12V smoke detector

We (Colorado Mtn Club) have a high mtn cabin with a 12V PV
light system. We currently have battery smoke detectors, but
can't count on them since various folks use the cabin and
don't check them, don't put a battery in, etc, etc.

If we had a 12V smoke detector wired in, it would come "on"
when the master light switch is turned "on"--so would be just
right--"on" when the cabin is being used and "off" otherwise.

I find 12V detectors for commercial installations with control
by a 12V fire panel (System Sensor i3, for example) but nothing
I can use. Plus, nothing turns up in a search of the forums on
this site.

Are there 12V detectors? Am I missing something? Thanks for
any information or direction.

Richard Jones
Boulder, Colorado


  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    Re: 12V smoke detector

    I know some of the boats I used to move had 12v wired detectors for both smoke and flammable gas. I would try looking at marine or RV supply places.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: 12V smoke detector

    My first thought was a MorningStar 300W SureSine inverter

    and run a $15 conventional 120V powered alarm.

    but it needs an 8 Watt load to stay on, else it shuts off.

    My next thought is a 12VDC - 9VDC switching converter module to use a standard $5 smoke alarm.

    Digikey has a $13 one, but you have to make a little circuit board for it.
    it does have a large MTBF >1,000,000 hrs
    Digi-Key Part Number 102-1510-ND Manufacturer Part Number VWRBS2-D12-S9-SIP
    79% efficient. Description CONVERTER DC/DC 9V OUT 2W

    2W should power a smoke alarm.

    "Lifetime" reliability is a concern, as this is a safety item, and this homebrew approach works fine on paper.
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    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    Re: 12V smoke detector

    I would go with this, est. live is 10 years.


    I did the 12v to 9v regulator for mine, but also added a light to each detector to verified the they where powered.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: 12V smoke detector

    i would debate the practicallity of putting a smoke detector on the master light switch for when the light is off, for say some to sleep, a fire could breakout or even get a backdraft from the fireplace chimney bringing in the smoke.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: 12V smoke detector

    I suggest that you could buy a 9vdc $5 detector, wire it direct to a 12 volt battery and I bet it would work just fine. Some electronics will run fine on voltages out of their basic design. ( I wouldn't try this with anything expensive however)

    Good luck.

  • System2
    System2 Posts: 6,290 admin
    Re: 12V smoke detector

    Thanks for the comments and ideas. I looked at RV and marine sites and
    have not found any 12V detectors--ok, maybe at $145.... They like to
    wire-in propane detectors, etc, but seem to just use battery smoke

    When I say "master light switch" I mean a cutoff. So the switch is "on"
    when the cabin is occupied and "off" otherwise, so it would be a good
    place to control a detector, at least on first thought.

    Maybe I will try a cheap 9V battery detector wired to the 12V system!

    But, reading about detectors, I see they all have an operating temp
    range of 40F on up. Both kinds of detectors have trouble with
    condensation, so the makers don't want deal with colder temps and
    changes. But that is just what we have--cold, unoccupied cabin
    to warm cabin.

    I have to back up from "12V smoke detector" to "ice cold smoke
    detector" and research this more. ;-)

    I'm wondering now if we can even have a reliable detector for
    the cabin when we can't assume any competence from the typical
    cabin users, or ability or willingness to read and follow some simple

    Anyway, thanks for ideas and comments!

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: 12V smoke detector

    Rich, I installed a double throw 'disconnect' in my cabin.... want lights, pull master switch

    this might be a way to ensure the power 'flows' to your smoke detector, if you took a tap off at a 'master switch'. If they want lights the detector will be powered.

    Just a thought...

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  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    Re: 12V smoke detector

    I like the idea of a 12v to 9v converter. I forgot I had one of those in our last house for the cordless phones. The wall wart used 4w 24x7 using the phone or not. I pulled that and put in 12vdc to 9vdc adapter from RadioShack and it was pulling 60mA at 12v or .75w. I had it that way for about 3 years without any problems. I never thought of hooking it straight up to 12v.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI