Adding On / OFF swich to CO / Propane detector?

[GDHoffman]

I am about to wire in a 'Safe T Alert' Dual CO and Propane Gas detector into our Scamp 12V circuit. This very expensive detector ($127.89) is only good for 5 years, and flashing lights and beeps alert you when you exceed that time limit. It can be reset for a short interval



Since we only use the Scamp 6 to 8 weeks a year, does anyone know what would happen if I wired in an on/off switch so the unit has power only when we are using the trailer? Could I extend the 5 year "warrantied" life of this detector if I only have it on when we are on a trailer trip? How does the unit know when 5 years are up?


I know having a separate on/off switch circumvents the rationale for the current requirement that CO detectors be wired into the 12V system so they are on all the time. But turning the CO & gas detector on when we start off on a trip is a very small part of getting ready to head off on a RV trip, so I just add it to the TO Do before leaving list, like checking tire pressure.



Is there anything else I need to consider?


George

[AC0GV]

Originally Posted by GDHoffman

Since we only use the Scamp 6 to 8 weeks a year, does anyone know what would happen if I wired in an on/off switch so the unit has power only when we are using the trailer? Could I extend the 5 year "warrantied" life of this detector if I only have it on when we are on a trailer trip? How does the unit know when 5 years are up?

When Scamp sells a new unit it comes with a fuse dedicated for the detector and that fuse is pulled for storage.

Also, shutting off the power will not make the sensor last longer, it will still "age" out.

[ShelbyM]

I don't know how the sensor ages but I pull the fuse when not in use. It's a significant battery drain. A switch would be easier....

[thrifty bill]

On a safety device like that, I would be surprised if any manufacturer would add a switch. A switch means it could be left turned off by mistake and if something bad happened, I can imagine a lawsuit against the manufacturer at that point.

Typically you can add an inline switch in the power line, whether you should is up to you. I understand the battery drain concern.

[Jon in AZ]

My Class B has a battery shut-off supplied by the manufacturer. It disconnects the safety detectors along with everything else. That might be a better solution. Rather than separate switches for every appliance, one master switch to isolate the battery in storage. Some 12V charging stations, system monitors, and newer appliances also have always-on electronic circuits with parasitic drains. As said, it will not extend the life of the sensors, but it will prevent battery drain in long-term storage.

A battery shut-off is harder to forget to turn back on because nothing else works, either.

There are simple mechanical switches you can install right at the battery.

[Casita Greg]

By Code, they are required to be directly hard-wired to the main DC distribution panel, with NO switch or on a ground fault protected circuit, or by any other means of disconnection other than the fuse itself. And although another fuse may sometimes be installed in the power feed, ideally you want that wiring to be protected by a fuse at its source, (in the panel,) rather than way off at the appliance. Further it is only allowed to be wired to either the 12 vdc Main fuse, or a lighting circuit fuse for a circuit that would normally be energized whenever the trailer or RV is occupied. This is to preclude the intentional or inadvertent disconnection of these life safety features while it is being occupied.

And, as was mentioned above, turning it off doesn't buy you any more time with it. It starts aging from day 1, and whether or not it is on, it still will die of old age at the same date it would being continuously on, so no gain there either.

And a simple battery isolation switch will turn off all the trailer's 12 VDC loads and prevent those "parasitic" current robbers from running your battery down while in storage, (assuming you're not on shore power,) which then would also require turning off the Converter's 120VAC breaker as well, otherwise it will continue to make 12 VDC power from your shore power if it is on.

[gordon2]

Originally Posted by Jon in AZ

My Class B has a battery shut-off supplied by the manufacturer. It disconnects the safety detectors along with everything else. That might be a better solution. Rather than separate switches for every appliance, one master switch to isolate the battery. Some 12V outlets, system monitors, and newer appliances also have always-on electronic circuits with parasitic drains.

+1 Or maybe +100 or 1,000

Use a master battery switch that disconnects the battery from everything in the camper. It will not only prevent the battery from slow discharge by the alarm or other things, it will make things a little safer if the battery is disconnected when not needed.

IDK if it will extend the alarm life or not. Mine is disconnected when I flip the (owner added) master switch off, so check with me in 3 more years.

[AC0GV]

Originally Posted by GDHoffman

I am about to wire in a 'Safe T Alert' Dual CO and Propane Gas detector into our Scamp 12V circuit. This very expensive detector ($127.89) is only good for 5 years, and flashing lights and beeps alert you when you exceed that time limit. It can be reset for a short interval


George

My Attwood 36681 draws 0.01 amps (almost nothing) and costs about $100 on line. If you are draining the battery, there may be other phantom loads also.

Don't forget, you want a Dual LP and CO alarm.
P.S.; I just noticed that the detector in my 2017 Scamp is a 2015 device.

[CharlesinGA]

The Safe-T-alert model 35-742BR dual LP/CO detector is $68 from Amazon. This is the flush mount model which is much nicer than the surface mount, but more expensive. I just installed one. Not sure where you found one for over $100, that was highway robbery.

The white one is $66 and the black one is $73, mine is brown. The surface mount models are only about $55.

Since my First Alert ceiling mount battery powered smoke detector also was aged out, I bought an identical First Alert unit but a combo smoke/CO that even fit the original mounting base, for $37 from Amazon. Model SCO5CN. It is NOT a 120v as the Amazon specs imply.

No matter which you buy they all have the same inner workings, just different housings/mountings. Mine was surface mounted on the end of a dinette with thin plywood finish. I measured and marked and used a box cutter to cut the plywood to make a perfect opening for the flush unit. Less likely to get damaged than one that sticks out.

Not trying to make you feel bad or anything, but everyone needs to shop around, it's too easy with the internet. Amazon is almost always close to the best price when you factor shipping in, certainly good for establishing a fair price.

Charles

[computerspook]

That means like $20 a year. For the safety I would not be trying to jury rig it.

[gordon2]

Originally Posted by GDHoffman

... Could I extend the 5 year "warrantied" life of this detector if I only have it on when we are on a trailer trip? How does the unit know when 5 years are up?
...

Cross referenced to https://www.fiberglassrv.com/forums/...ase-91589.html

Originally Posted by gordon2

This has come up before and I asked this question at that time but never got an answer... so perhaps you can explain:

How does a propane alarm detect that it is at end-of-life? What is the specific technology and how does it function when, for an extended time, there is no power (and no internal back-up battery)?

Apparently the propane alarms used in RV's use an Electrocatalytic detector which is described in detail starting on page 14 of this document.

But I see nothing about how the sensor ages out or how the device detects the age or effectiveness of the sensor or device. It does appear that there is not an internal clock and there is certainly not a GPS receiver to get the date and time. So... "how do it know?"

[Jon in AZ]

In my experience it's a moot point. Detectors begin to behave erratically before any end-of-life indicators give warning. Lots of factors affect sensor life, including dust and other contaminants as well as temperature extremes (at least that's what my owner's manual said). RVs typically experience all of those things in greater measure.

Erratic behavior typically means false alarms. I have read several threads about people having trouble with their detectors alarming randomly. Replacing the detector- often under protest ("it's only X years old")- solves the problem almost every time.

I'm with Ray on this. When in doubt, just replace it.

Installing a master shut-off on the battery to prevent parasitic losses in storage is about saving the battery, not the safety detectors, and it's a sensible idea.

[gordon2]

Originally Posted by Jon in AZ

....
Installing a master shut-off on the battery to prevent parasitic losses in storage is about saving the battery, not the safety detectors, and it's a good idea.

Yes, agreed.. but I still have a curiosity about how the alarms know how old they are. Its a mystery that is driving me insane

[John in Santa Cruz]

Originally Posted by gordon2

Yes, agreed.. but I still have a curiosity about how the alarms know how old they are. Its a mystery that is driving me insane

they have a speck of a mildly radioactive isotope in them. those things have a halflife, maybe in 3 years, 50% of the radioactivity is gone, in 6 years, 75%, etc.

[gordon2]

Originally Posted by John in Santa Cruz

they have a speck of a mildly radioactive isotope in them. those things have a halflife, maybe in 3 years, 50% of the radioactivity is gone, in 6 years, 75%, etc.

Ionization chamber smoke detectors, yes.
CO alarms... no.
Propane Alarms... I am pretty sure they dont. My question was focused on Propane alarms.

[computerspook]

Originally Posted by John in Santa Cruz

they have a speck of a mildly radioactive isotope in them. those things have a halflife, maybe in 3 years, 50% of the radioactivity is gone, in 6 years, 75%, etc.

We are kind of getting away from this technology.

[PaintyLiz]

Please do not add a switch to your LPG / propane detector! Ours saved our life when a knob on the stove got bumped and was just barely on, leaking propane into the trailer. We just pull the main fuse coming off the battery when the camper is in storage, effectively shutting down everything in the camper. Please don't put a disconnect on your detector, it could cost you a loved one.

Liz

[PaintyLiz]

also, I echo the sentiment that you paid way too much!

I have no idea how they know their 'end of life' our last one worked for 9 years, I tested it every triip. It evenutally made an audible alarm to tell us to replace it. It was only supposed to last 5 years, too.

Liz

[k0wtz]

Our Scamp has a 12v fuse at the battery pull the fuse everything is dead!


KISS everytime


bob

[chuck giese]

Originally Posted by AC0GV

My Attwood 36681 draws 0.01 amps (almost nothing) and costs about $100 on line. If you are draining the battery, there may be other phantom loads also.

Don't forget, you want a Dual LP and CO alarm.
P.S.; I just noticed that the detector in my 2017 Scamp is a 2015 device.

Depends on how long you store it. 0.01 amps is `1 amp/hour every 4 days. 6 months storage = 45 amp/hours.