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NHcamper
07-08-2020, 05:40 AM
Question. I own a TT 2015 Keystone Laredo 322RL. Does the TT battery charge when hooked up to my truck or does the TT battery only charge when connected to 120 shore power? I was reading an article about a device that connects to the tow vehicle and then connects to the shore power cord so the TT battery can charge which is why the question.

wobly
07-08-2020, 06:28 AM
If your electrical system is operating correctly, your TT battery will charge when the 7-pin connector is plugged into the truck.

B-O-B'03
07-08-2020, 06:41 AM
If your truck is setup for it, it will charge the trailer battery while you drive.

For my F150, the charge line relay and fuse were in a little baggie in the glove box, the dealer never installed them.

Once I installed them in the fuse box, under the hood, the camper batteries would charge, while the ignition was on.

You can verify voltage at the 7 way plug with a volt meter.

-Brian

ctbruce
07-08-2020, 06:45 AM
Keep in mind that the wire to and from the 7 pin connector is small and does not move many amps. It will help trickle charge your battery but will not recharge a depleted battery very well.

gearhead
07-08-2020, 06:51 AM
My brother has a new F350. It wasn't charging his battery and he had no running lights on his trailer. After a day at the dealer a mechanic found a wiring harness plug that wasn't quite connected at the factory. Also was told the Ford schematic showed 30 amps available, but he might get just 10 amps.

flybouy
07-08-2020, 07:47 AM
Question. I own a TT 2015 Keystone Laredo 322RL. Does the TT battery charge when hooked up to my truck or does the TT battery only charge when connected to 120 shore power? I was reading an article about a device that connects to the tow vehicle and then connects to the shore power cord so the TT battery can charge which is why the question.

I have no idea what you are referencing here. As everyone has stated IF the truck is set up (most modern trucks are) properly it will. Ford's have a relay so it will only charge while running. I've heard some will be on all the time so if you stop for a while it can run down the truck battery and some will only energize if the truck is running and in gear.

As noted, if the battery is discharged very deep it will take hours of driving to recharge it. Could take 6 or more hours. Do not plug in the trailer shore power while the 7 way plug is plugged into the truck.The converter charges the battery according to the battery voltage. If you have the truck plugged into the trailer the converter will "see" the truck voltage and shut off it's charging to the battery at it will "see" the battery as charged.

If you find yourself with a dead battery and need to run the slides or jacks then use a good set of jumper cables from the truck battery to the trailer battery as thjat will carry a lot more amperage.

Logan X
07-08-2020, 08:49 AM
I have seen some people install a DC to DC charger directly from the trucks alternator to the battery bank. They typically run heavy gauge wire with this setup and can put 30 or 40 amps into the battery bank.

I have only seen people with large lithium battery banks do this and you would have to ensure the truck’s alternator could handle the extra load.

For a typical flooded lead acid battery bank, I think this would be overkill.

Here is a link to a DC to DC charger -

https://www.amazon.com/Renogy-Battery-Batteries-Multi-stage-Charging/dp/B07Q5VYPCF

And here is a link to a good install video -

https://youtu.be/ww_4yhQPGwY

flybouy
07-08-2020, 09:41 AM
That would require a seperate wire to the trailer battery as the wires in a 7 pin umbilical would carry a 30 or 40 amp load.

Logan X
07-08-2020, 10:07 AM
That would require a seperate wire to the trailer battery as the wires in a 7 pin umbilical would carry a 30 or 40 amp load.

Yes, this is what I have seen. You would run a heavy gauge wire, like 1 AWG or whatever is the appropriate size, directly from the alternator, to the DC to DC charger, and then to the battery bank. It’s a lot of work which is why I think it is overkill unless you have a very large battery bank and you need to substantially charge it while you are under way.

flybouy
07-08-2020, 10:13 AM
Yup, just didn't want the OP to think "gee, I can install that" and end up with the umbilical being a "fusible link".:facepalm:

busterbrown
07-08-2020, 11:03 AM
I installed a Renogy 40 amp DC to DC smart charger on my trailer. I had to run two 4 AWG wires from my TV's starting battery back to my trailer's battery box. The box houses the DC2DC charger.

The problem is two fold with the existing 7 pin connector. First, the amperage delivered over the one aux/charging wire in the trailer cord is very small in relation to the amp hour size of most deep cycle batteries. When the battery bank is larger than a single typical group 24, the charging capability of that 7 pin connector is diminished to something like a float charger or battery maintainer.

Secondly, there are no smart charging (multi-stage) characteristics to the 12 volt aux feed in the 7 pin connector. Absorption, bulk, and float charging states aren't defined and all the house batteries will see is one constant voltage. The DC2DC charger is a smart multi stage charger that's adaptable to all battery types and their respective state of charge (SOC).

So far, my Renogy has performed great on a couple short camping trips. The real test for it will be when we head out west this summer to boondock at multiple locations.

gearhead
07-08-2020, 11:28 AM
If you have the truck plugged into the trailer the converter will "see" the truck voltage and shut off it's charging to the battery at it will "see" the battery as charged.

Uh oh. I need to change my habits, I never thought of this.
Thanks!!

flybouy
07-08-2020, 11:46 AM
If you have the truck plugged into the trailer the converter will "see" the truck voltage and shut off it's charging to the battery at it will "see" the battery as charged.

Uh oh. I need to change my habits, I never thought of this.
Thanks!!

That's if the truck circuit to the umbilical is energized. Same thing as connecting a battery charger to the trailer battery while on shore power. Every once in a while someone will post a "is it ok" to do that thinking it will speed up the charging when in fact it stops it from charging.

gearhead
07-08-2020, 02:33 PM
That's if the truck circuit to the umbilical is energized. Same thing as connecting a battery charger to the trailer battery while on shore power. Every once in a while someone will post a "is it ok" to do that thinking it will speed up the charging when in fact it stops it from charging.

My hot wire from the truck to the camper is hot all the time. I need to remember and disconnect on overnight stops where I don't unhitch. I also keep the trailer plugged in to 120volt from the house overnight until just before we leave. I need to pull the truck cord until just before driving off.