No 12v input from battery, 2004 Terry Trailer

BEagen wrote:
Thanks for all of the advice/responses. The positive battery cable goes under the A-frame and immediately up, into the floor of the trailer. I traced it with a tracer and it is unbroken back to the power boards/center and converter. No inline fuse/junction/etc. Googled the manual for the WFCO 45 amp converter and viola! Found 2/30 amp fuses (specifically for reversed polarity) on the "back" of the unit. Access to the fuses was virtually impossible due to where/how it was mounted. Managed to dismount the unit enough to coax the fuses out. Visual and continuity tests indicated they are OK. Even cleaned the ground for the neg. battery cable. At this point I figure the (14 year old) converter is shot. Thanks to all who came to my aid. Wish it had resulted in a better (cheaper) outcome. Stay safe.

The reverse continuity fuses should be between the batteries and the converter. I would recommend taking a voltage reading from the slots in the back of the reverse polarity fuses to a good ground. This way you can measure the voltage while the fuse is plugged in.


Remember that voltage and then compare it to the voltage at the batteries. The two numbers should be very close to each other.

If you read 12.xx volts at the batteries and 0 volts at the reverse polarity fuses you have a fuse or breaker problem that you still need to find.

Another thought. if you look carefully at the circuit board the fuses are on you will probably see where the battery charge wires are soldered in. They will be bigger wires and the board might also be labeled 12v pos and 12v neg. Take a reading between these two posts. If you read 12v your wiring is good from the batteries to the board. If 0 you have a bad circuit breaker or fuse to find. If 6v your batteries are still wired incorrectly.

Hey, just think of this as an opportunity to buy an upgraded converter. The much more capable units aren't really that much more expensive if you already have to do a replacement, shelling out $30 more for a PD unit that will actually correctly charge your batteries seems like a good investment to me =)
I can't justify it on the current rig as we almost never boondocks due to tiny tanks, but if I had a bad converter I know I'd pay the extra couple bucks.

Thanks for all of the advice/responses. The positive battery cable goes under the A-frame and immediately up, into the floor of the trailer. I traced it with a tracer and it is unbroken back to the power boards/center and converter. No inline fuse/junction/etc. Googled the manual for the WFCO 45 amp converter and viola! Found 2/30 amp fuses (specifically for reversed polarity) on the "back" of the unit. Access to the fuses was virtually impossible due to where/how it was mounted. Managed to dismount the unit enough to coax the fuses out. Visual and continuity tests indicated they are OK. Even cleaned the ground for the neg. battery cable. At this point I figure the (14 year old) converter is shot. Thanks to all who came to my aid. Wish it had resulted in a better (cheaper) outcome. Stay safe.

Boon Docker wrote:

Gdetrailer wrote:



Example: DC Circuit Breaker


One should note that the breaker shown in photo IS a "self reseting" or "auto reseting" breaker (IE no reset button to push) and is typical breaker used by RV manufacturers.

HOWEVER, in order to get this breaker to auto reset, one MUST REMOVE BOTH POWER SOURCES (IE converter must be powered down AND the battery source must be disconnected from the circuit). Once all power has been removed from the circuit then and only then will the breaker reset.

Do that first before throwing parts at this.

Some misinformation above here.

What is the black button for in the image if it is an auto reset breaker?

Auto reset breakers are automatic reset, no need to power down anything.

Correct^^^^^
Small button on end is the RESET button for that CB

AUTO Reset.....resets automatically ---no need to power down/power up, no disconnecting anything thing



As to POS or NEG location of fuse or CB
Fuse goes in series with the load, to protect the power supply if the load shorts out.
Fuse/CB can be on NEG but best practice is POS so 'power supply' is shut off/
NEG side leaves DC on POS which can accidentally be grounded

Gdetrailer wrote:



Example: DC Circuit Breaker


One should note that the breaker shown in photo IS a "self reseting" or "auto reseting" breaker (IE no reset button to push) and is typical breaker used by RV manufacturers.

HOWEVER, in order to get this breaker to auto reset, one MUST REMOVE BOTH POWER SOURCES (IE converter must be powered down AND the battery source must be disconnected from the circuit). Once all power has been removed from the circuit then and only then will the breaker reset.

Do that first before throwing parts at this.

Some misinformation above here.

What is the black button for in the image if it is an auto reset breaker?

Auto reset breakers are automatic reset, no need to power down anything.

Old-Biscuit wrote:


Except -----
Fuse will be on POS cable
On the a-frame and will be a small 2 stud box...reset is typically on side of the DC Circuit Breaker

Example: DC Circuit Breaker

My circuit breaker is on the negative cable of the battery.

Old-Biscuit wrote:

Boon Docker wrote:

BEagen wrote:
2oldman: The two 6v were in series, but one was inadvertently reversed. I assume that created a reverse polarity situation. Sorry, I don't know how to post a diagram.
carringb: Wiring diagram shows a 40 amp fuse between the battery and converter but I can't find it. Believe me, I have looked and looked...
Old-Biscuit: I agree. But, cant find anything like that. No 30 amp fuses on the DC Dist Fuse Panel; just 15s and 20s.
I need to find the in-line fuse/breaker somehow. Thanks for all your comments and insights.

Follow the battery cable (likely the negative) from the battery to where it goes under the trailer look for small (approx 1" x 1.5") circuit breaker (box). Should be 2-3 ft from the battery, it may or may not have a reset button.

Except -----
Fuse will be on POS cable
On the a-frame and will be a small 2 stud box...reset is typically on side of the DC Circuit Breaker

Example: DC Circuit Breaker


Example: Reverse Polarity fuses on DC Dist Fuse Panel----40A

One should note that the breaker shown in photo IS a "self reseting" or "auto reseting" breaker (IE no reset button to push) and is typical breaker used by RV manufacturers.

HOWEVER, in order to get this breaker to auto reset, one MUST REMOVE BOTH POWER SOURCES (IE converter must be powered down AND the battery source must be disconnected from the circuit). Once all power has been removed from the circuit then and only then will the breaker reset.

Do that first before throwing parts at this.

Boon Docker wrote:

BEagen wrote:
2oldman: The two 6v were in series, but one was inadvertently reversed. I assume that created a reverse polarity situation. Sorry, I don't know how to post a diagram.
carringb: Wiring diagram shows a 40 amp fuse between the battery and converter but I can't find it. Believe me, I have looked and looked...
Old-Biscuit: I agree. But, cant find anything like that. No 30 amp fuses on the DC Dist Fuse Panel; just 15s and 20s.
I need to find the in-line fuse/breaker somehow. Thanks for all your comments and insights.

Follow the battery cable (likely the negative) from the battery to where it goes under the trailer look for small (approx 1" x 1.5") circuit breaker (box). Should be 2-3 ft from the battery, it may or may not have a reset button.

Except -----
Fuse will be on POS cable
On the a-frame and will be a small 2 stud box...reset is typically on side of the DC Circuit Breaker

Example: DC Circuit Breaker


Example: Reverse Polarity fuses on DC Dist Fuse Panel----40A

BEagen wrote:
2oldman: The two 6v were in series, but one was inadvertently reversed. I assume that created a reverse polarity situation. Sorry, I don't know how to post a diagram.
carringb: Wiring diagram shows a 40 amp fuse between the battery and converter but I can't find it. Believe me, I have looked and looked...
Old-Biscuit: I agree. But, cant find anything like that. No 30 amp fuses on the DC Dist Fuse Panel; just 15s and 20s.
I need to find the in-line fuse/breaker somehow. Thanks for all your comments and insights.

Follow the battery cable (likely the negative) from the battery to where it goes under the trailer look for small (approx 1" x 1.5") circuit breaker (box). Should be 2-3 ft from the battery, it may or may not have a reset button.

BEagen wrote:
2oldman: The two 6v were in series, but one was inadvertently reversed. I assume that created a reverse polarity situation. Sorry, I don't know how to post a diagram.
carringb: Wiring diagram shows a 40 amp fuse between the battery and converter but I can't find it. Believe me, I have looked and looked...
Old-Biscuit: I agree. But, cant find anything like that. No 30 amp fuses on the DC Dist Fuse Panel; just 15s and 20s.
I need to find the in-line fuse/breaker somehow. Thanks for all your comments and insights.

If you connected the batteries neg to negative and then connected the other two terminals to the trailer wiring, nothing would happen, power only flows in one direction.
Where the main RED battery wire connects at the rear or front of the DC fuse panel, there has to be a fuse. The fuse boards come that way. Maybe someone stuck a 20 in there.