Car Battery Died

Musictom

Member
Gold Supporting Member
Feb 13, 2021
97
Greetings, all.
So we just returned yesterday afternoon from a long, (30 day) successful trip. My wife and I want to do a thorough cleaning of the pup, so I didn't garage it right away, but parked it on the street.

After about four hours, I went to move the van/pup. Got in, and the van battery was nearly dead. Turns on lights, but won't turn on the engine.

Our pup and battery are only about 1 1/2 years old, but I'm wondering if at some point I let my pup battery drain too much. It seems not to hold much of a charge anymore, and it really surprised me that my car battery went down so quickly. (7 pin connector was connected the whole time).

It seems either a) I've significantly reduced my battery capacity or b) something in the pup is seriously draining the battery. About the only thing I can think of that would be on was the refrigerator. I did switch it over to 12 volt before driving home yesterday (we had a six hour drive, so I would think my pup battery would be pretty full).

Anyway, if there is an option 'c' I haven't thought of, that's why I'm posting. I would like to convert over to a Lifepo4, in order to do some longer boondocking, so this may be my incentive. Thanks!
 

Musictom

Member
Gold Supporting Member
Feb 13, 2021
97
Thanks for the replies! The fridge is only on 12 volt when we're traveling. When we got home, I remembered we still had some food in the fridge, so I figured I'd just leave it on 12 volt.

Lesson learned, and I am so glad I learned it in Camping Driveway, haha!
 

Snow

Super Active Member
Jul 19, 2007
12,272
Ontario
Actually two lessons learned:
1- the 12v setting on these fridges will drain a battery quickly, unless the battery is receiving a constant charge.. one reason why a lot of people with three-way fridges look at and try running them on propane (50-50 chance the flame will blowout). Those of us with two fridges have no option but with the larger fridges there is only a 5% chance the flame will blow out.

2- always disconnect the 7 way plug fron the tow vehicle if you are stopping any longer then 30 minutes.. For two reasons, first being the 12v fridge once it has depleted the trailer battery, it will discharge the vehicle battery. The second reason is basically the same (but with the fridge completely off). A discharged trailer battery will draw down and drain the vehicle battery as it wants to charge, basically you end up with two batteries close in actual charge but neither will start the vehicle.

It should be noted, not all tow vehicles (with a factory tow package) take the charge wire from after the ignition, lots take it from the before side. If you had the wiring afterwards (aftermarket, third party installer), there is a good chance the charge wire runs directly off the battery.
 

rsdata

Active Member
Oct 3, 2011
333
N. KY
do your homework before changing battery types... they are drop in replacements but that does NOT get everything in/out that the new battery types are capable of... good info found on youtube
 

undara12

Member
Mar 25, 2016
53
Actually two lessons learned:
1- the 12v setting on these fridges will drain a battery quickly, unless the battery is receiving a constant charge.. one reason why a lot of people with three-way fridges look at and try running them on propane (50-50 chance the flame will blowout). Those of us with two fridges have no option but with the larger fridges there is only a 5% chance the flame will blow out.

2- always disconnect the 7 way plug fron the tow vehicle if you are stopping any longer then 30 minutes.. For two reasons, first being the 12v fridge once it has depleted the trailer battery, it will discharge the vehicle battery. The second reason is basically the same (but with the fridge completely off). A discharged trailer battery will draw down and drain the vehicle battery as it wants to charge, basically you end up with two batteries close in actual charge but neither will start the vehicle.

It should be noted, not all tow vehicles (with a factory tow package) take the charge wire from after the ignition, lots take it from the before side. If you had the wiring afterwards (aftermarket, third party installer), there is a good chance the charge wire runs directly off the battery.
Do I understand correctly? My car came with a tow package. There is a pin on the connector that shows 12 volts with the ingition on but no voltage with it off. I assume that this is the lead that would supply current to the refigerator and I am OK to park with the ignition off and the connector left in place. Thank you.
 

Snow

Super Active Member
Jul 19, 2007
12,272
Ontario
Do I understand correctly? My car came with a tow package. There is a pin on the connector that shows 12 volts with the ingition on but no voltage with it off. I assume that this is the lead that would supply current to the refigerator and I am OK to park with the ignition off and the connector left in place. Thank you.
In your case, technically you can leave the trailer plugged in overnight since the 12vdc charge wire is switched by the ignition.. Myself, I would still unplug the trailer for the night.
 

Grandpa Don

Super Active Member
Sep 5, 2018
1,886
Southern California
A couple of years ago I had a similar problem I have the 3-way Fridge, but I only run it on Propane, never 12 volts. The only thing in my camper that uses 12 volts when closed up is the Gas detector, the Solar controller, and the main converter. I just returned from a week-long camping trip in the high Sierra mountains. I stopped at my son's house to spend the night before heading back home. I did not disconnect the 7-pin plug from the TV. I just didn't think about it. The battery in the TV was fairly new. Maybe a year old. When I went out in the morning to start the engine and head home. Guess what? I turned the key to start and all I heard was clinking from under the hood. The battery was nearly totally dead. Fortunately, my son had one of those portable Quick Start charger things. I connected it to the TV battery and hit the key again. It instantly started. After it started, I verified that my alternator was charging with a volt meter. When I got home I had Auto Zone test my battery, which tested good also. I never did figure out what item in the camper had such a draw on the battery. I just never left the 7-pin plug in when I stopped for more than a 30 minutes or so. I suspect that it was my controller. I guess it draws enough power to drain the battery overnight. That was a couple of years ago, and I've never had a dead battery since. Lesson learned!

I know there is a battery isolation device that I can install to prevent this. But I just never got around to researching it or getting one.
 
Last edited:

bondebond

Super Active Member
Aug 14, 2008
2,330
I know there is a battery isolation device that I can install to prevent this. But I just never got around to researching it or getting one.

I did - researched it and bought one. It's been sitting on a shelf in the shop, collecting dust for years. Unplugging the 7-way plug works without having to deal with the battery isolator in your TV. Sometimes simple is best.
 

poppy65

Member
May 10, 2015
93
Greetings, all.
So we just returned yesterday afternoon from a long, (30 day) successful trip. My wife and I want to do a thorough cleaning of the pup, so I didn't garage it right away, but parked it on the street.

After about four hours, I went to move the van/pup. Got in, and the van battery was nearly dead. Turns on lights, but won't turn on the engine.

Our pup and battery are only about 1 1/2 years old, but I'm wondering if at some point I let my pup battery drain too much. It seems not to hold much of a charge anymore, and it really surprised me that my car battery went down so quickly. (7 pin connector was connected the whole time).

It seems either a) I've significantly reduced my battery capacity or b) something in the pup is seriously draining the battery. About the only thing I can think of that would be on was the refrigerator. I did switch it over to 12 volt before driving home yesterday (we had a six hour drive, so I would think my pup battery would be pretty full).

Anyway, if there is an option 'c' I haven't thought of, that's why I'm posting. I would like to convert over to a Lifepo4, in order to do some longer boondocking, so this may be my incentive. Thanks!
Check you battery connections make sure they are clean. Start the car and disconnect the positive cable if the car keeps running its your battery and sometimes in the pup is pulling it down. If the car quits running then it's you alternator
 

Hilldweller

Super Active Member
Mar 2, 2021
1,057
Hog Waller, GA
One of the big reasons I got rid of the little LA battery and put in a 100 ah LiFePo4 battery. I've had no trouble at all running my fridge on DC while towing. Even 10 hour days on the road. When I get to the campground I either plug in or hit the solar and top the battery back off.

The alternators on most TVs can't keep up with the drain an absorption fridge creates. Compressor fridges rule.
 

fronsm

First time owner at 67
Jul 1, 2020
114
Indiana
DC means dead car, tow with the fridge on propane if a 3 way fridge.
I heard it was illegal to tow with the fridge on propane. And you can't have an open flame at a gas station if you should happen to stop. I tow with a 7:00 p.m. and use the 12 volt for the fridge. When I stop for more than a quick lunch, I unplugged the seven pin. I learned my lesson with a seven pin hooked up and a dead battery in my vehicle.
 

fronsm

First time owner at 67
Jul 1, 2020
114
Indiana
In your case, technically you can leave the trailer plugged in overnight since the 12vdc charge wire is switched by the ignition.. Myself, I would still unplug the trailer for the night.
I have a tow package with a seven pin connector and my battery went dead in my tow vehicle. Not sure I understand your response.
 

vggbrgr

New Member
Mar 23, 2016
2
DC means dead car, tow with the fridge on propane if a 3 way fridge.
I’d add to that “where allowed by law”. I’d have to shutoff and reopen my propane prolly 3-4 times before I got out of the city. Trust me there’s often only ONE chance to pull over before entering a tunnel. Not worth it and it’s not like my battery is going to drain any while the vehicle is running.
 




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