Battery switch trouble?

The_Rigger

Took the T@G up north for a two day trip in the Straights of Mackinaw, and heading home I noticed something kind of odd…

How often do battery disconnect switches fail? Or, to put it another way, the battery disconnect switch is supposed to disconnect everything, right? The reason I ask is I still have interior lights and a working stereo, regardless of which way the switch is turned.

Bad switch or bad wiring? Or maybe I got a little rain water in where I don't really need it, in the battery box? The trailer did get a pretty good soaking in the past 48 hours....

ras

On our 2016 T@G, the switch disconnects the T@G electrical system from the Tow Vehicle electrical system. The purpose I assume, is to ensure that you don't drag down your Tow Vehicle battery. On while driving to charge the trailer battery; off while camping to ensure you can start your vehicle later. If you're plugged into AC power at your camp site, it doesn't matter because you're not discharging your trailer battery but if you're boondocking and the TV and trailer are connected, it's crucial. If you want to kill the interior systems, you need to open circuit breakers or pull fuses or remove a battery cable.

JamesDow

Sounds like water may have shorted the switch. Maybe it may dry out fine, but if not the switch costs around $20 on Amazon. Where in UP did you go? Was a great trip for us in 2021.

The switch disconnects the battery from the T@G. If not on shore power/generator, nothing should be hot if turned off.

I would guess a switch change is in order.

The_Rigger

I was heading home today, hooked up to the tow vehicle at a fueling stop in Gaylord, and a guy at the next pump over was admiring the T@G so I gave him a quick look inside - he initially didn't believe the thing held a for-all-intents-&-purposes King-sized bed. I just happened to see the LED screen on the stereo was lit up, making me think I had pulled out from camp and forgotten to switch off the battery. Just for giggles I hit the switch for the ceiling "island" LEDs and they lit up too. But when I looked inside the tub, the switch was in the OFF position. Switching it back and forth didn't have any effect on the lights or the sound system. Could they have been powered off the tow vehicle's battery? That doesn't seem correct to me. OTOH I seem to have several wires connected to the battery's B+ terminal, only one of which is routed through the battery switch. I know one wire is my feed from the tow vehicle to charge the camper battery and power the trailer brakes, one is the B+ wire from the extra solar panel socket on the side of the tub, I assume one runs to the WFCO, and I have no idea what wire #4 goes to... Possibly to the Victron controller? I guess I'm gonna have to go visit a local nüCamp dealer and see if I can sweet-talk a 2021 T@G wiring schematic out of their Service Dept.

@ras, I was on shore power with the tow vehicle disconnected all weekend - I never camp with the camper plugged into the tow vehicle; that way lies madness and a roached Subaru battery. I keep the battery switched off while towing, which IIRC lets the tow vehicle charge the battery and power the trailer brakes without having the whole camper powered up, for safety's sake. Maybe I'm doing it wrong?

@JamesDow, I spent Sunday and Monday nights at the Straights State Park, just outside St. Ignace, using it as a "base camp" for some Monday daytrips to visit friends in Escanaba, Seney, Newberry, and Trout Lake. Drove up Sunday morning, drove back downstate this afternoon. Quick 'n' dirty mini-vacation, but good to get away, plus I now have a freezer-full of Lehto's pasties, and that makes it all worthwhile.

Sharon_is_SAM

@The_Rigger - what you experienced, is normal. See below for a check regarding charge line and isolation relay.
You do not have an isolation relay and the charge line remains active. BTW, you should tow with the battery switch on. If, off, in the event of a complete separation from the tow vehicle, the brakes will not engage. The break-away switch is powered by the TaG battery.

Turn off the battery switch, and then hook up your camper to the 7-pin, crank the engine.
Turn on an interior trailer light. If it comes on, you have a charge line.
Turn off the engine, if the light goes out, you have an isolation relay.
If the light stays on, you do not have an isolation relay.

ras

@The_Rigger said:
I was heading home today, hooked up to the tow vehicle at a fueling stop in Gaylord, and a guy at the next pump over was admiring the T@G so I gave him a quick look inside - he initially didn't believe the thing held a for-all-intents-&-purposes King-sized bed. I just happened to see the LED screen on the stereo was lit up, making me think I had pulled out from camp and forgotten to switch off the battery. Just for giggles I hit the switch for the ceiling "island" LEDs and they lit up too. But when I looked inside the tub, the switch was in the OFF position. Switching it back and forth didn't have any effect on the lights or the sound system. Could they have been powered off the tow vehicle's battery? That doesn't seem correct to me. OTOH I seem to have several wires connected to the battery's B+ terminal, only one of which is routed through the battery switch. I know one wire is my feed from the tow vehicle to charge the camper battery and power the trailer brakes, one is the B+ wire from the extra solar panel socket on the side of the tub, I assume one runs to the WFCO, and I have no idea what wire #4 goes to... Possibly to the Victron controller? I guess I'm gonna have to go visit a local nüCamp dealer and see if I can sweet-talk a 2021 T@G wiring schematic out of their Service Dept.

@ras, I was on shore power with the tow vehicle disconnected all weekend - I never camp with the camper plugged into the tow vehicle; that way lies madness and a roached Subaru battery. I keep the battery switched off while towing, which IIRC lets the tow vehicle charge the battery and power the trailer brakes without having the whole camper powered up, for safety's sake. Maybe I'm doing it wrong?

,
Obviously some differences between models. On our 2016 T@G 5W , the switch "unplugs" the T@G and the tow vehicle so the T@G can't draw down the TV battery. Unplugging on arrival and reconnecting before traveling seems to perform the same function as the switch. I'm not the first owner so I can't guarantee that ours is performing the factory function. And don't have trailer brakes so that has never been a problem. Usually tow with my 4 Runner but when we tow with my wife's 2019 Subaru, we've learned we need to turn the Subaru's headlights on to raise the output from the energy efficient variable output alternator. Since the 7 pin is connected straight to the battery (thru an in-line fuse), it bypasses the Subaru computer and a low trailer battery does not trigger a higher output from the alternator.

The_Rigger

I spoke to the Service Mgr at one of the local nüCamp dealers today. He's never heard of any camper acting the way mine did before, and he's wondering if maybe it's wired - either accidentally or on purpose - in such a way that the OEM solar array and Victron controller are back-feeding power into the DC side of the electrical system.

He is going to see about getting a wiring schematic of a model year '21 T@G from the factory so we can trace everything down and see what's what. (And yes, I did ask for a copy of it, in case he gets one.)

@ras I normally run my Outback (an '18 Limited) with the parking lights on when towing during the daytime, just to be sure the alternator puts out maximum current. I can count the number of things I dislike about my 5th-gen Subaru on the fingers of one hand and still have a finger or two left over, but that so-called energy-efficient alternator is definitely one of the things that gets a finger (and I'm sure you can imagine which one).