12V charging through 7-way connector

[mvk1287]

I'm not charging my 12v fridge & battery through my 7-way while connected and pulling my tow trailer. Battery checks fine, solar charges fine, shore power charges fine, just not through my truck's 7-way. Any assistance/ideas are appreciated.
thank you

 

[SniperDroid]

You sure you have a 12 volt fridge?

 

[andymax]

And have you verified with a voltmeter that you are actually getting 12V from your truck? Specifically, Pin4+ and Pin1-.

 

[Travelin Ram]

Are you using a 12v compressor fridge, or absorption? Second type uses a LOT of power.

You won’t get much amperage from the 7 pin because the wires are long and small gauge.

 

[Tulecreeper]

Check that you're getting power between the Ground and the 12V contacts on your 7-pin connector. A test light will work, but I'd use a multimeter just to verify you're getting ~12 volts.

 

[2003F350]

It takes a pretty good amount of time to charge a drained trailer battery through the 7-way round. That said, it's never been an issue for me.

But definitely grab a multimeter and check your pins, you MAY have to have the truck on, I believe at some point to activate the 12v circuit the truck needs to 'see' the trailer connected.

 

[Tulecreeper]

It takes a pretty good amount of time to charge a drained trailer battery through the 7-way round. That said, it's never been an issue for me.

But definitely grab a multimeter and check your pins, you MAY have to have the truck on, I believe at some point to activate the 12v circuit the truck needs to 'see' the trailer connected.

I originally thought that, too. But I found that there is power to my 12v pin all the time.

 

[18CrewDually]

Just like @Tulecreeper said, test light or meter on the 12v (1 o'clock) and ground (7 o'clock) tabs.
You should have power all the time. This plug is where I hook up a battery maintainer in the winter. If no 12v then check the fuse to make sure it is not blown, more likely is if no power.

 

[mvk1287]

Thanks for the reply. I'll check the 7-way pin for the 12v. The rv battery is good, shore & roof solar does charge ( realize the solar doesn't charge fast) the battery. Readout is 100% when I first disconnect shore power and drive. After a longer drive, 5/6 hours checking readout its down below 20-25%. I only know of the 12v fridge drawing from it (maybe some trickle of something else small) so at a boondock with only a light & fridge the battery depletes quickly. I'll check the pin f/12v on the 7-way first, thank you

 

[mvk1287]

Thanks for the pin out diagram. That's what I just started looking for. I did locate the 30 amp ( fuse 201) in the secondary/internal fuse block ( a bear to get to under the steering column unless your skinny & flexible...hahaha). It checked ok...

 

[18CrewDually]

Make sure you're not leaving too much on or forgetting about turning off the furnace. My wife left the heater on once and it ran all the way home from FL to NJ in January.
You could always pickup an analog AMP gauge and wire it in series on the camper to see how many amps are drawing. Anything over about 15amp and the truck may not keep up.

 

[mvk1287]

Do have a 12v compressor fridge. Checking pin output first as suggested. 30a fuse in the internal fuse block was good. Thank all for the inputs, let ya know the outcome.

 

[GTyankee]

How do I keep my trailer battery charged while driving?



If you have a 7-way connector that is wired directly to your vehicle's starting battery, your trailer batteries will get a small trickle charge while driving.

many posts on charging the trailer battery

should you use your Ram truck to keep the trailer battery charged - Google Search

 

[Longhorn1500]

I have a bit different situation. I installed LiFePo4 batteries in my trailer. They run a higher voltage than lead acid, so the normal 7-way charging doesn't do much. So I installed a dc-dc charger in the trailer. It may also help with charging lead acid batteries in the trailer as there is a voltage drop in the charge wire. I went with a Renogy 20 amp dc-dc charger that has a 10 amp setting too. You can also get higher current dc-dc chargers, but for that you need to run a new higher gauge wire, some people even add another connector on the bumper, usually an Andersen connector.

 

[Tulecreeper]

I have a bit different situation. I installed LiFePo4 batteries in my trailer. They run a higher voltage than lead acid, so the normal 7-way charging doesn't do much. So I installed a dc-dc charger in the trailer. It may also help with charging lead acid batteries in the trailer as there is a voltage drop in the charge wire. I went with a Renogy 20 amp dc-dc charger that has a 10 amp setting too. You can also get higher current dc-dc chargers, but for that you need to run a new higher gauge wire, some people even add another connector on the bumper, usually an Andersen connector.

True, the LiFEPO4 batteries do need a higher charge rate than a LA battery to get them up to 100%, but a standard LA charger will still get it to 80+ percent. Not optimal, but good enough for a short period until a person could acquire a lithium charger.

 

[GTyankee]

If i were to start tent camping again, i think that i would buy one of those Jackery Solar Generators.



Looks like they are about to have a good deal on the Black Friday Specials

 

[RickyJ108]

I originally thought that, too. But I found that there is power to my 12v pin all the time.

check battery voltage before you plug in the trailer plug. Check again after it's plugged in you should have truck battery voltage minus a volt or two for wire loss. If you have battery voltage it's going to be charging it. Did you turn on the propane for the fridge? I learned this year the propane fridge needs more time to cool net year we will be starting it the day before as our camper is parked away from our house.

 

[Scherm]

My TT fridge is propane or 110. It will not work on 12v.
its a no no to drive and power the fridge through propane. Dangerous. We always get the fridge as cold as possible via propane or 110 before we hit the road.

 

[DRam2019]

Couple questions here….
1: are you traveling with the fridge on?
2: how many amp hour is your battery?
3: what’s the amp draw when fridge is on?

 

[Utah]

Some trailers have the wire block and not connected to the trailers 12 volt system. I have had a 2019 fifth wheel that the wire was capped and my bumper pull does not have the wire connected. A 12 volt refrigerator will drain two 12 vt batteries in about 8-10 hours. They are a battery hog. I know since i have one. I would go back to propane if i could.