O2 sensor going off

I just stored my trailer for two weeks away from home (usually kept hooked up to elect). I brought my battery home to make sure it was fully topped off. I debated the need to bring it back when I was just towing trailer home...then reminded myself that the breakaway switch was powered by the trailer battery!! Definitely an essential!! So I brought it, and towed home well. Also, I always need to remind myself to make sure I know which side is positive and which negative. Getting mixed up is not good!

I was on vacation for a week and couldn't get to RV.net so I'm working through the withdrawals by posting even to older questions.

If you leave the battery connected in storage the various devices will drain the battery. Based on your post there are really two solutions.

• Disconnect the negative cable of the battery for storage.
• Install a battery disconnect switch so you can disconnect the battery while in storage.

Yes you want the battery to be charged before hand as storing a battery in a partially discharged state will damage it.

The only caveat I'd add is to make sure you reconnect the battery cable or turn the switch back on before you tow the TT. If you don't you won't have brakes on the TT.

Kittykath wrote:
We're currently fixing up a popup camper. We had an extra used CO detector, put new batteries in it, then attached it near the furnace in the camper. Within a week, it started to chirp every 30 seconds. The propane tank hadn't been connected yet and all the screens were open. Hmm. Put new batteries in again. Same thing.

The fine print on the detector explains that once it reaches 7 years old from the initial activation, the chirping will never go away, and it's an indicator to replace the unit altogether.

All detectors (LP, CO, smoke)have a service life and some, as you indicate will warn you when they reach it.

CarpFishermanAndWife wrote:

Allworth wrote:
There are two different things being discussed here:

First....Life Safety Detectors. Checking for things that can kill you.

1. Smoke detector. Mounted near the ceiling at the highest point. Looking for fire/smoke. The danger is obvious.

2. LP detector. Mounted near the floor, usually in the kitchen area. Looking for Propane. The danger is explosion.

3. CO detector. Usually mounted high in the wall in the bedroom. Looking for Carbon Monoxide, a clear, odorless, deadly gas that is a bi-product of combustion (either flames or gas/propane engines such as generators). Danger is suffocation.

The smoke detector is usually powered by a 9volt battery. The battery should be changed twice a year whether the alarm has gone off or not. It is usually recommended that you change it when Daylight Savings Time starts and again when it ends. (You should have these outside each sleeping area in your house. They save lives!)

The other two detectors (LP & CO) are wired directly to the trailer battery. They are so important that you cannot turn them off. They draw a little bit of electricity all of the time. When the trailer is in storage, they will slowly (or maybe not so slowly) run the battery down.


Recharging the battery often is one way to cure this, but the truck is a very poor and slow way to do it. I am lucky and can keep my trailer at the house and plugged in. Obviously this is not an option for you.

That brings up the second subject:

You can keep the battery from being run down by unhooking it completely from the trailer's electrical system using either a disconnect switch or by "pulling" the Negative connection.

A disconnect switch does just what the name implies. Turning it to the OFF position creates a gap in the wire between the battery and the trailer. No electricity can flow. Many trailers are equipped with a disconnect from the factory. It is usually (not always) near the battery and may look like a small lever or key. The dealer should have shown you this if you have one. Auto parts stores sell switches that can be mounted on the battery post.

The second method of creating an air gap is to unclamp the wire at the Negative post of the battery and move the cable aside. Again, no electricity can flow. (The battery should be fully charged before it is disconnected in storage.)


This post has ended up much too long, but I think we were creating more confusion than information and I hope this helped.

By the way, it sounds like your dealer did a really poor job of Pre-Delivery Inspection and training.

Thank you so much for explaining this. It has really helped!

Just a little clarification here, not ALL CO detectors are hard wired!. Some use disposable batteries like the smoke dectector, like mine.

CarpFishermanAndWife wrote:
Ok, what is the difference between installing a battery disconnect switch and just disconnecting the negtive as one poster said? Remember, you are talking to the wife and not hubby so I don't know these things. LOL!

Ease. One requires a wrench, the other just requires you to push a button. Both disconnect one side of the battery.

We're currently fixing up a popup camper. We had an extra used CO detector, put new batteries in it, then attached it near the furnace in the camper. Within a week, it started to chirp every 30 seconds. The propane tank hadn't been connected yet and all the screens were open. Hmm. Put new batteries in again. Same thing.

The fine print on the detector explains that once it reaches 7 years old from the initial activation, the chirping will never go away, and it's an indicator to replace the unit altogether.

CarpFishermanAndWife wrote:


Ok, what is the difference between installing a battery disconnect switch and just disconnecting the negtive as one poster said? Remember, you are talking to the wife and not hubby so I don't know these things. LOL!

No real difference. Disconnect the RV battery, do NOT disconnect the CO or LP detectors.

Allworth wrote:
There are two different things being discussed here:

First....Life Safety Detectors. Checking for things that can kill you.

1. Smoke detector. Mounted near the ceiling at the highest point. Looking for fire/smoke. The danger is obvious.

2. LP detector. Mounted near the floor, usually in the kitchen area. Looking for Propane. The danger is explosion.

3. CO detector. Usually mounted high in the wall in the bedroom. Looking for Carbon Monoxide, a clear, odorless, deadly gas that is a bi-product of combustion (either flames or gas/propane engines such as generators). Danger is suffocation.

The smoke detector is usually powered by a 9volt battery. The battery should be changed twice a year whether the alarm has gone off or not. It is usually recommended that you change it when Daylight Savings Time starts and again when it ends. (You should have these outside each sleeping area in your house. They save lives!)

The other two detectors (LP & CO) are wired directly to the trailer battery. They are so important that you cannot turn them off. They draw a little bit of electricity all of the time. When the trailer is in storage, they will slowly (or maybe not so slowly) run the battery down.


Recharging the battery often is one way to cure this, but the truck is a very poor and slow way to do it. I am lucky and can keep my trailer at the house and plugged in. Obviously this is not an option for you.

That brings up the second subject:

You can keep the battery from being run down by unhooking it completely from the trailer's electrical system using either a disconnect switch or by "pulling" the Negative connection.

A disconnect switch does just what the name implies. Turning it to the OFF position creates a gap in the wire between the battery and the trailer. No electricity can flow. Many trailers are equipped with a disconnect from the factory. It is usually (not always) near the battery and may look like a small lever or key. The dealer should have shown you this if you have one. Auto parts stores sell switches that can be mounted on the battery post.

The second method of creating an air gap is to unclamp the wire at the Negative post of the battery and move the cable aside. Again, no electricity can flow. (The battery should be fully charged before it is disconnected in storage.)


This post has ended up much too long, but I think we were creating more confusion than information and I hope this helped.

By the way, it sounds like your dealer did a really poor job of Pre-Delivery Inspection and training.

Thank you so much for explaining this. It has really helped!

There are two different things being discussed here:

First....Life Safety Detectors. Checking for things that can kill you.

1. Smoke detector. Mounted near the ceiling at the highest point. Looking for fire/smoke. The danger is obvious.

2. LP detector. Mounted near the floor, usually in the kitchen area. Looking for Propane. The danger is explosion.

3. CO detector. Usually mounted high in the wall in the bedroom. Looking for Carbon Monoxide, a clear, odorless, deadly gas that is a bi-product of combustion (either flames or gas/propane engines such as generators). Danger is suffocation.

The smoke detector is usually powered by a 9volt battery. The battery should be changed twice a year whether the alarm has gone off or not. It is usually recommended that you change it when Daylight Savings Time starts and again when it ends. (You should have these outside each sleeping area in your house. They save lives!)

The other two detectors (LP & CO) are wired directly to the trailer battery. They are so important that you cannot turn them off. They draw a little bit of electricity all of the time. When the trailer is in storage, they will slowly (or maybe not so slowly) run the battery down.


Recharging the battery often is one way to cure this, but the truck is a very poor and slow way to do it. I am lucky and can keep my trailer at the house and plugged in. Obviously this is not an option for you.

That brings up the second subject:

You can keep the battery from being run down by unhooking it completely from the trailer's electrical system using either a disconnect switch or by "pulling" the Negative connection.

A disconnect switch does just what the name implies. Turning it to the OFF position creates a gap in the wire between the battery and the trailer. No electricity can flow. Many trailers are equipped with a disconnect from the factory. It is usually (not always) near the battery and may look like a small lever or key. The dealer should have shown you this if you have one. Auto parts stores sell switches that can be mounted on the battery post.

The second method of creating an air gap is to unclamp the wire at the Negative post of the battery and move the cable aside. Again, no electricity can flow. (The battery should be fully charged before it is disconnected in storage.)


This post has ended up much too long, but I think we were creating more confusion than information and I hope this helped.

By the way, it sounds like your dealer did a really poor job of Pre-Delivery Inspection and training.