Community Forums

Chillbilly · 03-06-2015, 06:06 PM

Ok, here goes. I parked my 5th wheel in a remote area where there is no AC available. Now the trailer battery is dead. When I hook it up to the truck to move it, will I be able to raise the legs? There is no way to charge the trailer battery, and no jumper cables are available.

PushedAround · 03-06-2015, 06:14 PM

Unless the 7 pin plug carries 12v to keep the trailer battery topped up during towing, then no, it won't work. If your truck battery is good, just pull it out and use it to raise the legs. That should not drain it down much. Of course if it's not.....

J Birder · 03-06-2015, 06:21 PM

The 7 pin plug should be wired in such a way that the truck will charge the trailer battery. However, on many (all?) trucks, the connection to do that is not enabled when the truck comes from the factory. To enable it, you may need to add an additional fuse in the truck.s fuse panel.

Joel

mhs4771 · 03-06-2015, 06:33 PM

Even if you do have the charge line from the TV to the RV, it may not be able to carry the current required to run the landing gear, you can only find out by trying, or find someone you can borrow a battery from.

Cummins12V98 · 03-06-2015, 07:06 PM

Bring a battery.

suiteowner · 03-06-2015, 07:36 PM

Take one of the batteries out of the truck put it in the trailer raise the trailer remove the battery and put it back in the truck...DON'T SHUTDOWN THE TRUCK ENGINE...

suiteowner · 03-06-2015, 07:40 PM

Quote:

Originally Posted by suiteowner

Take one of the batteries out of the truck put it in the trailer raise the trailer remove the battery and put it back in the truck...DON'T SHUTDOWN THE TRUCK ENGINE...

One more thing when removing the battery negative cable first off and last on when you put it back in the truck...

wa8yxm · 03-06-2015, 07:52 PM

Short answer is no,, Long answer is perhaps after an hour of being connected engine running.

Better answer is QuickCable Rescue Jump Pack 900 - Free Shipping: BatteryMart.com

This type of device, Hook it AFTER the disconnect solenoid (Assuming the jacks are after the solenoid, otherwise hook up befor it) and disconnect so it's not trying to charge the house batteries, then bring the jacks up and away to the nearest shore power.

wingnut60 · 03-06-2015, 08:33 PM

If you can't get enough power, get 2 bottle jacks and some wood blocks--jack the trailer up enough to get under it. You are still going to have a problem with the legs extended to travel if you can't charge the battery.
Joe

nothermark · 03-06-2015, 09:29 PM

Assuming you have already screwed up and done that I would say a trip to somewhere to get jumper cables is in order. If you jump the trailer battery to the truck battery while the engine is running there should be a quick charge to the house battery to a reasonable fraction of it's capacity. I'd let it run that way for 10 minutes or so then disconnect the cables and hook up without shutting the engine down. If enough charge transferred over you should be able to raise the jacks. Assuming the drive home is hours not minutes the engine battery will charge on the way.

FWIW the theory is that the two batteries will try to equalize charges between them. If they were the same size, one was full and one was flat then they would go to 50% charge each. They probably are not the same size and the low battery is probably not at zero so the proportion of charge to moved will depend on the ratio of capacities and levels of charge in each battery. If the house battery is 2x the capacity of the truck battery the charge would equalize at roughly 1/3 capacity for each battery after the charging current goes to 0 because the voltages equalize. Then the alternator will add to the mix.

If the difference between the batteries is high the initial equalizing current can be high as it will be limited by the voltage difference and the resistance of the jumper cables and the resistance of the batteries. In other words low resistances so high current decreasing as the voltage differential goes to zero. That could be a good reason to avoid cheap cables. ;-)

Arch Hoagland · 03-06-2015, 09:49 PM

I never had a fifth wheel but I would think there'd be a hand crank of some sort.

It looks like that's not the case from the replies I've read so far.

Chillbilly · 03-07-2015, 07:17 AM

Guess I'll have to buy a spare battery.

Timay · 03-07-2015, 09:11 AM

As Arch says, my 5er has a hand crank for both the landing gear and the slides. Yours should, too.

Tim

JethroHeller · 03-07-2015, 09:18 AM

There is a hand crank but you'll be there a month using it, my truck supplies power just fine when trailer battery is dead. Just unhook you're trailer battery and test it if you're concerned about future problems.