Community Forums

Blue Hill · 04-27-2015, 02:23 AM

I've been thinking about installing a battery isolator to keep my truck and trailer batteries separate. On doing some research, I find two camps on this issue. Some say it's a must do, while others say not necessary. What do you folks think? Thanks for your help.

twinboat · 04-27-2015, 04:14 AM

You could pull the trailer plug, at night.

I would put a relay under the hood that only connects the charging wire, when the key is on.

Another option is get a Yandina or Victron, battery combiner. A very simple fix. Find the wire, in your truck, that supplies trailer power, cut it and and hook it in between.

Isolators are old technology and need more installation work. Plus there is some voltage drop thru them.

You could just get a 30 amp diode and wire it in. They work like a one way valve, only letting power travel to the trailer. Problem is, the voltage drop, again.

There are many ways to do what you want to do.

Good luck

the_vfox · 04-27-2015, 04:25 AM

You didn't say what your tow vehicle was, my Chevy 7 pin plugs only supplies power to the trailer when the Key is on. Powering your trailer also charges the trailer battery, important when you need your emergency disconnect switch.

marcham · 04-27-2015, 05:55 AM

As mentioned above, if your vehicle was not factory equipped with a 7 pin trailer plug then adding a relay for the battery charge pin is th3 the best option. Also, you'll need at least 8 gauge on that wire from the battery to the 7 pin connector. On my highlander, I had tapped into the vehicle's position lights, I just turned them on if I wanted to activate the relay.

Blue Hill · 04-27-2015, 07:38 AM

Quote:

Originally Posted by the_vfox

You didn't say what your tow vehicle was, my Chevy 7 pin plugs only supplies power to the trailer when the Key is on. Powering your trailer also charges the trailer battery, important when you need your emergency disconnect switch.

Sorry. TV is a 2011 Chev 1500 and the terminal is hot all the time, regardless if the key is on or not.

marcham · 04-27-2015, 08:14 PM

That can't be right... I'm wondering if maybe the relay has failed in the closed position.

GoldWing2003 · 04-27-2015, 08:18 PM

I agree with marcham, the terminal should only be hot when the ignition is on. Did someone modify the wiring or was it added after the fact and possibly installed incorrectly.

Blue Hill · 04-27-2015, 09:58 PM

Quote:

Originally Posted by GoldWing2003

I agree with marcham, the terminal should only be hot when the ignition is on. Did someone modify the wiring or was it added after the fact and possibly installed incorrectly.

Came from the factory not connected. I couldn't understand why the power terminal in the 7 pin did not have power, so I searched online for a solution. I learned where the wire was located under the hood (it had a connector already on it) and which terminal in the fuse box to connect it to. I also had to buy the special fuse to complete the circuit.
Everyone has been telling me to simply make sure that I unplug the 7 pin if I leave the trailer connected overnight. If the circuit was not hot all the time, what would be the need to unplug the connector?

Skip426 · 04-27-2015, 10:12 PM

Quote:

Originally Posted by Blue Hill

If the circuit was not hot all the time, what would be the need to unplug the connector?

If the charge circuit is dead when the ignition is off , you don't need to unhook the trailer wiring over night.
Most newer trucks with the trailer tow are equipped with the relay to shut the circuit off, so the owner doesn't have to remember to re-connect in the morning; and drive off with no lights or trailer brakes.