Should truck charge camper batterys while traveling

On are first long trip in our truck camper (Lance 921) we were supprised when after ten hours of driving that our camper battery was low on charge. During the trip we had the fridge on DC and the furnace running, but outside temps were not to bad. I thought that the power from the truck would have been able to keep up with these two items. Does this seem right?

I don't know how truck in-bed campers are set-up but driving while hooked up to my TT does not recharge the trailer's battery to any degree.  I have to recharge it with a generator or plug into 110 AC somewhere to recharge it.

I would think it should charge your camper battery

On my 5th wheel the truck will charge my camper batteries. ;D

Now I could be wrong but I think on my Ford I had to have the 7 way plug wire that way on my Chevy it can that way ???

It sounds like to me that the plug for your truck is not wired right or maybe the camper plug.

When you find out let us know

Pat

If you plug in with the 7-waay, AND the charge wire s connected, it ought to charge your TC battery.  Check onliner for a pin-out to see which are which and test for power to that pin with endine running, and no connect while engine off. 

Next be sure the Lance is set up for that, might need to check with Lance on that.

My Alpenlite would as did my Arctic Fox and Coachmen.

Some trucks come wired to the plug for battery charging but there is no fuse installed in the circuit. If that is the case, go to an auto parts store and purchase the correct one and install it. I know the Chevrolet trucks at work did not have the fuse installed.

No one has mentioned that a refrigerator running on DC will require somewhere between 25 and 30 amps. Since the DC mode is not really designed for cooling, just temperature maintenance, the refrigerator is running 100% of the time.  With the furnace running you can add another 5-8 amps. This in addition to what the truck chassis is requiring the alternator to produce. This is a fairly heavy load on a "standard" alternator. If you stop and turn the engine off for even a short time, the batteries will be knocked down pretty quickly with that kind of load.

Another factor can be that the charge wire, at these amperage requirements, is not nearly heavy enough to provide the voltage necessary to charge the batteries and run the appliances. Something else to check.

Most of the newer trucks with factory towing packages are equipped with large enough wire and are fused with a 40-50 amp fuse so it should be sufficient for this purpose. If you had the plug installed by an aftermarket shop then it would definitely be worth checking the wire size and fuse.

Thanks everyone. The truck is factory wired and it is hot with the key. The camper also has a 7 pin connector with a 8 ga wire for the hot lead (I did not measure it but the truck wire is not #8 wire). I am wondering if RLSharp might be correct in that I am drawing more power than I am getting to the camper. As I stated the battery was low not dead and it is not a true deep cycle battery. For the rest of the trip I ran the fridge on LP and it seemed much better.

RLSharp said:

Another factor can be that the charge wire, at these amperage requirements, is not nearly heavy enough to provide the voltage necessary to charge the batteries and run the appliances. Something else to check.

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The wire between the truck engine compartment, all the way back to the trailer battery, is almost always of insufficient size to effectively keep the trailer battery charged if you are drawing any kind of a load in the trailer. This wire is usually 12 gage or smaller, and the total length is probably close to 30 feet in a lot of cases. the voltage drop across this length, even at a 10 amp draw, is enough so that the trailer battery will become discharged. It requires AT LEAST 13 volts to fully charge a battery, and with only a 2 volt drop you only will have 11.6 volts available at the end of the wire, assuming a typical 13.6 volt output from the truck alternator.


The solution is to rewire using at least a 10 gage wire, preferably 8 gage. This is not easy to do, but it is the only way to assure full charging of the trailer battery when you are drawing heavy loads while travelling.

huronwoods said:

The solution is to rewire using at least a 10 gage wire, preferably 8 gage. This is not easy to do, but it is the only way to assure full charging of the trailer battery when you are drawing heavy loads while travelling.

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Or just run on propane. That way you don't have to remember to immediately turn the refrigerator off when you turn the truck engine off. You do have to remember to shut the refrigerator off when fueling.

huronwoods said:

The wire between the truck engine compartment, all the way back to the trailer battery, is almost always of insufficient size to effectively keep the trailer battery charged if you are drawing any kind of a load in the trailer. This wire is usually 12 gage or smaller, and the total length is probably close to 30 feet in a lot of cases. the voltage drop across this length, even at a 10 amp draw, is enough so that the trailer battery will become discharged. It requires AT LEAST 13 volts to fully charge a battery, and with only a 2 volt drop you only will have 11.6 volts available at the end of the wire, assuming a typical 13.6 volt output from the truck alternator.


The solution is to rewire using at least a 10 gage wire, preferably 8 gage. This is not easy to do, but it is the only way to assure full charging of the trailer battery when you are drawing heavy loads while travelling.

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Years ago we were in a Caravan to New England with Bill Farlow, he was a tech guru for Trailer Life at the time, and he recommended at least 8 gage wire for both the charging circuit and the brakes.  It takes 2 wires the whole way, the + and the - to ensure that the connection and current carrying capacity is there.  A lot of work and some expense.  Also, I would add, use good connectors, not the cheap automobile ones but something like Anderson Power Poles or other high current rated ones.

webefine said:

On are first long trip in our truck camper (Lance 921) we were supprised when after ten hours of driving that our camper battery was low on charge. During the trip we had the fridge on DC and the furnace running, but outside temps were not to bad. I thought that the power from the truck would have been able to keep up with these two items. Does this seem right?

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Only if your camper and truck are so wired.  From the Lance Campers website:

"When you're on the road, the truck alternator (if dealer wired) distributes power to both the truck battery and the camper battery ? provided you've installed a battery in the battery compartment in your camper and have the camper cable plugged into the socket in the bed of your truck. The camper battery operates all of the 12-volt appliances when the camper isn't plugged into a 110-volt source."  [emphasis mine]

http://www.lancecamper.com/ownersupport/camperpower.html

So if you have a connector wired in on your truck and a the mating connector wired on the camper, and you have plugged them in, then you should have power from your alternator.    That does depend on the capacity of your truck alternator having the capacity for this purpose.  A heavy duty alternator may be needed.    Find yourself a Lance dealer or shop that can do the wiring needed.

Meanwhile you can do two things.

1.  Consider doubling up on your battery, if your camper will permit it. 
2.  Even if you double up, quit using your fridge set on DC.  DC operation will chew up a battery fast.  Propane operation is what most of us use on the road
with no problems.  Just remember to turn off the fridge at its control board so the ignitor will not spark during refueling.

1.  Consider doubling up on your battery, if your camper will permit it.

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Can someone please post a link or lend instructions as to how to do this modification- I am sure I am going to need to do this as I will rarely camp with hookups. How can I find out if my TC will allow this?  2006 Bigfoot 9.5FS

Here's an article in our library on Adding batteries to your RV.  *