Battery isolator

Photomom

I am making arrangements with a trailer shop to get my SUV ready to pull the T@B. I'm having trouble making him understand what I want in terms of a battery isolator - i.e. a relay or solenoid device that cuts power to the charging line when the ignition switch is off.

He called today and wanted to know if we wanted the "switch" inside the cab or under the hood. This tells me that he has no familiarity with this kind of device. He finally had me email him a picture of one.

How many people have one of these things on their tow vehicle? I was under the impression that people would have them as a matter of course and it would be no biggie to get one installed.

jkjenn

Photomom said:

I am making arrangements with a trailer shop to get my SUV ready to pull the T@B. I'm having trouble making him understand what I want in terms of a battery isolator - i.e. a relay or solenoid device that cuts power to the charging line when the ignition switch is off.

He called today and wanted to know if we wanted the "switch" inside the cab or under the hood. This tells me that he has no familiarity with this kind of device. He finally had me email him a picture of one.

How many people have one of these things on their tow vehicle? I was under the impression that people would have them as a matter of course and it would be no biggie to get one installed.

My T@b dealer wouldn't touch it. You will have better luck with a local vehicle repair shop or your car dealer.

mash2

I had mine done at trailer store.  No issue with mine.  Installed under the hood.  If he is unsure, I'd try someone else.  

Photomom

ST_Bob said:

A 40 amp automotive relay will handle the charge line (which should be fused at 30 amps).  Power comes into the relay on pin 30 and goes to the trailer's charge wire on pin 87.  Relay is powered from pins 85/86.  Tie your chassis ground wire to 85 and an ignition-switched source to 86.  Whenever the ignition switch is on, the relay will close and send power to the charge line.

@ST_Bob what and where are these PIN numbers?

Photomom

Is this the kind of thing you're referring to? http://www.amazon.com/Auto-Truck-Relay-Socket-SPDT/dp/B007JPPQH6

And not this: 
http://www.amazon.com/Stinger-SGP32-Battery-Relay-Isolator/dp/B001HBYXVS/ref=sr_1_3?s=automotive&ie=UTF8&qid=1459249921&sr=1-3&keywords=Battery+isolator

Photomom

We just talked to a SECOND trailer place and they had no idea what a battery isolator is either! What the heck?

ScottG

Photomom, if the manufacturer offers an OEM tow package for your vehicle, you might look into having a dealer install one.

My TV came with a factory hitch and harness, but my impression is that vehicles with this option already have the infrastructure in place so that installing the harness (and its associated fuses and relays) is plug and play (assuming you know where and what to plug...).

I'm guessing a regular shop may resort to just splicing wires into your existing TV harness. No reason that can't work, but an OEM installation is likely to be more reliable and elegant. Of course, you'll pay for that advantage if a dealer does the work.

Back to your original question. My OEM trailer wiring cuts the power to the T@B battery when the engine is off. This may not apply to your particular vehicle, so be sure to ask the right questions if you go this route.

Photomom

I have the 2013 Highlander Plus 4WD which came with a heavy-duty radiator, engine oil cooler, 200-watt fan coupling, transmission oil cooler and 150-amp alternator. Basically a passenger vehicle that you could add a hitch and wiring to and tow up to 5000 pounds. In retrospect I think the 4Runner might have been a better choice since it came with a hitch and wiring, but we didn't anticipate getting a travel trailer then. I'm confident we'll get there, but this is a learning process.

Taking it in to Trailer Place #1 tomorrow and we'll keep our fingers crossed.

Verna

@Photomom...question....  When you turn your key off in your Toyota Highlander, do your accessory plugs lose power?  My plugs are dead when the ignition is off, as is my 7-pin connector. Which means your Highlander may already have a battery isolator. 

Do you have a volt ohm meter to verify whether the 7-pin connector is wired through the battery isolator? If there is no power at the 7-pin connector with the ignition turned off, then you don't need an additional battery isolator.  

If you have power all the time on your 7-pin connector, you just need the wiring rewired to Toyota specs so the 7-pin connector is off when the ignition is off. 

Mouseketab

Also another easy way to tell.... disconnect your camper battery or pull the fuse, connect your 7-pin, crank your engine and turn on a light in the camper. If the light comes on, you have a charge line. Turn off the engine, if the light turns off, you have an isolator, if the light stays on, you do not have an isolator.

Photomom

@Verna, thanks, that is very timely. We might wait on the isolator. 

Verna

Photomom said:

@Verna, thanks, that is very timely. We might wait on the isolator. 

Sorry I didn't think of it before. I had to look up Highlander to
find out it was a Toyota. 

Photomom

Thanks, I have one of those on my Amazon wish list. 

They are are working on the car as I write this. We decided to hold off on the battery isolator for now. Our first real road trip won't be until late July so we've got time to figure it out. The trailer guy is going to leave some extra wire so an isolator can be added later. I might talk to the dealer next time I have the car in for service and get their recommendation.