Trailer battery not charging while towing???

[ghamr]

Looses charge if refer on battery for a few hours when driving. New battery (2014), 2012 Bambi, battery recharges when on shore power. Ideas....

[acstokes]

Have you checked your umbilical cord's 7-wire connector to be sure the terminals are clean and not corroded?

[dznf0g]

How much does the refer draw? The umbilical doesn't supply a lot of power. I checked mine with the Trimetric monitor and my particular truck only supplies 10 available excess amps over and above any other loads that are operating while under way. It supplies a total of 13 amps but other stuff is on, like refer board, propane detector, etc.

If the refer heating element draws more than 10 amps,(which I'm sure it does) you are operating at a deficit

[acstokes]

The heating element only works when you're plugged in shore power. Normally when traveling you'll be on propane when the refers on.

[dznf0g]

I was assuming OP has a 3 way and is running on 12V cooling??? Maybe not??

[acstokes]

I was assuming OP has a 3 way and is running on 12V cooling??? Maybe not??

I thought that too, but I noticed he has a 2007 model and I don't think 12v was an option then.

[dznf0g]

If it's a 2 way, I can't fathom why the refer would draw the batt down. I guess we need to know if he has a draw down ONLY when the refer is on. The refer draws very little amperage when on propane....like milliamps

[acstokes]

If it's a 2 way, I can't fathom why the refer would draw the batt down. I guess we need to know if he has a draw down ONLY when the refer is on. The refer draws very little amperage when on propane....like milliamps

I think it's something other than the refer drawing the battery down.

[acstokes]

but I noticed he has a 2007 model and I don't think 12v was an option then.

My apologies. The OP has a 2012, not 2007. For all I know he does have a 3-way refer w/12v power.

[daveswenson]

Originally Posted by acstokes

My apologies. The OP has a 2012, not 2007. For all I know he does have a 3-way refer w/12v power.

My 2012 is a two way.

[idroba]

I doubt that the poster has a 3 way refrigerator, so the current draw should be in the range of 0.3 to 0.5 amps (when the fan is on, I think the sport 22 has a fan). At any rate not enough to draw the battery down that fast, unless it is virtually discharged anyway.

Test the tow vehicle plug for 12 volts available to charge. It may not be hooked up or something may be wrong with it.

If it is a new battery, it should not discharge in a few hours, especially while driving. You could have a defective battery, even if it is new.

[idroba]

Second thought: on shore power, are you putting the use/store switch in USE. That is the only way it will charge when plugged into grid power. In other words, are you sure you are starting with a charged battery?

[ghamr]

To all for prompt response: Refer is 3 way & we would only use the batt mode while towing (propane flames out due to wind). We are fairly sure that we have
used the batt mode w/o discharging the batt while towing...this issue just started a couple of weeks ago on our way back to the lower 48 from AK.
I have used contact cleaner on the 7 wire. Is there another way to clean the contacts? I think the answer maybe that we are running a deficit which when the battery was new it could overcome. The Dometic refer specs are 12 V/11 amps. I am (usually) handy...

[Bill M.]

Do not know what it takes to run a 12 ref. I do know that I ran my batteries down to 12.2 v and then pulled the trailer for 6 hours. At the end they were still 12.2 volts. Only thing running was propane refig. and I used the water pump for 15 seconds at one stop. the TV just does not put much charge back on the batteries.

[acstokes]

Assuming the 7-wire connector is making contact and assuming no other large loads on the circuit such as lights on, etc., the only other possibility is your batteries are losing their capacity. Meaning, even though they show a full charge when you start out they can't sustain that kind of load for long periods. 11 amps is a significant load and is also more than your tow vehicle will deliver without a heavy duty alternator. Even though you likely have deep cycle batteries, you're probably depleting them in excess of 50% each time you travel. It's takes more than a truck alternator and an hour or two of recharging for the batteries to recover from that state of depletion and they've probably become sulfated.

You need to either not run the refer when traveling or fix it so that propane doesn't blow out.

[SafariBez]

Not sure if this is relevant. But my brother's 2011 F150 came from the factory missing a fuse that was needed to charge the Airstream batteries while going down the road. Easy fix once discovered, but it took us a while.

[ghamr]

So, should I run the frig on LP while driving & if the flame blows out the ignitor will restart it when I stop? Will the ignitor keep sparking if there is too much airflow thru the vents and maybe run the batt down? I think my best option is to start with a cold refer run on LP or shore power, then stop for lunch & turn on the LP to cool it down. I'm not sure why there is a batt mode on the refer!

[Skater]

Originally Posted by acstokes

11 amps is a significant load and is also more than your tow vehicle will deliver without a heavy duty alternator.

That, and the wiring from the truck to the trailer usually can't support a huge draw.

Originally Posted by ghamr

So, should I run the frig on LP while driving & if the flame blows out the ignitor will restart it when I stop? Will the ignitor keep sparking if there is too much airflow thru the vents and maybe run the batt down? I think my best option is to start with a cold refer run on LP or shore power, then stop for lunch & turn on the LP to cool it down. I'm not sure why there is a batt mode on the refer!

What kind of wind are we talking about here? It shouldn't be blowing out under normal circumstances. It makes me wonder if the flame isn't adjusted correctly, or spiders are in the venturi or whatever, or something like that.

[idroba]

On Propane, if the flame does not ignite or blows out, in general there is a limited window of time for the automatic re light to operate, like maybe twice or three times, then it simply shuts down. It must then be turned off to reset it.

The spark lighting system takes very little power to operate, BTW.

I would look for the reason the propane flame goes out, and eliminate any use of 12 volt power for the heater. I am surprised your unit has a 3 way refrigerator to begin with. My 2014 20' FC does not.

[bovk]

The 7-way plug is not the only suspect. The cable from it goes to a junction box inside of the AS. IF YOU HAVE A PROBLEM WITH LIGHTS, CHARGING OR BRAKES CHECK THE CONNECTIONS IN THIS BOX!
Sorry for capital letters, i just finished crawling there in 95 degF weather and tighten the connections. All inside of the box were so loose I think they were like this from the factory.