Camper Battery doesnt charge while going down the road

[desertratt1]

Just curious why my house battery would not charge while driving. I have 2001 Dodge Cummins. Anyone know anything about this and is there a way to have it charging. I just assumed it would charge thru the 7 pin. Also we had check light on our frig i ordered a new dinosaur board put it in didnt change a thing. Would only give check light while driving down the road we constantly have to recent frig would be fine than do it again.

Appreciate any input.

Thanks

[harley4275]

My friend had the same problem with his living light camper. Turned out there's a fuse between the battery and the panel that was hidden behind the water heater. Once you replace the fuse everything work for perfect

[theoldwizard1]

ScottG wrote:

The OP's truck stays in the 14.X range.

"I'm from MO, show me !"

What matters is the voltage AT THE HOUSE BATTERY BANK while the vehicle is during down the road !

Dollars to donuts, it is <13.5V !

[theoldwizard1]

cewillis wrote:

theoldwizard1 wrote:

Much simpler and probably more effective is a DC-DC charger.

Modern vehicles vehicles drop the voltage from the alternator to <13.5V shortly after starting. This has is not adequate to charge a house battery. The DC-DC charger boosts that up to the proper charging voltage.

Adequate current transfer is still required in any case -- thus heavy gauge wire.

Having a big, fat wire does not do any good when the voltage coming out of the alternator is <13.5V !

cewillis wrote:
My alternator - and I suspect all functioning alternators - charges at a voltage determined by the load voltage. While the load voltage is below ~14.3 to 14.4v, the alternator charges at ~14.4 volts.

Sorry, that is no longer correct. The PCM now controls the charging voltage based on various different algorithms, not just voltage. This has been the case for all major manufacturers for well over 10 years.

[covered_wagon]

need to do like me and just go from the truck batteries direct to the camper batteries thru the 7 pin you added on the truck. Only it's better to go thru a continious heavy duty relay with the trigger wire switched in the cab. this way if the camper batts are deeply discharged you won't hammer the alternator while using the intake heater or the seat heaters at the same time. Give them a chance to go, replenish the truck batts and then switch on the charge wire to the camper. The second gen alternator is just a hair shy of giving enough amps so it's best to control it and alternate the load put on it.

Just one burned diode in the alternator builds additional A/C ripple thru the system which is bad for the ECM and the PCM circuits so you want to keep the AC ripple below .05 that will tell you if your alt is still good. It can still chrge with a burned diode but the A/C noise hurts the electronics over time.

[stevenal]

Yes. The pin directly across from the hot one should be ground, and should connect to the truck's metal frame. Please see my previous question.

[desertratt1]

First thank you to everyone that chimed in on this also the references to websites. So i checked the seven pin on my truck i have power top right pin. I than checked the cord between the truck and camper no power.I than went got another cord that plugs into 7 pin on truck to the cord on the camper and i had power same pin top right. I than plugged that into the camper pulled out the battery which was still hooked up to the camper and started my truck i get nothing to the battery. i Checked the voltage before i started truck and after and no change so it is not being charged at all. All fuses in the fuse panel are good. So could this be a grounding issue?

Thanks

Rick

[stevenal]

covered wagon wrote:

stevenal wrote:
Where is the receptacle? In the bed, or are you using the OEM trailer connector near the truck's rear bumper.

Im using the trailer connecter near the hitch for the outside lights. then runs toward the front left corner for the camper cord to plug in there to an added recipicle and then to the camper to plug in the camper recepticle. I forgot too, being unfair to everyone here...that my charge wire is coming from the truck batteries (separate) to the forward umbilical cord recepticle. But a huge troublsome problem exists in the wire connections behind the camper factory recepticle. They leave plenty of slack and wire to pull it out and check those connections. Like said before, twice I've seen where they relied on tightening the screw to go thru the wire insulation and not properly stripping the wire. It was amazing to find that also on my new NL camper.

I was asking the OP.

[covered_wagon]

mkirsch wrote:

ScottG wrote:
Many posts here do not apply to your 2002 Dodge and others are just wrong in their assumptions and understandings of the charge system.
Proceed carefully.

So, what does apply, and what does not?

You can't just throw this statement out there and not back it up.

Scott picked up on the fact that I am running a seperate charge wire thru a relay controlled by a switch on the dash. Thanks to his statement... I realized I had failed to remember that. I'm also running a number 8 tinned wire which further modifies it from the factory camper special trailer recepticle charge wire.

[covered_wagon]

stevenal wrote:
Where is the receptacle? In the bed, or are you using the OEM trailer connector near the truck's rear bumper.

Im using the trailer connecter near the hitch for the outside lights. then runs toward the front left corner for the camper cord to plug in there to an added recipicle and then to the camper to plug in the camper recepticle. I forgot too, being unfair to everyone here...that my charge wire is coming from the truck batteries (separate) to the forward umbilical cord recepticle. But a huge troublsome problem exists in the wire connections behind the camper factory recepticle. They leave plenty of slack and wire to pull it out and check those connections. Like said before, twice I've seen where they relied on tightening the screw to go thru the wire insulation and not properly stripping the wire. It was amazing to find that also on my new NL camper.

[mkirsch]

ScottG wrote:
Many posts here do not apply to your 2002 Dodge and others are just wrong in their assumptions and understandings of the charge system.
Proceed carefully.

So, what does apply, and what does not?

You can't just throw this statement out there and not back it up.

[ScottG]

Many posts here do not apply to your 2002 Dodge and others are just wrong in their assumptions and understandings of the charge system.
Proceed carefully.

[adamis]

Others with more knowledge will likely chime in but here is my two cents... The wire gauge is critical but isn't as critical as some make it out to be. You can pull 30 amps of current from a 22 gauge wire, the question is how long that wire will last before it melts. Also, the voltage is also critical but is not going to define how well your camper charges off the alternator. It is the combination of these two elements that is critical.

Here's the thing, current flows where there is a difference in voltage. Your truck alternator might keep the truck at around 13.3 volts. If your camper battery is at say 12.6 volts you only have .7 volts of potential difference. That's just not going to flow a lot of power from one battery to the other.

This as others have said is where DC to DC chargers earn their keep. There is plenty of amperage that can be pulled from the truck but you need a special circuit that will pull this at a higher current and then use that current to create a higher voltage to the camper battery and thus force more current into it.

There is nothing wrong with upgrading the wiring from the truck, it is the first good step to take. But don't make the mistake and think that upgrading the wire is going to solve your charging woes. You need to invest in a DC to DC charger if you want to be able to get good results charging the camper battery from the truck. And, before the naysayers say "I have never needed a DC to DC charger, my camper charges just fine"... Yes, it will work and for some can work fine in many situations, but it won't be the most effective for situations where you need a lot of power for your camper.

[stevenal]

Where is the receptacle? In the bed, or are you using the OEM trailer connector near the truck's rear bumper.

[Grit_dog]

covered wagon wrote:

desertratt1 wrote:
I thank everyone for all the impute. Looks like i need to do some checking. I looked under the hood pulled the fuse/relay cover i have a trailer relay. Not sure how all that works. Camper is off truck i will hook it up start checking things out. I just assumed the truck would charge the battery period. My Dodge is a camper special. I plan on installing a 200 watt solar setup at some point but i considered the truck charging the battery in the camper a given. Like i said will look at all the suggestions to resolve this over weekend. Than will get back and post.

Thanks
Rick

My 02 is a camper special as well. I have my continious duty relay switched so I can let the alternater replenish the starting batts from using the starter, grid heaters and finally seat heaters. Once warmed up and time allowed to charge the truck batts, I switch that on to take care of the two camper batteries. 5 hrs run time brings it up to near full charge on 2 deep cycle 12 volt batts. It works great and run furnace whenever I need, sometimes all night.

That was a good suggestion to make sure your fridge is not set to run 12 volts. I never use the automated setting.

So you switch on the fly and let the truck run "on batteries only" for a while, while sending all the alternator power to the camper batteries?
That is very interesting and outwardly sounds ingenious. Not sure how it would integrate with vehicle systems that monitor SOC of the vehicle start batteries. Pretty cool though!