Turn off engine battery

[KarenMN]

I bought a 2014 Thor Vegas this week. One of the technicians at the dealer told me I should turn off the engine battery whenever I'm stopped for any length of time, even if I have shore power. My brother-in-law, who was helping me through the purchase, was extremely skeptical. He has owned numerous brands of motor homes and never heard of such a thing. Since the process involves opening the hood every time, I wanted to check it out. Is this actually necessary? (I will mention that the technician knew very little about the Vegas.)

[JamieGeek]

Welcome to the site.

If you're plugged in the converter will charge the engine battery (make sure the use/store switch is "on").

In fact, whenever you're plugged in use/store should be in "use".

I put a knife switch on my engine battery and only disconnect it when I put the coach in storage and not plugged in.

If you haven't already you may want to download and read Ed's excellent crowd sourced Axis/Vegas owner's manual found here:
https://www.thorforums.com/forums/f1...nual-4961.html

[Oneilkeys]

I owned a Vegas and Axis for six years and never turned off the engine battery. I do not know any reason to do so, except if you are leaving the coach for a week or more, not plugged in. I could leave mine for 10-14 days without going below 11.8v, but I disconnected the second radio wire that lead to the engine battery. Turning off the engine battery turns off the engine computer which has to reset. Turning it off when on shore power means the engine battery does not get charged. It’s amazing the bad information you get from RV salesmen.

[dkoldman]

Originally Posted by KarenMN

I bought a 2014 Thor Vegas this week. One of the technicians at the dealer told me I should turn off the engine battery whenever I'm stopped for any length of time, even if I have shore power. My brother-in-law, who was helping me through the purchase, was extremely skeptical. He has owned numerous brands of motor homes and never heard of such a thing. Since the process involves opening the hood every time, I wanted to check it out. Is this actually necessary? (I will mention that the technician knew very little about the Vegas.)

Congratulations on new RV. My take on little info I read.

#1 If everything is working properly you certainly DO NOT need to disconnect Engine Battery when connected to shore power. Have your Brother In Law verify that when on shore power & in use mode; check that the battery is reading 13 plus vDC. Think about it; when connected to Shore Power and in Use mode your engine battery is being charged up

#2 May have been misunderstanding where you heard "stopped for any length of time"? Is it possible dealer was saying if it was going to be parked (without shorepower) for any length of time?

I bought a brand new coach and the 1st thing I did was buy a Battery Disconnect Switch for Engine. It was only $14 off ebay. I was going to install it myself, but my Winnebago dealer saw it and installed for me for $50 bucks including parts wires fuse etc. See picture to the upper right. I will ONLY use it to turn off when I plan to park the RV for an extended period of time (1 week or more with no shorepower), or at someplace where it may be unattended and I wish to ensure nothing is on just to make it harder for a would be thief. My battery is actually inside the coach under steps so they may just assume the battery is dead. It is also very easy for me to get to to turn on/off without have to pop that hood.

I put this switch as nice to have but not critical. With that said depending on how you may use.... you really may need one unless you are very active with the RV or have it on shorepowere 24/7?

[Bob Denman]

Since everybody else has you well-covered on the battery issue: I'll just say, "Welcome to the Forum!"

[KarenMN]

Thank you! Just one question: Where is the "in use" switch? I've been through the manual and haven't found anything about it.

[Oneilkeys]

That’s the Use/Store switch located just inside the door on the left. It must be I; the Use position for the lights, etc to work and for the house batteries to charge. I leave it on Use whenever I am using the RV and turn it to store only when I am finish a trip.

[Travelin' Texans]

Originally Posted by Oneilkeys

That’s the Use/Store switch located just inside the door on the left. It must be I; the Use position for the lights, etc to work and for the house batteries to charge. I leave it on Use whenever I am using the RV and turn it to store only when I am finish a trip.

But if it's like most OEM disconnects it does not totally disconnect all parasitic drains, your batteries may still be dead in as little as couple days unless you remove the positive or negative cable.

[Bob Denman]

Yup! The parasitic losses can be annoying. I added a pair of disconnect switches to the ground cables on each side of the battery compartment, and killed all of them.

[Oneilkeys]

Originally Posted by Travelin' Texans

But if it's like most OEM disconnects it does not totally disconnect all parasitic drains, your batteries may still be dead in as little as couple days unless you remove the positive or negative cable.

Or, in the case of the Vegas/Axis, you can just push the button on the 50 amp disconnect solenoid in the house battery box ( Far rear-left hand side) which disconnects the house batteries from the coach.

[DLL66]

Originally Posted by Bob Denman

Yup! The parasitic losses can be annoying. I added a pair of disconnect switches to the ground cables on each side of the battery compartment, and killed all of them.

I got a jack knife switch from amazon and put it on. I had to replace the battery already.

[Travelin' Texans]

Originally Posted by Oneilkeys

Or, in the case of the Vegas/Axis, you can just push the button on the 50 amp disconnect solenoid in the house battery box ( Far rear-left hand side) which disconnects the house batteries from the coach.

But does that switch "totally" disconnect the batteries or is it like I mentioned & leaves plenty of drain to kill the batteries in a few days.
My guess it does not totally disconnect! If I recall the LP/CO detector must be wired directly to the battery as per safety codes, not through that switch, also the slide & step motors.
Don't count on that switch or a factory installed disconnect to prevent dead batteries.

[saddlesore]

Originally Posted by Travelin' Texans

But does that switch "totally" disconnect the batteries or is it like I mentioned & leaves plenty of drain to kill the batteries in a few days.
My guess it does not totally disconnect! If I recall the LP/CO detector must be wired directly to the battery as per safety codes, not through that switch, also the slide & step motors.
Don't count on that switch or a factory installed disconnect to prevent dead batteries.

Just put the knife switch on the main battery ground cable.

[carlgorski]

Originally Posted by KarenMN

I bought a 2014 Thor Vegas this week. One of the technicians at the dealer told me I should turn off the engine battery whenever I'm stopped for any length of time, even if I have shore power. My brother-in-law, who was helping me through the purchase, was extremely skeptical. He has owned numerous brands of motor homes and never heard of such a thing. Since the process involves opening the hood every time, I wanted to check it out. Is this actually necessary? (I will mention that the technician knew very little about the Vegas.)

What? Not required at all. DOnt know what this guy was thinking.

[Bldcop]

Welcome, we also added the switch to disconnect because even when plugged in the engine battery would go dead and cause failure to the rest of the coach. Figured the charger was not cycling right so we replaced all the wires, added disconnects, replaced engine batteries (was time), replaced all fuses and found out what they ran while we changed them, charger, converter etc....opened up all compartments and cleaned them up. Thor left sawdust, trash, and a gerneral mess. There was miles of wires just sitting under there so all that is organized now. If your coach is like ours and it looks like it is, as we also bought a used 2014 Vegas 24.1, and if the previous owner didn’t already do the above upgrades it sounds like you may have to spend some time on your coach. The thing is you have to figure out what’s the most important to you, how much time you have, and money you want to spend before changing or upgrading things. So yes our battery’s would go dead in about a weeks time. We have done just about every upgrade on this site and some not on here, but plan on keeping and enjoying our coach for years. Can’t trade them in without a big loss, so go as much as you can, enjoy as much as you can. If I can help let me know.

[telcoman]

In most rigs the engine battery is not in the circuit unless the truck is turned on and the solenoid between the 2 is on. I bought a small solar panel & regulator and I used magnets to stick to the hood and connect it to the truck battery with aligator clips when parked for more than few days. it works well.

[Glensouth]

I never disconnect my chassis battery. Even when I have it in storage for a month. I always exercise my generator monthly. So I also start the engine and let it run and the chassis batteries never sound weak when starting it.

[dkoldman]

Originally Posted by Glensouth

I never disconnect my chassis battery. Even when I have it in storage for a month. I always exercise my generator monthly. So I also start the engine and let it run and the chassis batteries never sound weak when starting it.

Each coach is different with regard to drain on engine battery. If you can go a month you are in great shape. Some may need to go 3 or 4 months and not use or not start generator if not longer. I have never had to use my engine disconnect switch because my RV is stored at my home, but I have switch that I can turn off anytime I need (if I need). I may be able to go two months? I will never know because I don't have to try.

[sueasher1@netzero.net]

I have always had that problem with my 2014 Thor Axis and not being electrically inclined (I failed on the jackknife switch) I’ve used the “Emergency Start” switch to aid my engine start. What disconnect did you use between the coach and the engine?

[dkoldman]

Originally Posted by sueasher1@netzero.net

I have always had that problem with my 2014 Thor Axis and not being electrically inclined (I failed on the jackknife switch) I’ve used the “Emergency Start” switch to aid my engine start. What disconnect did you use between the coach and the engine?

Picture of what I used is in Post #4