Trailer batteries are not charging from my vehicle.

[dbbls59]

Trailer batteries are not charging from my vehicle Followup.

They do charge when hooked to shore power but will not charge while towing with the truck. There is power at the vehicle plug but it will not go into the trailer. Any suggestions?
The reason I don't think the batteries were charging is because I use to be able to leave my batteries disconnected, plug into my truck and use the front landing gear. Can't do that anymore. There is power at the plug in the truck. There is power in the cord on the trailer at the 11 and 5 o'clock position, which corresponds to the 1 and 7 o'clock position in the truck plug, even with the batteries disconnected. This has me completely stumped.

 

[jnbhobe]

They do charge when hooked to shore power but will not charge while towing with the truck. There is power at the vehicle plug but it will not go into the trailer. Any suggestions?

It may be as easy as a tripped breaker in the battery compartment, look for a little reset button on the side of one of the red capped breakers. Otherwise check out the tools section on this forum.

 

[JohnDar]

Sometimes there can be enough oxidation in the plug or receptacle to prevent contact. Spraying contact cleaner on them and working the connection cleans it up. Learned that when I suddenly had no trailer brakes.

 

[NWILSON]

They do charge when hooked to shore power but will not charge while towing with the truck. There is power at the vehicle plug but it will not go into the trailer. Any suggestions?

There should also be 12V at the corresponding pin on the trailer plug. If there isn't then a breaker/fuse is probably the culprit. I don't think a diode is installed that would prevent battery voltage backfeeding to the 7pin plug.

 

[tweber]

I had the same problem, and it turned out to be a blown fuse in the truck. It happened a couple of times so I increased the amps of the fuse. That solve my issue. Good luck.

 

[hoefler]

Depending on how low your batteries are in the trailer, you may not get a good charge out of the truck. The truck is usually limited to only 30 amps, and the wire is a long run and only 10 gauge if you're lucky, or smaller. Plugging the trailer into shore power is the best way to charge your batteries.

 

[dbbls59]

I have used contact cleaner, and it is not a blown fuse in the truck because I have power at the truck plug.

 

[whp4262]

I had the same problem on my Cyclone where the battery would not charge off of the truck. One of the breakers with the red cover on the back wall of the battery compartment was bad. Mine did not have the little reset button so I had to replace it. I was able to find one at O'Reilly Auto Parts, I think camping world sells them as well. You can check all the breakers for continuity with an ohm meter just make sure you disconnect the battery, shore power and plug from the truck before you start testing.

 

[brianharrison]

The charging rate is low from the truck 7-pin connection. As mentioned, the OEM wiring is small-ish and limits current.

A simple test is to measure the trailer battery voltage after it has been unplugged from shore power for at least 30 minutes (call this resting voltage). Then connect the truck with it running, measure the voltage at the truck battery (should be near 14V), measure the voltage on the trailer battery posts. If battery voltage with connected to the truck is greater than resting voltage - you are charging. Use a digital volt ohm meter.

I have a Xantrex battery monitor that shows current in/out of the batteries; when I am first hooked up to truck after boon docking it is about +1-3 Amps charge rate while connected - I get no more than +25Ah over an 8 hour trip (if my memory serves me correct).

Hope this helps,
Brian

 

[Bob&Patty]

Remove the cover on the gang box on the pinbox. Check all the twist wire connectors......might be a loose one or one fell off. You can also see is if you have charging voltage that far when plugged into the truck. Start at the source and work your way to the batteries.

 

[wdk450]

Are you SURE that your truck's charging voltage is NOT reaching the battery? A pair voltmeter checks at the battery with first the truck disconnected from the trailer (and the trailer disconnected from shore power), then the truck connected to the trailer with the truck motor running should give you the data you need: The 2nd measurement should be higher than the first if your truck's charging current is getting to the trailer battery.

I agree with other posters that the charging current from the truck will not quickly replenish a battery. To do this right takes many hours. See the chart on this page for how much time it takes the converter/charger in your trailer to recharge the battery fully: http://www.progressivedyn.com/prod_details/charge_wizard.html
The main reason that this charging connection is there, is so that there is SOME charge in your battery for break-away emergency brake activation. I would suggest that there should be no circuit breakers or fuses in the emergency braking current path to interfere with this vital emergency braking function. I have a small, ($2 on E-Bay), self-contained voltmeter in my battery compartment to check truck charging voltage during pre-departure hook-up.

 

[JohnD]

My old 1978 Coachman Cadet 24 Travel Trailer used to blow out the trailer wiring module on my truck . . .

It is under the box of the truck near the rear bumper.

I'll bet that every one of us has one of these under the back end of our trucks . . .

I had it replaced several times . . . and finally with a better one (ie. - more expensive) and have never had the module blow out since.

Same one now working with my new 2013 Trail Runner travel trailer . . .

Old trailer . . . one battery . . . new trailer . . . two batteries!

 

[wkcox]

I recently found that a little corrosion on the negative battery post, even though to the eye it looked ok, can cause erratic testing and charging. Clean connections might be a simple fix. My camper battery was one year old and was charging from the shore power but would not power the 12 volt systems! Cleaning the connection solved the problem, but I did it after spendng a lot of time going through the block diagram trouble shooting.

 

[westxsrt10]

Disconnecting your RV's battery and using your trucks power to operate the landing gear seems wrong, this could have damaged your auto's alternators output circuits and or wiring.

 

[wdk450]

Disconnecting your RV's battery and using your trucks power to operate the landing gear seems wrong, this could have damaged your auto's alternators output circuits and or wiring.

I always use shore power for this. First thing after parking (but before unhitching), and just about last thing before pulling out is the shore power cord so that the converter/charger provides most of the current needed for the landing gear, rear stabilizers and slide hydraulic pump.

 

[evolvingpowercat]

You should be able to read the voltage accross the batteries and at the trailer connector - if wiring is good and no fuses are open then they should read the same. If they are the same then:

1. Check the grounds. There may be a poor ground connection from the trailer connector on vehicle side or trailer side, that is generating voltage drop when current flows that would impair the ability to charge batteries from the vehicle.

2. There may be a poor connection in the trailer wiring. There may be a junction box in your trailer with un-soldered wire nut spliced wires that transitons the tow vehicle cable to the trailer wiring harness, if your Heartland is built like mine. I soldered all those splices in mine to avoid issues like you are having.

Good luck.

 

[sjs731]

Re: Trailer batteries are not charging from my vehicle Followup.

I had this happen to me and it was a fuse under the hood of the truck that had blown.


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Steve and Carrie
HOC# 2252
2007 GMC 2500HD Duramax
B&W Companion Hitch
2012 Sundance 3300CK