Batter and charging system

A single 100W solar panel and small solar charge controller would eliminate a lot of work and worry. You do have to be parked in the sun, however.

I'd assume that you know that the trailer probably has some parasitic loads that are powered when the trailer is in storage. Those parasitic loads will drain a typical battery within a week or so. The solution is to have a disconnect switch near the battery or unclamp one cable from the battery.

Typical charge from a truck's alternator through a trailer umbilical plug will be a few amps (2A-> 10A). It will take a long time to charge a depleted battery at those low rates. Battery cables connecting the truck's battery to the trailer battery will be faster but the last few amps needed for a full charge will still need a long time to charge the trailer battery, fully.

If you have a separate battery charger, I'd suggest to take the battery to the charger and put a full charge into it. If your charger will supply 16V, you'll be able to "Equalize" charge the battery and that will be great maintenance, stirring the electrolyte and eliminate any stratification.

I believe the comment about charging through the 7 pin connector is correct. It provides a low level charge while driving.

When we camp without electricity, I use a set of jumper cables and re-charge my battery in about 20 minutes.

Obviously we do not camp with electric power very often or I would have to find a better way.

Wow!
Great ideas all!

I think I'll just take that battery home every once in awhile and put it on a charger. Maybe get a 2nd battery and swap 'em.

There is a 7pin female in the bed of the truck.
If I hook that up directly to a deep cycle would it charge over time?
It would certainly be getting higher amps at highway speeds than at idle.

Thanks again.
B

eHoefler wrote:
There is no way the truck, especialy at idle, will keep up with the demand of the furnace and lights, let alone charge the battery. The most you will ever get out of the truck is 30 amps, with the length of run and voltage drop, you'll be lucky to get 20-25 amps at the plug. It is not so much a charge line, but a keep alive line.

My experience (as measured with a DC Amp meter) is that my truck will only charge about about 2-3 amps with the OEM sized wiring.

If I remember correctly, up through 2015, GM trucks aren't wired by default to charge - the charge line isn't connected under the hood. The wire is there, but not connected to the aux power terminal, nor is a fuse in place that powers that terminal (post)

There is no way the truck, especialy at idle, will keep up with the demand of the furnace and lights, let alone charge the battery. The most you will ever get out of the truck is 30 amps, with the length of run and voltage drop, you'll be lucky to get 20-25 amps at the plug. It is not so much a charge line, but a keep alive line.

even if the truck and the trailer are set up with a batt + wire, this doesnt mean either plug has been wired with them so that they can be connected.

and even when they are connected, very few amps can make it to the trailer battery, so it will take a very looong time to charge the battery that way.

Im assuming you have a dual purpose 12v battery in the trailer, and these will supply voltage but when they run out of juice they die quickly.... and when they are dead, it takes a LOT of juice to get them back to full charge.

the onboard multistage charger will deliver more amps to the battery and controlled better so that the battery charges as fast as physically possible.... where the truck can only give it a single stage trickle charge thru its batt+ wire and alternator system....

you are correct that the trailer battery may need to be replaced, but still, if you are attempting to charge it only from the truck, a new battery will soon go bad because of the extremely inefficient charging that the battery is constantly being abused with...

a good charging system, and true deep cycle batteries installed, being used PROPERLY, should last a minimum of 6 years with an expected life of 8+ years.

with the truck running and all switches off, you should find a batt hot wire at the trailer plug receptical on the bumper... if not, you may have a blown fuse in the truck.. or maybe it was never connected.

if you DO have a hot wire at the trailer plug, connect a multimeter to the battery and see the voltage.... when you plug the trailer in the voltage should increase at least 1 volt immediately. if not wait a couple minutes to see if the voltage at the trailer battery increases... if no increase, you have a wiring issue in the trailer circuit..... either at the plug (most likely), or elsewhere in the harness. the second most likely place would be where the batt+ wire from the harness connects to the trailer... fuse panel?

The running lights have nothing to do with interior power. They are an extension of your truck lights. I don’t think your truck will keep battery charged at idle. My guess is you used up all your stored power and your battery is dead.

You could use a test light or 12V meter. Look at a diagram of the 7 way connector , "+" should be 12V chg. pin. Thats where the trailer battery gets its charge from.


google 'pics of a 7 way trailer plug'

Test that pin with the ignition on .

IF ALL ELSE FAILS...use jumper cables from the TV battery to TT battery.