New Batteries and No Power

[kfrost72]

We put new batteries on our travel trailer and now can't seem to get any power. Power works when the trailer is set up to the generator or house power. But otherwise none at all, and the refrigerator won't even turn to the propane.

My husband said he checked and there's 12v coming off the batteries. But he's at a loss of why they aren't running the trailer.

[Mike_LeClair]

Yup, a sure sign of trouble ahead is when the "Magic Smoke" disappears from whatever device or containment that it was being held in by.

Cheers!

Mike

[MEXICOWANDERER]

A melted fuse block can be compared to a slightly smoking roof - it ain't normal wear and tear.

[kfrost72]

Thanks everyone. The cables did not get switched but dh wasn't aware of the fuse box under the tongue so in checking those he saw one looks melted. We've got power now. Just being careful till we get back to town tomorrow and can get it repaired.

[MEXICOWANDERER]

Amazing how people cannot think of using their smart phone for anything but play-toy APs. The camera. The camera.

A splotch of red paint over the positive post and on the positive cable ends also works wonders.

Firm belief that children age 13 should be mandated to take an aptitude test then get lectured about whatever weakness they exhibit. Maybe school officials who don't think of things like this should be first in line.

Testosterone blockage of the frontal lobes is pandemic. I am experienced with this as I live smack dab at ground-zero.

[NinerBikes]

If your husband reversed the wiring on the battery, his man card is revoked for 3 months.

[2oldman]

Post a picture of your battery wiring. Did you carefully make note of the wiring BEFORE you removed the old ones?

It's more likely there's zero power rather than -12v (reversed)

[RoyB]

I found the Best Way for me is to find the word 'NEG' or symbol '-' stamped on the battery case and make sure that this is the battery terminal that is going to the trailer frame ground. This will also be a larger cable.

Most all of the other cables will go to the 'positive' battery terminal connection. Especially the ones that may have in-line fuses or in-line circuit breakers.

The RV TRAILER WIRING WORLD wiring colors scheme is suppose to be BLACK for POSITIVE and SOLID WHITE for NEGATIVE. However in the AUTOMOTIVE WIRING WORLD especially around the Batteries the POSITIVE wiring color is RED and the NEGATIVE COLOR scheme is BLACK. Sometimes these two different color schemes get mixed together...

One of my trailers originally had all white cables but the SOLID WHITE color was always NEGATIVE and any white cable with a color stripe was POSITIVE.

It can very easy get mixed up. Once I know all of my cables are wired correctly I will use RED FINGERNAIL POLISH and mark the cables that are suppose to go to the POSITIVE BATTERY TERMINALS. Alot of folks use their cell phone cameras and take a photo of the battery terminals and perhaps keep this photo in a small plastic bag taped to the wall of the battery compartment.

Both the POSITIVE (+) Battery Cable and the DC OUTPUT (+) cable from the on-board converter/charger unit feeds the 12VDC Power Distribution Panel where all your DC FUSES are located... This is how the Trailer can be operated from the Battery and Shore Power connection.

When the BATTERY CABLES get REVERSED this will blow an IN-LINE fuse or trip an IN-LINE Circuit Breaker that is mounted real close to the Positive Battery + terminal. It will also blow two fuses most often located in the 12VDC Power Distribution Panel and may be labeled REVERSE POLARITY. These two Fuses will off to them-self in most cases...

First thing to do is look for these three items and know where they are located.

DO NOT replace the fuses before making the correct battery terminal wiring connections otherwise it will just instantly blow the new replacement fuse again...

Another thing I do alot doing my walk-around is measure the Battery Terminals using a multimeter without shore power connected and if the battery is fully charged it will read 12.6-7VDC across the terminals. Then when I plug-in the shore power connections I should see this DC VOLTAGE across the battery terminal jump up to 13.6VDC or higher depending what charging mode the on-board converter is in. This will tell me the in-line fuse or close by circuit breaker is OK and the REVERSE FUSES are OK. It also tells me the battery cables are connected path wise to the on-board converter/charger unit and it is charging my batteries.

Not fun finding this out when you are at your camp site and more importantly this may have your battery wiring not available for your trailer Electric BRAKES when in travel mode. This is required by DOT to provide 12VDC in the event your trailer becomes disconnected from your truck when being towed etc... This may be enforceable by DOT and even your trailer Insurance may not be work in your favor if this event happens without a properly working battery setup. You can imagine what damage a run-away trailer might cause to others.

These are some of the things I do with my original walk-around inspection before leaving my parking place.

Roy Ken

[Dick_A]

Moved from General RV'ing forum.

[bikendan]

Yep, probably reversed the battery wires, which happens a lot.

either blew the reverse polarity fuse or tripped the resettable breaker, tucked up under the trailer's A-frame. just push the little black button to reset.

[westend]

Check that circuit breaker near the tongue or front frame. It may also be inside a junction box. Some have a small button to reset the breaker.

[Mike_LeClair]

Likely batteries have been installed in reverse polarity. Probably blew the fuses on the back of the converter or blew the converter out completely. The control board for the fridge requires 12V to operate properly. Potentially damaged this control board as well although unlikely. RV wires are not colored the way that auto batteries are.

Good Luck!

Mike

[Old-Biscuit]

DID the batteries get connect backwards..........

Converter has Reverse Polarity FUSES (30A or larger on front or back of converter) that blow when battery cables are reversed.

Trace cables from battery NEG post to trailer frame.

Also Trace positive cable from battery to where it goes inside trailer.
They should be an IN-LINE FUSE on positive cable under trailer tongue that could be blown (could be a DC circuit breaker ----small box with 2 studs vs the in-line fuse, could be tripped---look for small reset button on side of it)


Last but not least.....battery disconnect switch OFF