running CFL on solar 12V

al128al128 Solar Expert Posts: 65 ✭✭✭✭
Hi there,

what would be needed to run "regular" (110VAC or euro 230VAC) fluorescent tubes or CF bulbs on 12V?

I keep seeing all those "emergency" lights at homedepot (the ones that turn on automatically when 110VAC fails), which are (unfortunately) running off of 6VDC - AND they have "regular" lighting media.

those lights are pretty cheap (<10 bucks) ... with all the electronics incl. that run the regular media - yet DC ballasts seem to be much more expensive than those lamps ...

any good ideas? ... I might try to hook one of those up to a 12V battery and see if they would work or if the magic smoke comes out somewhere

cheers
al

Comments

  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: running CFL on solar 12V

    Regular, garden variety of CFLs run just fine on any cheap modified sine wave inverter, as well as any sine wave inverter.


    There are 12vdc CFLs out there as well.

    Tony
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: running CFL on solar 12V

    i guess my big question to you is what are you trying to light up? most of those emergency lights are only a charger, battery, and dc light. if you wish to make one because what is available commercially doesn't fit the bill for some reason or another it can be done, but i don't know how the costs will compare between what you build and what's available from the store. for small lights, leds are really nice as they would light up stairs enough so that it could prevent one from killing themselves and the draw is low so it could last quite some time comparitively without the battery going dead. larger areas to be lit or very long time spans needing to be on can be problematic even for some commercial units so can you elaborate somewhat on your needs and circumstances?
  • al128al128 Solar Expert Posts: 65 ✭✭✭✭
    Re: running CFL on solar 12V

    DARN!!!!

    my long winded answer just went into the cyber-nirvana... ;-/

    OK, here the short version:

    I want to hang some 8 lights in my garden. Regular CFLs have around 50Lumens per watt, but SE or DE/TE CFLs have around 70 Lumens per watt.

    but I need a ballast to run those off 12 V (something I just found)

    cbd91550.jpg

    cba39640.jpg

    I want to stay at 12V as I have a Xantrex C12 charger w/ light mgmt.

    sorry for being so shortwinded -- but I am pretty fed up ...


    anyway - any thoughts on my setup? ...

    thx!
    al
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: running CFL on solar 12V

    ok, i see no problem doing that as long as what you site for the cfls and the ballasts suits your needs. you do have to size the batteries and charger of course for you don't want to push the battery below 50% dod. this will depend on how long you intend on running those lights without the input of the utility. the extra lumens will be offset by the inefficiencies of converting it from 120vac to 12vdc and using a battery. most times the garden lights will only need to be backup as most of the light is from the sun unless this is to be indoors.

    this won't be cheap as you already know and i sympathize with you on the long post going by the wayside as i'm not the fastest typer and when i get long-winded the whole post sometimes goes into oblivion unless it is done on word processing first. by then you'll find you'd have to relogin in order to copy and paste the post, but at least you'll still have the content of what you wrote. i usually shorten what i wrote, as you just did, or i forget about posting my responce. i've also hurried to post it and then just go back and add to it as i've done this alot as you'll see at the bottom of many of my posts last edited by niel and when. this is the case in adding this and the last sentence, but i've been known to spell badly at times so i will sometimes touchup my spelling or i try to word something better as an afterthought.
  • BB.BB. Super Moderators, Administrators Posts: 32,804 admin
    Re: running CFL on solar 12V

    Also a comment on lumen levels... Our eyes perceive light on a logarithmic scale... And it boils down to that you can hardly see the difference between 50 lumen vs 100 lumen (a factor of two change)--virtually, the only way to see that "small" of difference is to turn on and off one light, then turn on and off the second--and you will probably see the difference (or not--because CFLs may need to warm up--especially in cool/cold weather).

    A "big" difference is a factor of 10x... The light that is 10x larger will pretty much "bury" the smaller... (example, 100 lumens vs 10 lumens)...

    So--for the two lighting levels--I would just choose the system that makes the most sense to you--the difference between 70 and 50 lumen is pretty much near zero (for human eyes).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: running CFL on solar 12V

    There are a number of direct 12vdc cfls out there. Here is a link to some:http://www.nolico.com/saveenergy/12_volt_marine_cfl.htm

    On the other hand, buying a cheap msw inverter, and then using cheap garden variety (no pun intended!) cfls from Home depot might be way cheaper. The inverter might cost ~$25, the bulbs ~$1.

    Not answering the question about how much battery or panel you need though. As we say, "do the math". Figure your average loads, your desired depth of discharge etc, that will begin to give you battery size, which will tell you how much panel etc.

    Tony
  • al128al128 Solar Expert Posts: 65 ✭✭✭✭
    Re: running CFL on solar 12V
    BB. wrote: »
    Also a comment on lumen levels... Our eyes perceive light on a logarithmic scale... And it boils down to that you can hardly see the difference between 50 lumen vs 100 lumen (a factor of two change)--
    -Bill


    I tend to disagree ...

    I switched a (fairly new, prob. less than 3 months old) 500 Lumen CFL for a 600 Lumen CFL in our bedroom - and the difference was noticable, even to the Mss who asked me if I changed anything with the lights...

    to the other poster:
    I MUST use 12V, as the Xantex c12 has a light management feature (using the PV.-panels as photodiode to determine when its night and day). So sorry, no dice on the cheapish inverter. Also, the c12 allows you to "automatizise" the lights, with determined hrs. of light on after dark. E.g. your lights will come on X hours after dusk... iirc you can even programm something like 4+2 (4 hrs post-dusk AND 2 hrs pre-dawn)


    my current situation is evaluating if I go:

    - SE/TE/DE type of CFL medium (w/ 12v ballast), or
    - directly 12V CFL (E-27 socket).

    Pricewise its pretty much a wash: the socketed ones are around 17 bucks, the 12V ballast is around 14 bucks (+3-4 bucks for the "tube")

    .... however, the SE route does leave me with the option for "regular, off the homedepot shelf" media ... and should put out a bit more of light for the same input (900 lumen vs. 600 lumen @ 13W medium) ... so I am currently leaning a bit towards that solution

    but, I am open to suggestions.

    btw, thx for the good discussion!
    al
  • BB.BB. Super Moderators, Administrators Posts: 32,804 admin
    Re: running CFL on solar 12V

    My guess would be that you are seeing the "color" difference between the two lamps... CFL's have a very wide difference in color rendering among vendors and sizes--and between cold and hot...

    You eyes can function over a range approaching the ratio of 1:100,000,000,000,000 (10^14--from low light levels to light levels high enough to risk eye damage).

    The ratio of 500 lumen to 600 lumen is only 0.83:1 ... Not nearly enough difference for anyone to perceive a difference in illumination vs the 1:10^14 our eyes can "see".

    I have several white LED flashlights (which don't change color rendering index over their mid-range)... And I can select between 0.5 watt and 1.0 watt--and when I do an "A" vs "B" test (switch between the two levels), I can just discern the difference. If I randomly turn the light on to a random power level--I cannot reliably tell which is output is selected.

    Our ears have similar logarithmic response... I have calibrated a hydrophone system for recording dolphins and graphed the results on Log and non-log paper--and when listening to the audio output--the results are very clear. Our ears respond to logarithmic amplitude changes. That is why the typical audio system is calibrated in db (DeciBel or 10log -- 10x log in base 10).

    With CFL's, they output their light in several peaks, instead of a broad range of colors (including UV and Infrared).... By using phosphors to emit light only at specific wave lengths that our eyes are sensitive to--they are more efficient than the typical filament bulb.

    However, because CFL's are not "black body radiators", how our eyes perceive their light is quite interesting...

    The typical old florescent tube lamp did not have much red in its spectrum--and made people look kind of sickly... And if you took a picture (with white balance set to sunlight)--you would get a green hue to the photograph.

    Newer CFL's use three phosphors (or more?) to get more peaks in the visible spectrum to make light that better mimics the sun--which is what we evolved with. However, these phosphors are more expensive--so there is a good chance that the cheaper bulbs will look a bit "strange" when compared with the better and more expensive CFL's (note that pure brightness may not be directly related to price). Obviously efficiency, temperature, frequency of the ballast, physical shape may also play into the apparent brightness equation too.

    So--in the end, there are many reasons why the 600 lumen bulb may look brighter to you than the 500 lumen bulb. But pure wattage may not be one of the reasons.

    In the end, whichever light looks best to you and your significant other is what is most important. For us--my wife pretty much hates CFL's, but likes the ~75% savings in power, and the cooler home on hot summer days/nights. And is able to put up with the poor color rendering and (for some) slow warm-up period. We have a few Halogen filament bulbs scattered around where she just must have better looking light.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrockBrock Solar Expert Posts: 639 ✭✭✭✭
    Re: running CFL on solar 12V

    Where to start with lumens. I guess the short answer is that manufactures tend to over exaggerate their light output and some don’t. I have about a dozen different 13w CF's and they range in brightness from one end to another almost doubling the brightest to the dimmest when metered with a candle power meter.

    So just because one manufacture is saying they have 500 lumen and the next is 600 and you can see an obvious difference, one of them is WAY wrong, because percentage just isn't there. Or as Bill mentioned the color difference is slanting the perceived lumen level.
    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
  • BrockBrock Solar Expert Posts: 639 ✭✭✭✭
    Re: running CFL on solar 12V

    Getting back to the point at hand. You keep mentioning that it needs to run off 12 volts, that’s fine and you keep mentioning using the xantrex C12 as a light controller. If it puts out 12v and is connected directly to the eight 12v CFL’s or to a 12v inverter (12 volts DC to 120 volts AC) that is powering the eight 120v CFL’s there is not much difference. Assuming eight 12v 13w CFL’s, that’s 104 watts and running the eight 120vac CFL’s off an inverter might be 120 watts. Either way you’re looking at about 10 amps on the 12 volt side, can the C12 handle that? I am not familiar with that unit.

    If it were me I would use a cheap inverter and stock 120vac CFL’s. Just buy one of each to try and pick the ones you really like and go with them. It would be far less expensive CFL and wiring wise. If you stick with 12 volt you’re going to need some pretty thick wire, 10 times as thick as you would running the 120vac CFL’s for the same distance. If you "cheat" and use smaller wire you will risk burning out the ballast in the 12v units, or under powering them and burning out the lamps themselves, either way the lumens per watt would drastically fall off unless the wire is sized properly.

    If you are really concerned about lumens per watt and price isn't an issue there are some LED's approaching 100 lumens per watt, but it would be a custom setup.
    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
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: running CFL on solar 12V
    Brock wrote: »
    If you are really concerned about lumens per watt and price isn't an issue there are some LED's approaching 100 lumens per watt, but it would be a custom setup.

    Home Despot is now stocking (in Los Angeles) Phillips MR-16 bulbs, LED, 20 watt equilivent, 5 watts consumed.
    http://www.energyfederation.org/consumer/default.php/cPath/25_173_2325
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
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  • al128al128 Solar Expert Posts: 65 ✭✭✭✭
    Re: running CFL on solar 12V

    thx brock, bill and mike ...

    the c12 is able to deliver a constant 12amp ... so up to 140w should be ok (nice thing is the whole lamp issue is fairly easy "scalable")... I hear you on the cable issue, though
    ;-/


    the big benefit is - as mentioned - by using it I can automatize my lighting needs (lights come on when its getting dark, not at a given hour (which will be way off between summer or winter) ), and it also has a pretty nifty load controller, which helps to avoid chewing up your batt's too much - by disconnecting them at a user-settable voltage...

    most likely I will get some 12V ballasts - and buy 2-3 different brands of media to find out how they perform in real life ... than buying all 8-10 of the best one ...



    one further remark: I guess the whole "reflector" issue of a possible garden-lamp solution will be more important on garden lights than the Lumen number of the actual medium (e.g. there is not much sense in illuminating above in a garden, as this will be "lost light").

    Does anybody have any ideas on reflectors? ... I was thinking about a generic white "dinner-plate-above-the-CFL" kind of reflector - sheds rain and reflects down to the ground... anybody care to share thoughts?


    btw ... will white be better than - say - a (theoretical) mirror reflecting down put above the lamp (I always wondered about that) ????

    again, thx!
    al
  • BrockBrock Solar Expert Posts: 639 ✭✭✭✭
    Re: running CFL on solar 12V

    If you were going with 120v you can get them in wide floor par style lamps, I use them in our ceiling cans; I haven’t seen them in 12v yet. Your idea of a paper (plastic) plate would bounce more light down for sure, and also help defuse it.
    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
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: running CFL on solar 12V

    Every cfl you'd ever want,,, and a bunch you don't: http://www.nolico.com/saveenergy/

    Tony
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