may get a trickle of voltage through it. There could also be a bad connection (loose, corroded).

[time2roll]

facory wrote:
Battery voltage without park power is 13.0 - 13.3 volts. Voltage when plugged into park power 14.4 volts. The power panel has the positive battery lead on one side and the negative battery lead on the opposite side. The voltage reading there is only 2.3 volts. If the converter is charging the batteries through those same cables then I don't understand why the battery's voltage is not coming back through. My dilemma.

There is no diode in the circuit. Just copper, a fuse, switch and multiple connections that will conduct same in either direction.

If you measure 13 volts on the battery and 2 volts at the fuse panel you have a bad connection someplace or the readings are wrong. Yes very odd to consistently have same voltage when charging and 10 volt drop on battery power.

[facory]

Battery voltage without park power is 13.0 - 13.3 volts. Voltage when plugged into park power 14.4 volts. The power panel has the positive battery lead on one side and the negative battery lead on the opposite side. The voltage reading there is only 2.3 volts. If the converter is charging the batteries through those same cables then I don't understand why the battery's voltage is not coming back through. My dilemma.

[rbpru]

Like the others I suggest you disconnect the batteries and measure the voltage.

It is also not necessarily true that because they are changing they will automatically be connected to the 12 volt power distribution network.

[Sam_Spade]

facory wrote:
Battery voltage without park power is 13.0 - 13.3 volts. Voltage when plugged into park power 14.4 volts. So I know it's being sent from the converter to the battery. However, incoming voltage at the converter measure 2.3 volts.

You are confusing the issue.

The "incoming" voltage on the converter is 120 volts AC.
When unplugged from shore power, it is ZERO and whatever you measure there is meaningless.

If the batteries measure 13 volts with no shore power applied, they probably are good and the power is being lost somewhere down the line.
Start by measuring on the battery cable CONNECTORS (not the actual battery posts). If it's still good, next check the voltage on both sides of the disconnect switch. (Are you sure the switch is in the right position?)
Next would probably be checking that the negative battery cable actually has a good ground connection.
Next look for DC fuses that might be blown.

[bob213]

What is the reading at the battery posts?

[time2roll]

You need someone to look over your shoulder and verify the points of measurement.