Battery charging from tow vehicle - Montana Owners Club

patodonn · 08-23-2005, 07:06 PM

Just in general, from experience, how long do you need to run the tow vehicle engine daily (or every other day) while hooked up to keep the RV batteries adequately charged while boon-docking? I have heard a figure of about 45 min each morning. We are thinking of about 5-7 days duration.

Probably no furnace use planned. We might use the TV / computer for an hour or so through a small inverter, maybe every other day. Other than that, lights, fridge, water pump, propane sniffer and the flashlight charger. Got to keep a good enough charge to get the slides in and the front struts retracted when it is time to leave. We could be hooked up, motor running, to help with that. Did I forget anything??

Thanks,

HamRad · 08-24-2005, 08:40 AM

Hi PJ,
Gosh PJ.... I don't know. I know I ran my batteries down shortly after I got the rig. I tried charging them up by running the engine and it did not work. I was about an hour from home. I tried running the engine for about 30 minutes and still did not get enough to even pull the slides in. Even after driving home for over and hour the batteries were still not charged. You actually only get a relatively small trickle type charge from what I was told. Probably best to invest in a small generator. The friends we were with had a small Honda generator. Hooked that up and got the slides in with no problem.

I'd think a 500 watt or 1000 watt unit would take care of what you're talking about. We opted for the Honda 2000eui and have been VERY happy with it.

Good luck.

Dennis and Mary Kay

Montana_2785 · 08-24-2005, 08:58 AM

The amount of current and voltage drop you will get through the normal trailer umbilical doesn't make for good charging. If you are out in the boonies, you might try connecting your TV to the battery using jumper cables. Those will support a higher current with less voltage drop.

If you do this more than once in a great while, I would agree that a small generator would be in order...

Eric

patodonn · 08-24-2005, 06:03 PM

OK...thanks y'all....I was just wondering. No plans to boon-dock, but you never know. Maybe two or three consecutive nights on the road an various Wal-mart / other "no hookup" locations. There are several military CGs where you have to boon-dock three or four days while waiting for a hookup.

I just don't want to get a generator...one more thing to haul around that I use only now and then. Keeping Mr. Monty below max wt is an ongoing struggle.

Thanks,

dannyl · 08-25-2005, 09:59 AM

A better use of money than a generator would be a battery charger to use when you could plug in for awhile. Since the TV doesn't do much more than trickle charge spending 30 minutes or so in a rest area with a plug would help.
I plan on using mine alot in areas with no juice so will keep my charger handy when I pull out.

sreigle · 08-26-2005, 08:55 PM

Dennis, I wonder if you have a blown fuse in your truck that's keeping it from feeding 12v to the Montana? I know that happens. I'm not sure where that fuse is located.

When we recently had the battery problem we had zero 12v to retract the landing gear. Nkwist suggested firing up the truck engine with umbilical attached. We did and immediately were able to retract the landing gear. On that trip we tried using the water pump during potty stops. No dice without battery. Fired up the truck and we had 12v to run the pump.

Yours may not have charged the battery if that fuse is blown.

Charlie · 08-27-2005, 06:00 AM

On my truck there is a fuse box under the hood on the driver's side. The day I picked up the Monty I did not have a brake light on the left side on the trailer. TV lights were working fine. After some checking the tech found a blown fuse. He explained it to me that the 7-pin connector has a seperate set of fuses, I did not know this, thought that all brake and tail lights truck and trailer were on the same circuit. What caused the fuse to blow was a short in a boat trailer when I used the 7 pin connector.

sreigle · 08-28-2005, 08:56 AM

Good info, thanks, Charlie. I did not know that, either.

HamRad · 08-28-2005, 09:29 PM

Hi Steve,
No. No blown fuse. I was getting a charge but it is just a trickle charge. If I'd had to drive 4 or 5 hours then I'm sure the battery would have come back to near full charge. But it will not or can not charge a completely depleted battery in a short time. Under normal circumstances it works fine.

Dennis

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