Tow Vehicle Battery Drained

[jbflag21ds]

Install a DC2DC charger setup and disconnect the power from the 7-way. Either via a switch or permanently.

[Comanchecreek]

Originally Posted by jbflag21ds

Install a DC2DC charger setup and disconnect the power from the 7-way. Either via a switch or permanently.

I used the power from the 7 way connector to turn the DC to DC charger on and off. I wired a relay that connects and disconnects the power to the 7 way when the key is off, and when the key is on, it turns on the charger. It also energizes the wire when towing other trailers without the charger. Some people use a simple on off switch also. It's a matter of preference. Here's an example of what you can use.

https://www.amazon.com/Recoil-Automo...443081&sr=8-11

[DouglasReid]

Originally Posted by Comanchecreek

I used the power from the 7 way connector to turn the DC to DC charger on and off. I wired a relay that connects and disconnects the power to the 7 way when the key is off, and when the key is on, it turns on the charger. It also energizes the wire when towing other trailers without the charger. Some people use a simple on off switch also. It's a matter of preference. Here's an example of what you can use.

https://www.amazon.com/Recoil-Automo...443081&sr=8-11

Ya know, I looked at those relays and I see they are rated at 30/40 amps. The problem I see is the leads seem to be small for continuous 30 amp service.

I looked the table up online and the minimum size wire is #8 which definitely seems much larger than the leads.

Perhaps you or someone else can tell me how that works out? I am not one to use wire sized too small for the current and just "hoping it will be OK".

[Jim in Halifax]

My understanding that altenator charges rv battery when engin is running only...I always pull the plug from my truck even for overnights never had a problem yet...Touch on wood!!!!!!!!!!!!!!!!!!

[DouglasReid]

Originally Posted by Jim in Halifax

My understanding that altenator charges rv battery when engin is running only...I always pull the plug from my truck even for overnights never had a problem yet...Touch on wood!!!!!!!!!!!!!!!!!!

That is true but unless you have an isolation relay any direct connection through the 7 way receptacle will draw current from the battery...........possibly resulting in a dead battery and no way to start ur truck

[Comanchecreek]

Originally Posted by DouglasReid

Ya know, I looked at those relays and I see they are rated at 30/40 amps. The problem I see is the leads seem to be small for continuous 30 amp service.

I looked the table up online and the minimum size wire is #8 which definitely seems much larger than the leads.

Perhaps you or someone else can tell me how that works out? I am not one to use wire sized too small for the current and just "hoping it will be OK".

This circuit is only carrying enough juice to activate the on/off for the charger. Very little amperage. You need to run separate 6-8 gauge wire to actually run the charging on the unit. Look on YouTube. There are a number of videos on the subject of DC to DC chargers.

[Half Ton Heavy]

Originally Posted by DouglasReid

That is true but unless you have an isolation relay any direct connection through the 7 way receptacle will draw current from the battery...........possibly resulting in a dead battery and no way to start ur truck

No, not on any recent ford anyway. Motor not running= zero power at the 7 way.

[DouglasReid]

Originally Posted by Half Ton Heavy

No, not on any recent ford anyway. Motor not running= zero power at the 7 way.

So what you are actually saying is that the current Ford trucks incorporate a battery Isolation relay installed at the factory..............If in fact you have power to that 7 way when the engine is running.

[Comanchecreek]

My older Chevy required a fuse in the main fuse block be put in to activate the pin for auxiliary battery charging. The location and wiring were there, but no fuse. Not sure on the fords, but I would bet that it is probably a similar situation depending on the "Package" that was purchased. I know the newer trucks now offer a "fifth wheel package". With my older Chevy I found that the output at the connector, while the right voltage was low amperage. Small 10 gauge wire didn't carry much current, and my batteries just never got much of a charge. I have converted to a DC to DC charger, and hopefully that will help the situation. My guess is that the voltage regulator in the alternator senses that the truck batteries are charged and lowers the voltage output.

[Flybob]

[QUOTE=gjarrette;2506132
Also I did not have the emergency brake switch safety disconnect pulled out I know this will apply the trailer brakes on. Learned that the hard way.[/QUOTE]


I may be misunderstanding this comment, but pulling out the breakaway safety switch activates the battery. It does not disconnect it. There is no breakaway switch disconnect that I am aware of. Pulling this out will kill the battery quickly and can damage the brakes if powered for an extended time.

[Bogieboy]

Originally Posted by Flybob

I may be misunderstanding this comment, but pulling out the breakaway safety switch activates the battery. It does not disconnect it. There is no breakaway switch disconnect that I am aware of. Pulling this out will kill the battery quickly and can damage the brakes if powered for an extended time.

i think that is what he was saying, that he did not pull the breakaway, which would have caused significant battery drain.

[NJKris]

Thank you for confirming this would happen if I left TT plugged into truck. I always unplug because I was afraid this would happen, now I know for sure it will. It is surprising that your fully charged TT batteries would allow the truck to drain.

[bbells]

Hold on a second here. 400w solar should easily keep your rv battery charged. Even if the worst case scenario it is winter and you are in the north country and your watts are cut in half due to a flat roof and low sun. You need to check your solar controller and solar output. Put an amp meter set to 20 amps dc on the contacts of the solar panels going to the controller. You should show at least 10 amps when the sun is out. If you only have a 10a meter, wait until about five o'clock to check it. Then check the display. Is the solar charging the battery? I bet it isn't. IMHO, there is a good chance you have a bad solar connection or controller.

[Hawk on the Wing]

Originally Posted by Bogieboy

apples to apples, i thought the battery doctor was cheap...LOL the other 150 capable ones i saw were more in the 150+ range... (i would run at least whatever amperage your TV puts out for charging, but i am known for total overkill...LOL)

I have Battery Doctor 150 and I think that is more than adequate for charging a TT and my FJ Cruiser has a huge alternator. Keep in mind that when you install the Battery Doc you put in an in-line fuse. With a long stretch of 8 ga wire going to your TT battery, 30 amps would probably start heating up the wire pretty good so 30 amps would be about max for that fuse. The big Battery Doc (I think it's 250 amps) is really for an auxiliary battery right next to your regular battery and connected with a massive battery cable.

[jaudet71]

I found that a fridge on propane uses some battery power for management.

[DouglasReid]

Originally Posted by Comanchecreek

I used the power from the 7 way connector to turn the DC to DC charger on and off. I wired a relay that connects and disconnects the power to the 7 way when the key is off, and when the key is on, it turns on the charger. It also energizes the wire when towing other trailers without the charger. Some people use a simple on off switch also. It's a matter of preference. Here's an example of what you can use.

https://www.amazon.com/Recoil-Automo...443081&sr=8-11

Ive got an update. Just to be sure I called one of the manufacturers, Dorman, and it is rated for 30 amps continuous, so it is a perfect solution.

[LeoS]

As a previous owner of a similar Freedom Express trailer, I believe I can help solve the mystery.

This trailer generally comes equipped with an LCI electric tongue jack. This particular jack has two switches on the front of it; one for the loading light and one for moving the jack up and down.

In their infinite wisdom, LCI chose not make these switches waterproof. When it rains, water leaks down into the light switch and turns the loading light on, which drains the battery.

I thought about buying a special weatherproof cover for the top section of the tongue jack, but ended up just placing a kitchen trash bag upside down over the jack and taping it in place whenever it was going to be sitting out in the weather.

Hope this helps.

[Pud]

[QUOTE= I'm old and have always done this since I was a kid. Better safe than sorry.[/QUOTE]

Once I left my hauler connected for three months and it ate both the RV Main and Aux batteries as well as the House Battery !

Turns out the trailer emrgency battery was dead, acted shorted, and that ate my RV batteries.

Patrick
2005 Dynaquest

PS: We have a 2019 F-250 and it's horse trailer is always connected and not a single problem with batteries.

[Comanchecreek]

Originally Posted by DouglasReid

Ive got an update. Just to be sure I called one of the manufacturers, Dorman, and it is rated for 30 amps continuous, so it is a perfect solution.

I have to tell you that my installation was my winter/covid project. TitanMike helped with the setup. I used 8 gauge Marine grade bonded wire to run power from the TV battery through a 40 amp maxifuse, and installed the relay on the original circuit that goes through the 7 way plug to control the on/off function of the DC to DC charger and has a 30 amp fuse in the fuse block. You can buy those relays for less than 8 bucks on Amazon. As to durability, I'll have to let you know. My first road trip is in May where we will be doing some dry camping in between RV parks. I have used this type of relay in other applications, and they have held up well. Usually it takes a dead short to take them out. I'm definitely carrying a spare just in case.

[Chuck_S]

It is/was common for the GM pickups/SUVs to lack the 12v "trailer battery charge" connection at the rear until a relay and fuse were inserted in a box under the hood.

No problems discharging the truck battery on any of my Ford SUVs where all connections to the rear run thru relays and and are Off unless the ignition is On. Just verified this 3 minutes ago on my Expedition. All connections there are dead with the ignition off. The battery charge goes live with the ignition as does a tiny pulse of the brake and lighting connections as the built in brake controller checks to see if there's a trailer back there and the system confirms all the lights on the trailer are good. First time I connected my Roo to this SUV an alert came on the dash that a specific light on the rear was dead. Yeah, right, I thought. But sure enough it was.

-- Chuck