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Thread: 12V lighting for off-the-grid cabin

  1. #1
    Unenlightened
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    Default 12V lighting for off-the-grid cabin

    Hi everyone,

    i'm building a small off-the-grid cabin with a modest solar PV system, and I'm trying to design an interior lighting system that gives the most light for the fewest watts, and runs at 12V, to avoid needing an inverter.

    The cabin is one 10'x16' room with a loft bed and high (10-14') vaulted ceiling.

    My initial idea was to do a cable lighting system, replacing the MR16 halogens with LEDs. However I'm still looking around for other options.

    Last year I experimented with an automotive-style bulb made of 42 warm white LEDs and found it was not nearly bright enough. After a bit more research it looks like I was naive thinking I could light a large room with a 1.5W lamp.

    After reading some posts on this forum, I'm thinking of trying some 12V bulbs driven by super-bright cool white LEDs (Cree/Luxeon/etc). I can always use candles if I want warmer lighting for a dinner or something. A more realistic energy budget for this system would probably be 15-20W.

    I'm open to any suggestions at all on how to do this better. I'm sure others out there have attempted something similar to this. Any recommendations are appreciated be they general design tips or specific products.

    Thanks in advance!

  2. #2
    Flashaholic* LEDninja's Avatar
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    Default Re: 12V lighting for off-the-grid cabin



    You can get MR16 Cree bulbs though I find the narrow beams a problem. You will need multiple bulbs as a 100W bulb is 1400+ lumens. Your automotive bulb is listed as 115 lumens.

    3x1W US source 200 Lumen (White); 180 Lumen (Warm White)

    3x2W canadian source 300LM(Cool White), 240LM(Warm White)

    3x2W Australian source Warm White 260 lumens
    PM WeLight for more info.

    -

    There are LED linear and flex modules.

    -

    You can build your own LED fixture(s).
    Last edited by LEDninja; 03-16-2010 at 09:34 AM.

  3. #3
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    Default Re: 12V lighting for off-the-grid cabin

    I saw some 12v strip lighting in either (can't remember) Home Depot
    or Rona (both in Canada). It came with its own wall-plug switching
    adaptor.

    Dave
    Last edited by Dave_H; 03-19-2010 at 01:57 PM.

  4. #4

    Default Re: 12V lighting for off-the-grid cabin

    Hi keeth.

    If you aren't worried about making your own fixtures, I'd advise using a Bridgelux BXRA-W0402-00000. I was looking at their LED arrays again, and saw this model on Newark. This one operates on ~6.3W and outputs 460lm of warm white light; roughly speaking, you could fit 3 of these into your energy budget.

    Just for reference (see this thread), this model is roughly equivalent to a 100W lightbulb in its 120 degree throw.

  5. #5
    Flashaholic* Linger's Avatar
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    Default Re: 12V lighting for off-the-grid cabin

    A number of emitters spaced across the ceiling, mount each on a steel plate (size of a CD) for heatsinking.

    *I recommend bringing a desk lamp, a 12v halogen (you could stock 5w and 10 w bulbs). If you lop off the transformer you might be able to feed the 12v circuit right into the lamp cord. After a while the hollow spectrum of LED light gets to me and I forsee you really enjoying the option of %100 CRI at times.

    -a few cree mc-e emitters. The mc-e is 4 dies, emitter can be wired in series. A few parrallel mc-e's along your ceiling would be decent. mc-e's about $12-15 from Cutter. You can get really good colour.
    -Alternately some discount C bin P7's wired in series.
    -Alernately a single CBM-360: 4x luminus ssr-90 dies on one copper chip.
    Installing Quantum Tunneling Composite (QTC) into M@glite Solitare

  6. #6

    Default Re: 12V lighting for off-the-grid cabin

    Howdy!

    10 x 14 ain't that large and is possible to illuminate the way that you are wanting to do - using a small 12-Volt system.

    I have been using a small system for almost 3 years now, and the LED lighting is doable.

    There are a couple of approaches that you could consider...

    1) Using a 12-Volt track-lighting system - modified to use your 12-Volt battery. I used one of those for about 2 years, consisting of 3 MR-16 LED 'bulbs' - that put out about 145 Lumens each, for a total of about 435 Lumens of light. This will light the room, but maybe not be a 'blistering white' light.

    2) As others have mentioned, you can make your own LED lights. That is the direction I am now going, my latest lighttubes put about 500 Lumens in a 6-inch long tube. I will put 4 of these onto my light-tube - for a total of about 2000 Lumens.

    Look up my history of postings to see what I currently have up on the wall, and how it lights up the room. My mobile home is about 16-feet wide and the coverage I am lighting is about 25-feet long.

    Be sure to use an LVD of some sort - to disconnect your battery when it gets discharged - so that you do not destroy the battery.

    If you need more info, contact me, and I may be able to help.

    Regards,

    James Jackson

  7. #7
    Flashaholic* TorchBoy's Avatar
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    Default Re: 12V lighting for off-the-grid cabin

    keeth.

    Quote Originally Posted by Linger View Post
    A number of emitters spaced across the ceiling, mount each on a steel plate (size of a CD) for heatsinking.
    ...
    -a few cree mc-e emitters. The mc-e is 4 dies, emitter can be wired in series.
    I like the steel plate idea but a 12 V battery system is unlikely to have enough voltage for four white LEDs in series.

    A Cree XP-G is the most efficient LED around at the moment; at 1.5 W (like your 42 LED bulb) it produces about 200 lumens. If you want to light up the room reasonably well you'd probably need at least six times that, which you could do with as few as 3 XP-Gs (1.2 A each, total 15 W including 80% driver efficiency), or, say, 8 of them (360 mA each, total 10.5 W including 82.5% driver efficiency) depending on how hard you wanted to run each one. (They get less efficient when run harder.) Either way, it comes in within power budget. You can get heatsinking MR16 housings to put them in.
    No, a torch does not always mean flames.
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  8. #8
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    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by RobertK View Post
    Hi keeth.

    If you aren't worried about making your own fixtures, I'd advise using a Bridgelux BXRA-W0402-00000. I was looking at their LED arrays again, and saw this model on Newark. This one operates on ~6.3W and outputs 460lm of warm white light; roughly speaking, you could fit 3 of these into your energy budget.

    Just for reference (see this thread), this model is roughly equivalent to a 100W lightbulb in its 120 degree throw.
    I second this idea of using bridgelux leds, I have five or so of them and the warm and neutral white ones are extremely bright and put out a nice color.

    3 to 4 of the BRIDGELUX BXRA-N0400-00000 run in parallel should put out plenty of light for a room that size. Plus since they only need like 9-10 volts a piece they would be perfect for your 12VDC supply.

  9. #9
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    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by keeth View Post

    I'm open to any suggestions at all on how to do this better. I'm sure others out there have attempted something similar to this. Any recommendations are appreciated be they general design tips or specific products.

    Thanks in advance!
    You didn't mention overall budget for this project, but it would certainly
    help to narrow things down. My experience is rather limited to lighting
    small rooms with individual (including battery-powered) lamps that
    would not likely be practical to you. I have yet to build custom
    lighting but will take the dive sooner or later (hopefully sooner)

    Meantime, I have found a commercial 120v 2W LED bulb (Sylvania)
    which lights my upstairs hall to a nice warm light; not too bright
    but very good dispersion. It costs $10. You may find a 12v equivalent
    somewhere. A simple solution would involve finding suitable fixtures
    and wiring them up.

    True experts have more ideas about mixing different LED colours
    etc. which is fine but tends to complicate the design.

    Dave

  10. #10

    Default Re: 12V lighting for off-the-grid cabin

    In regards to Bridgelux, I'm in the process of building some killer drop rails using the 402s, and not even considering Cree. I need +3000 lumens of light, and only the Bridgelux gets me there with the right budget and flexibility. They also just got their energy star cert on the ES line.

    However, I would NOT use Bridgelux for this project. Main reason is that their warm-whites are very inefficient and not the ideal match for a battery anything. They look awesome and have a superb lumen to price ratio, but they are dogs on efficiency. The Bridgelux cool whites are better in this respect.

    Also, the only way to work a Bridgelux in a 12volt circuit is to either waste power with a resistor, or you'll need a 500ma buck. It's easy to do, but another problem is you then have a lot of light coming from a single spot in a small area. You have no idea how bright a 450lumen emitter is stuffed in a corner and how obnoxious it it.

    My advice for the OP is his original idea, and that's to use higher quality Cree based 12volt MR-16s. These will get you the best efficiency and color with the least screwing around. If you go DIY, I would just bolt some neutral Crees to some Alu bar and run it off a 700mA buck.

  11. #11
    Flashaholic* TorchBoy's Avatar
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    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by blasterman View Post
    ... another problem is you then have a lot of light coming from a single spot in a small area. You have no idea how bright a 450lumen emitter is stuffed in a corner and how obnoxious it it.
    It's incredibly harsh. How optically efficient is the prismatic plastic that's used for fluoro tube fittings?

    Some wonderfully diverse ideas in this thread. I like.
    No, a torch does not always mean flames.
    Ian.
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  12. #12

    Default Re: 12V lighting for off-the-grid cabin

    Very efficient. Over 90%, but it only works mediocre on small point sources like LEDs, but better than nothing.

  13. #13
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    Default Re: 12V lighting for off-the-grid cabin

    welcome to cpf.


    you could hang some LED lanterns ( 8-D cell type ) with wiring to the battery system.

    benefit would be the dual-use ability: wired into cabin power with no batteries internally, or temporarily stick some D-cells in them and use them outside.

    there are 8-D cell fluorescent lanterns, too.


    also, you could take them with you when you leave.


    http://www.walmart.com/ip/Coleman-Tw...ntern/13849011

    http://www.walmart.com/ip/Coleman-Fa...ntern/13849010

    http://www.walmart.com/ip/Coleman-8-...antern/8223656
    Last edited by watt4; 03-18-2010 at 11:52 PM.

  14. #14
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    Default Re: 12V lighting for off-the-grid cabin

    I had a look at the strip lights at Home Depot. The 12'' 15-LED one
    is $40 (CDN) and runs from AC. Cold white, not very efficient (gets
    pretty warm) for the amount of light output. Disappointing so I
    don't recommend it. Consumption is ~1W.

    The 12v light is a 30-LED (5x6) grid of similar 5mm LEDS, for
    $50. Comsumption rated at 2W. Supplied adaptor is 12v/1A,
    good to power 3 or 4 of these. Not that great either but it's good
    to find out. Must be something better out there for same or less
    money.

    Dave

  15. #15
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    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by blasterman View Post

    My advice for the OP is his original idea, and that's to use higher quality Cree based 12volt MR-16s. .
    Any in particular you can recommend, especially available over the counter
    retail? Don't know about the OP but I'm the type who likes to see stuff
    before I buy it whenever possible.

    Dave

  16. #16

    Default Re: 12V lighting for off-the-grid cabin

    Cutter has some nice MR-16 12-volt retrofits, and they stand by their products.

    The typical 5mm beehive light is pretty much garbage, along with most of low end junk sold at big box stores. A single Cree often puts out more light.

    The cheap_a_zoid way to do this is R2s from DX, a cheap heat sink, and 12volt driver.

  17. #17

    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by blasterman View Post
    In regards to Bridgelux, I'm in the process of building some killer drop rails using the 402s, and not even considering Cree. I need +3000 lumens of light, and only the Bridgelux gets me there with the right budget and flexibility. They also just got their energy star cert on the ES line.

    However, I would NOT use Bridgelux for this project. Main reason is that their warm-whites are very inefficient and not the ideal match for a battery anything. They look awesome and have a superb lumen to price ratio, but they are dogs on efficiency. The Bridgelux cool whites are better in this respect.

    Also, the only way to work a Bridgelux in a 12volt circuit is to either waste power with a resistor, or you'll need a 500ma buck. It's easy to do, but another problem is you then have a lot of light coming from a single spot in a small area. You have no idea how bright a 450lumen emitter is stuffed in a corner and how obnoxious it it.

    My advice for the OP is his original idea, and that's to use higher quality Cree based 12volt MR-16s. These will get you the best efficiency and color with the least screwing around. If you go DIY, I would just bolt some neutral Crees to some Alu bar and run it off a 700mA buck.
    I've got that little 15W flashlight buck/boost converter from DX- I don't know if it goes up to 12V input yet (will have to look to see if anyone tested), but it does pretty darn good with 9V in.

  18. #18

    Default Re: 12V lighting for off-the-grid cabin

    Remember to run your LEDs at lower than max brightness. If you've got everything running right up to the absolute max, you lose a lot of efficiency. Your best bet is going to be well-heatsinked emitters scattered broadly, rather than trying to get a few to put out a lot of light.

    Heat is your enemy here, since it's not light. Minimize your production and save the electrons for lumens.
    EDC E1B, Tigerlight w/LED dropin for when I need more light. Love my new Zebralight H30 for floody tasks and my Quark Mini123 for being awesomely small and bright.

  19. #19
    Flashaholic Light Sabre's Avatar
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    Default Re: 12V lighting for off-the-grid cabin

    You didn't mention what type of batteries you were gonna use in your system I would assume lead-acid. FYI: marine/deep cycle batteries will take running down to lower voltages and will take repeat charge/discharge cycles. Car batteries don't like this type of treatment at all. It dramatically shortens their life span. Don't want ya left in the dark unexpectedly, but I'm sure you would have flashlights and portable lanterns as backups.
    Wrong Planet

  20. #20

    Default Re: 12V lighting for off-the-grid cabin

    I did this as a kid actually! it wasn't a cabin, but a "fort" (thing taj mahal in the trees) we "procured" a car battery and a solar charging system from an automatic deer feeder and we wired up a bunch of LEDs. This was back before high powered LEDs so we were really excited about the white 5mm ones lol. (me and my cousin were the weird kids...but we had the coolest fort!)

    Anyway, the recommendation that I have is to either go indirect, or get diffusers. Harsh glaring doctors office style lights are usually not very "camping site" friendly. I know there are some losses in efficiency, but I would most definitely take those. CREE just announced the most efficient "warm light" ever, so it may be worth checking in to those. If you drive the CREE at 350ma each...heat buildup shouldn't be too bad of an issue. Anyway now that I have typed a lot and said almost nothing...my recommendations are 7-10 CREE, Indirect/diffused, and that should get you a well lit room. "Modular" lighting is always helpful too, build 7-10 fully contained lights (driver, sink, emitter, diffuser) and put them up temporarily and experiment till you find the perfect dispersion and fewest number, and then screw em up and run permanent wires. (run the extra's by the porch, bathroom/port-a-potty, or woodpile.
    Enlightened from birth

  21. #21
    Flashaholic* TorchBoy's Avatar
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    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by SFG2Lman View Post
    I did this as a kid actually! it wasn't a cabin, but a "fort" (thing taj mahal in the trees) ...
    I'm curious - did you have a huge amount of white marble up there or a coffin? Either way, it sounds awesome.
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  22. #22
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    Default Re: 12V lighting for off-the-grid cabin

    Someone above mentioned having low voltage disconnect to keep from over-discharging the battery. That's important as deep discharges reduce the number of discharge cycles a battery will last. There are quite a few charge controllers, including some relatively affordable Morningstar ones, that have a "Load" output on them that can source 12VDC up to 10 amps or so and provide LVD protection for that Load connection. It might not be usable in your situation, but their SunLight models even have customizable lighting programs that uses the power input from the solar panel to queue up dusk to dawn lighting or on-at-sunset for 2 hours, or 4 hours, etc. Could be useful for outdoor or while-you're-away lighting.

  23. #23
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    Default Re: 12V lighting for off-the-grid cabin

    I will admit I skimmed most of the posts so if this was already discussed I apologize.

    I've been running led ligting my house for over a year now and have a small simple system.
    I've had to build all my own fixtures and bulbs. All i've used is 5mm leds. Now i know i could do what i've done with cree's and so on but what i've got works.
    None of my lights are mounted in the ceilings. except for the basment and I've got low 7' ceilings down there. Gettin all the led light down from 10- 14' ceilings just doesn't make all that much sense to me. Yes i'd put flood lights up there to help and throw light down and help light the general area.but i'd rather have task lighting and lights for specific things. I'd rather go with under the counter lights in the kitchen desk and floor lamps for area lighting. llights just above and below the bed since its a loft bed. things like that Bring and put the light where you want it instead of just lighting the whole room with as bright of lights as you can make from the ceiling.
    Also throw in some icans for when you need bright natural light and only use them when needed. you'll appreciate the change in lighting from time to time.

    Just my two sense, take it as you will.

    good luck with the project.
    What we have here is a failure to illuminate.

  24. #24

    Default Re: 12V lighting for off-the-grid cabin

    You could use automotive HID kits. They claim almost 100lm/W. I'm not sure about that, but they can't be too far from an LED's efficiency. Also, 35W worth of LEDs and driver hardware is likely far more costly than 35W worth of automotive HID. They're like $40-50 per pair on ebay, I think.

  25. #25
    Flashaholic* TorchBoy's Avatar
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    Default Re: 12V lighting for off-the-grid cabin

    Quote Originally Posted by Cyparagon View Post
    You could use automotive HID kits. They claim almost 100lm/W.
    Where is that claim made? 3200 lumens is a typical figure, or 91 lm/W. Include ballast efficiency and I don't see anyone being able to claim an automotive HID efficacy of 100 lm/W.
    No, a torch does not always mean flames.
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  26. #26
    Flashaholic jawnn's Avatar
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    Wink2 12volt with edison base

    I set up a track light with these low glare bulbs http://www.ledlight.com/par16-three-1-watt-led-light-12-volt-ac-dc-ncnr.aspx these are very bright, and good for taller ceilings than mine because they are focused with tighter beams. Not so good for swing arm lamps for reading.

    I am still looking for bi-pin fixtures for the track, because I have several of them http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&category=MR16&Page2Disp= %2Fspecs%2FMR16-x48SMD.htm these have good dispersion (like a regular bulb) but shades are needed, like a swing arm lamp. They put out EMF that interferes with my radio. I use one cool and one warm to get neutral light on my drawing board.

    ok even the newest LED I got has some EMF....so I put the antenna put side.

    I just got the brightest light yet: it has a 6watt cree MC-E and lots of thin aluminum fins to sink the heat, and most of it made of plastic rather than the glass (even the difuser lens) or metal of the rest of them, making it lighter weight. Unfortunatly it's twice the price of some of the bipin 3 watt bulbs. But there doesn't seem to be any EMF...

    This is the kind of light I was looking for a year ago. http://www.superbrightleds.com/cgi-b...2FMR16-W6W.htm
    Last edited by jawnn; 11-21-2011 at 12:50 PM. Reason: info

  27. #27
    Flashaholic jawnn's Avatar
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    Default Trak Fixtures for LED lights

    some MR16 bi pin trak fixtures
    http://www.lightingfx.com/search.asp...6%2C&search=GO

    I got a new one that is realy bright
    http://www.superbrightleds.com/cgi-b...2FMR16-W6W.htm

  28. #28
    Flashaholic* Samy's Avatar
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    Default Re: Trak Fixtures for LED lights

    I use a 5 metre strip of waterproof "5050" Warm White led lights when camping. I purchased it from Ebay for about $40. It has 60 led's per metre and is cuttable every 3 LED's so you make your own lengths. It is VERY bright, possibly too bright for camping as i have other campers come over to me and say "WHOA!! What are you using!?" It uses 2.6 amps for the whole 5 metres and i run them (and other items) from a deep cycle lead acid car/marine battery and charge the battery during the day with a 60w folding solar panel kit. This photo does not do the strip justice, it is much brighter:






    This year i will be purchasing more solar panels, batteries & gear and this "5050" led lighting and setting up some 12v lighting in my garage and garden sheds at home. When that is successful i will be rigging up similar lighting around the house for exterior lighting, all to be run from solar. My solar regular i use can be set to automatically turn on the lights when the sun goes down for a set length of time, which will be good when we're away from home.

    cheers

  29. #29
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    Default Re: Trak Fixtures for LED lights

    OK, I know the last reply was some time ago, but I would suggest a simple 12 volt 15/24 watt CFL in about the 4,000K color temp range.

    I have the 12 volt 15 watt CFL in a lamp in my living room that gets the most use and is positioned at the base of the stairs going upstairs. It is powered by a deep cycle battery in the basement bulkhead via a fused circuit. The battery is charged via a charge controller by a 45 watts PV array outside. It is obviously a costly method of providing light given the fact I do have grid power, but I like the fact that I have a charged 12 volt battery in the basement ready to go. The neat part was that the lights went out a few months ago and this light stayed on (of course) and provided the bulk of our needed illumination downstairs.
    Thanks,
    Brian

    Many, many, many lights... I need a 12 step program for my "illness"!

  30. #30

    Default Re: Trak Fixtures for LED lights

    I made my own lights for a cabin.
    I used a great big heat sink 4x4x3 with thermal controlled fan
    then a 700 lumen bridgelux surrounded by 3 ea. 180 lumen cree,
    on-off + dimmer on bridgelux and on-off on the crees (2 circuits)

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