12V DC timer project

samuel
samuel Solar Expert Posts: 80 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
I'm searching for a way to save some Ah when I'm not around. My family's cabin is off the grid and we like to leave a few lights on when we're gone because when we arrive after dark it's nice to have a few lights ready and waiting for us (It's never fun to try and find a keyhole in the dark) and also to deter a few folks from getting too curious while we are away.

I'd like to find a DC timer to link all of the 12V LED lights to so they run only when nighttime. I found this timer from our host and it looks like it will do: http://www.solar-electric.com/fldctico.html I like that it is programmable, but I'm wondering if there is anything else out there that will automatically adjust as the days get longer or shorter (though not a neccessity).

And also, before I go ahead and start cutting wires and spending more money I thought I'd run it by the knowledable folks on this forum. What I want to do is to connect the following like so:

battery --> fuse (on + line) --> DC timer --> main 12V DC line (which connects to a motion light, two exterior LEDs, and a big triple 5.6W LED fixture in the cabin, total of ~ 27W when running, 36W if motion light tripped). Will it work?

System specs (skip to page 3 for the 12V lights): http://offgridcabin.files.wordpress.com/2011/03/cabin-power-system-schematic.pdf

I'm also open to any suggestions about what hours and how long to run the lights - one thought is to leave the motion lights active 24/7 and put the rest on a timer, or to only put the lights in the cabin on a timer - or maybe there is a way to put the cabin lights on a timer and have the outside lights turn on automatically at night. Thanks in advance for you suggestions.
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Comments

  • rgs03833
    rgs03833 Registered Users Posts: 16 ✭
    #2
    Re: 12V DC timer project

    Hi,

    Get a DC Motion Sensor, more info here, please read thread...

    http://forum.solar-electric.com/showthread.php?t=13036
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  • samuel
    samuel Solar Expert Posts: 80 ✭✭✭✭
    #3
    Re: 12V DC timer project

    rgs03833,

    Thanks for the reply! I read that thread prior to posting. A motion sensor is not what I'm looking for, but I did find link to the timer Cariboocoot posted helpful. At this point I'm looking for proof of concept and possibly any info on an auto on/off switch to turn lights on at night (something other than the RAB Stealth 12V motion sensor which has more features than I need and a price point a bit high for this application). My searches are coming up empty... but I'll keep looking.

    And while my diagram doesn't have the plan for the cabin on it - I'll be using 12V RV LED bulbs: http://www.amazon.com/gp/product/B004QZYTCU (wish NAWS had these in their store).
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  • TheBackRoads
    TheBackRoads Solar Expert Posts: 274 ✭✭
    #4
    Re: 12V DC timer project

    Why don't you run a timer for a generic time like 8PM on 6AM off or whatever but on the output (or before) run a photocell with a relay. That seems a bit redundant however vs just using a photocell but would work...

    Great site BTW, enjoyed the read.
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  • samuel
    samuel Solar Expert Posts: 80 ✭✭✭✭
    #5
    Re: 12V DC timer project

    Photocell with relay = perfect. Thanks a ton. Now I know what I'm looking for! I hate when I know what I want but can't come up with the name. When I finish this latest project I'll put together a write up with some pics. ;-)
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  • rgs03833
    rgs03833 Registered Users Posts: 16 ✭
    #6
    Re: 12V DC timer project

    Hi, do you think you can use this?

    KG316T LCD Microcomputer Time Switch Timer Controller DC/AC12V

    Load: Resistive= 25A - Inductive= 20A

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320763247381&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en

    @ $14 not bad!
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  • rgs03833
    rgs03833 Registered Users Posts: 16 ✭
    #7
    Re: 12V DC timer project
    samuel wrote: »
    rgs03833,

    Thanks for the reply! I read that thread prior to posting. A motion sensor is not what I'm looking for, but I did find link to the timer Cariboocoot posted helpful. At this point I'm looking for proof of concept and possibly any info on an auto on/off switch to turn lights on at night (something other than the RAB Stealth 12V motion sensor which has more features than I need and a price point a bit high for this application). My searches are coming up empty... but I'll keep looking.

    And while my diagram doesn't have the plan for the cabin on it - I'll be using 12V RV LED bulbs: http://www.amazon.com/gp/product/B004QZYTCU (wish NAWS had these in their store).

    yw ;)

    Those LED kinda pricey :(. @ $22 a piece DANG, LOL

    I'll stick with the H7 LED's @ $3.45, LOL... I'm CHEAP! I mentioned on my thread...

    Did you find out what are the LUMENs were? Also, you can't use a dimmer on it. The H7 will work even at 9V, for dimmer lights... It will be helpful when you have low voltage drop. Mine stayed on even at 9V :)

    P.S... I love them set up / gadgets you got there, read your site. NICE!!!
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #8
    Re: 12V DC timer project

    Not t be a smart alek, but a flash light, or lighted key chain is pretty cheap,, and doesn't use power 24/7.

    Tony
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #9
    Re: 12V DC timer project

    I was using timers to prioritize chargeing batteries vs. grid tie inverter. I went thru a few timers, my batteries amp hours increased and the timers left the system. keep looking for a better permanant answer, they will go away.
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • samuel
    samuel Solar Expert Posts: 80 ✭✭✭✭
    #10
    Re: 12V DC timer project

    Well, here's what happened:

    I got the lights set up in the cabin and the ol' man has many positive things to say about the set up. What I ended up doing was wiring in an LED fixture using all 120V AC components (switch & fixture) and running it off of 12V. I did use the timer mentioned earlier, and though the timer arrived in the mail from NAWS after I did the install, Dad reported that it was extremely easy to program and wire in. The light is working out so well that it is often being used as the sole light source at night. It is the only light on when watching the evening news or cooking in the kitchen at night. The quality of the light is exceptional; no blues hue, just a pure natural white light. As for the exterior LEDs we have (lower power) - no photocell yet, still on 24/7. Maybe at some point down the road I'll mod them to only turn on at night.

    to recap: the timer works perfectly (highly recommended)
    3x LEDs on for 7-8hr per day
    16.8 Watts and 1200 lumen when on
    ~ 11Ah a day on a 12V system

    head over to this post for the write up: http://offgridcabin.wordpress.com/2011/10/17/led-lights-cabin-install/
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  • MichaelJ
    MichaelJ Registered Users Posts: 23 ✭✭
    #11
    Re: 12V DC timer project

    For your exterior LED's, you could look into the Night Watchman by Flexcharge. 12vdc, very small, relay built in, 10a (120w) load max, and weatherproof.

    Mike
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  • option7
    option7 Registered Users Posts: 1
    #12
    Re: 12V DC timer project

    If you want a simple plug and play option you can use a 12V programmable timer switch which allows you to plug into an auto/truck/boat/RV female cigarette outlet and plug in a standard male cigarette lighter adapter to turn on and off lights or appliances up to a 15amp load.
    There are 12v and 24v models available on eBay if you search "12V Programmable Timer for Road Pro".
    It has 17 programmable on/off settings over 7 days.
    I use mine for turning LED lights on and off in my RV as well as shut off power at night on my Engle high efficiency DC refrigerator/freezer to save energy from midnight to 5am each day to save my batteries from being run down at night.
    I also use it to turn on/off my 12V coffee maker in the morning and my Roadpro 12V oven to prepare pasta, rice, meats & stews for so my lunch or dinner is ready when I get home.
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