A battery learning experience - Montana Owners Club

DonandBonnie · 11-13-2013, 12:29 AM

We recently had our first experience attempting to overnight at Wally World. We parked, dropped the front jacks for stability, ran out the slides and turned on some lights. The lights were dimmer than usual, but we thought that was because we were running on battery power only. Within five minutes the lights dimmed even more, so we decided to fire up the built in generator. We got one groan out of the generator and nothing more. Dead battery! By this time we were sitting in darkness. We started the truck figuring that we could charge up the battery. After a half hour we could only get a dim glow when we turned on an inside light. Not wanting to leave the truck run all night we called our son, two hours away, and asked if he would be willing to bring over his portable generator to jump the Big Sky so we could start our own generator. Having done that our generator ran for the rest of the night with no further incident.

The next day we had our electrical system checked out. The result was simple. We asked the battery to do more than it was designed to do and we drained it. The single battery that came with the Big Sky could provide enough power to start the generator and not much more. There was additional room in the battery compartment, so we chose to add two additional batteries. I'm sure that's overkill, but now with three batteries we have enough power to do what we need to do to set up and start the generator.

Phil P · 11-13-2013, 12:45 AM

Hi

Something else you may check.

The Chevrolet trucks are delivered with the 12 v house power lead to the trailer connector disconnected. The new owner has to request the dealer to hook it up.

I don’t know anything about the Ford trucks but you should have been able to operate your lights from the Ford batteries.

Last but not least I carry a set of the longest heavy duty jumper cables that I can find in the trailer. I used them once to retract the slides when our battery went bad. The battery normally will support the trailer for one night but that time it didn’t. I replaced the battery with the same make and type and haven’t had any further problems.

Phil P

steves · 11-13-2013, 12:58 AM

Agree with Phil P. Your single battery should have handled your lighting needs. Check your trucks plug/fuse to see if you are getting a charge to your rig.

DonandBonnie · 11-13-2013, 01:38 AM

I think my main problem was from overuse of the battery before using the lights. I drove all day with the refrigerator running, then ran out the slides and jacks. Turning on the lights was the final straw to kill an already drained battery. The lights did come back when I plugged in the truck and the battery did start to charge, but it was drained so low that it would have taken hours to come back. Jumper cables are on my list of must have things to buy.

bncinwv · 11-13-2013, 01:47 AM

Quote:

quote:Originally posted by DonandBonnie

Jumper cables are on my list of must have things to buy.

Hind-sight is 20/20, but weren't you in the parking lot of a Wal-Mart? If it was a 24 hour one, seems like the simple solution would have been to purchase a set of jumper cables and use them to start the generator via a jump from the truck? The multiple batteries are a necessity in my view. We have to run the fridge overnight at the mini-storage before departing and a single battery configuration has not worked for us at all.
Bingo

DonandBonnie · 11-13-2013, 01:56 AM

Bingo, Obviously you have mistaken me for someone who can think on his feet.

bncinwv · 11-13-2013, 02:11 AM

About like one trip we were making and I thought the battery was dead, stopped at a Walmart in the wee hours of the morning, bought a battery, and the brand-new battery wouldn't work either?? It helps when the battery disconnect is not turned on!!! Returned battery, replaced the existing one, turned battery disconnect off, and went upon my merry, embarassed way!!!

Bingo

**DQDick** · 11-13-2013, 03:49 AM

Bingo, you're not the only one of us who has an embarrassing battery disconnect story. We currently have two deep cycle batteries and there plenty good for an overnight stay at Wally World. What we do for a backup is that I carry one of the jump start batteries in the truck. That way I can jump the truck if need be or can jump the Monty and close the slides. Haven't had to jump the truck yet, but have had to jump the Monty due to operator error.

Flymutt · 11-13-2013, 04:12 AM

Quote:

quote:Originally posted by DonandBonnie

There was additional room in the battery compartment, so we chose to add two additional batteries.

Were you able to vent all three batteries? Sorry...first thought that popped into my head

mhs4771 · 11-13-2013, 04:47 AM

With a good set of jumper cables should have been able to jumper from the TV battery to get the genny started.

Art-n-Marge · 11-13-2013, 07:41 AM

If you ran the fridge all day while driving, the battery should have stayed charged since the truck would be recharging the battery via the properly wired hitch wiring. Your Ford does not have the Chevy/GMC fuse issue and the truck should have been recharging the single battery.

While I'm surprised your Big Sky came with only one battery this all still should have worked for what you did. Operating the slides and landing legs should NOT have drained your battery enough not be able to start the generator. I guess next time if you are mostly level, then start the generator first, THEN operate the the slides and legs. Or keep the rig connected to the TV and the Ford running to provide some extra juice.

I'm guessing you should still check the TV connector to ensure you are getting 12v out of it and the battery is getting recharged while connected. It's pin 4 in the 7 pin wiring (pin 4 on the truck is opposite pin 4 on the trailer end). If you need help with this please ask.

H. John Kohl · 11-13-2013, 09:13 AM

Quote:

quote:Originally posted by DonandBonnie
-snip-

The next day we had our electrical system checked out. The result was simple. We asked the battery to do more than it was designed to do and we drained it. The single battery that came with the Big Sky could provide enough power to start the generator and not much more. There was additional room in the battery compartment, so we chose to add two additional batteries. I'm sure that's overkill, but now with three batteries we have enough power to do what we need to do to set up and start the generator.

Don and Bonnie,
I agree your battery should have survived the usage you described. The refrigerator only uses the 12vdc for the circuit board control and the propane for providing the heat exchange function of these refrigerators.

You mentioned putting more in. I would be suspicious of the original battery being bad and recommend having it checked with a load test. If it is bad it will take the new batteries down with it and drain them a lot faster than expected.

If you have three batteries I would consider running the rv on two batteries and isolating the third one for just starting the generator. You can put a recarging diode system used by fisherman to charge their trolling batteries. It will keep the generator battery charged yet prevent if from providing power to the charging system/other batteries and is always ready to start the generator. Just my thoughts.

Good luck and safe travels.

Overlord · 11-13-2013, 10:54 AM

There is a 12 volt power source on your 7 pin. In standard configuration, it is only hot with the key on, but the fuse and relay that are necessary to energize the circuit must be in place for it to work.

The trucks are delivered without them installed. If you bought the truck new, there should have been a plastic bag in the driver door pocket containing a fuse and a relay. They have to be installed in the fuse and relay box to power the 7 pin plug. Look at the diagram under box cover for correlating fuse and relay positions. If the spots are empty, you will have to install them.

If you do not have the necessary fuse and/or relay, check with your local Ford dealership for what is needed, but you can most likely pick them up at a auto parts store for a lot cheaper.

If you want constant power (with the key off) you can remove the relay and put a short jumper in its place, you still must have the fuse in place.

DonandBonnie · 11-13-2013, 11:04 AM

Thanks all for the input. I'm not quite sure what to say about the charging circuit. I took the truck and trailer to a mechanic that I've dealt with for several years. He works on both vehicles and RV's and trailers. I've never had cause to dispute his work. He checked the truck circuit first and pronounced it ok. By the time I got to him, the generator had been running for several hours and the battery was fully charged. He unhooked the battery and put his meters on it and said that he saw no unusual drain. I guess he could have missed something, so I'm going to have everything rechecked. I have an appointment next week to have a one year checkup on the Big Sky at the dealer I bought it from.

There was sufficient room in the battery well of the trailer for all three to fit without modification. All three are in proper battery boxes and all three are properly vented. Flymutt thanks for the concern. John, I like your idea. I'm going to work to get that done.

H. John Kohl · 11-13-2013, 11:19 AM

Don,
If you really want to know what is happening with your batteries I suggest you look at the Bogart Trimetric 2525. Once your battery is fully charged and it is programmed it will tell you your battery usage and charge/functioning status. I have one now since I do boondocking. If you go with more than one battery I feel you would like to know its true status similar to how full are your holding tanks.

Safe travel.

DonandBonnie · 11-13-2013, 11:25 AM

John, Where do you mount the readout? We haven't boondocked much in the year that we've been full timing, but I can see that changing in the near future as we hopefully work our way through the west next year.

H. John Kohl · 11-13-2013, 12:11 PM

Don,
There are two version of Bogart displays for the 2025. RV model is an outlet box that mounts on the wall with about a 1 inch box and the meter mounts on the lip. The non rv model is flush mount. I did not know this at the time or would have gone with the flush mount. So first you have to determine where you want to mount it.
Mine is on the wall just before going up stairs into the bedroom. I like the flush mount look better if you can install it that way. It does have a non LED light mode where no information is displayed. I bring this up if you mount it where it could be viewed from the bed room. In the off mode it will not be flashing disturbing anyone trying to sleep. I do want mine in a place where it can be easily viewed multiple times.

I hope this helps.

CORattler · 11-13-2013, 03:25 PM

Quote:

quote:Originally posted by bncinwv

About like one trip we were making and I thought the battery was dead, stopped at a Walmart in the wee hours of the morning, bought a battery, and the brand-new battery wouldn't work either?? It helps when the battery disconnect is not turned on!!! Returned battery, replaced the existing one, turned battery disconnect off, and went upon my merry, embarassed way!!!

Bingo

I think forgetting to flip the battery disconnect switch is part of the price we pay in our eternal quest for RV enlightenment

Phil P · 11-14-2013, 12:39 AM

Hi

What makes me think your truck isn’t supporting the trailer is the fact that you started the truck and couldn’t get the lights to work. When our battery failed the truck would light the lights and keep the refrigerator working on gas but didn’t provide enough power to run the hydraulic pump to close the slides.

When I started the truck the lights came on almost immediately.

Phil P

You may also like: