# Most efficient 12V lights?



## Wits' End (Jan 10, 2006)

I'm expanding my solar system (this tyme it is really happening  ) to provide better lighting in a work room (about 400W needed if standard incan). As well as some general lighting, hall, bathroom etc.
Right now all lighting is done with kerosene lamps. High power lighting is done, rarely, with an Aladdin (round wick/mantle). So as a family we don't need a lot of light around the house. We are setting up a workroom to have a well lit place to work together. Sewing (treadle), wood work, paperwork, laptop work or whatever.
So what is 'best'?
*LED's? *My wife, and to a lesser extent me, doesn't care for the harshness of the light. Fine for flashlights but not lighting a room. Are the warm white LED's truly warm? Any reasonably priced fixtures that do a mix of colors, to make 'warm'?
*Flourescent or Compact Flourescent* Life, cost, day to day use? Any 'daylight' type available in 12V?
*Halogen* Efficiency? Glare? Danger to children from heat?

Any comments or questions would be welcome. TIA

Anyone know about 
http://www.innovativelight.com/products/index.cfm?categoryid=100
they seem to have some interesting products. Any retailers, of good repute?


----------



## markdi (Jan 11, 2006)

you could go hid 

3200 lumens will cost you about 42 watts


----------



## snakebite (Jan 11, 2006)

lots of different thinlite options.
they are reasonably good dc fluorescents.northern arizona wind and sun is where i get mine.
www.windsun.com iirc


----------



## Wim Hertog (Jan 11, 2006)

Why don't you buy a nice 120V AC inverter for your solar system? High voltage AC is transported much more efficient than low voltage DC (I*I*R = power loss in cables).

benefits of an inverter:

- Less power loss in cables
- More options regarding light sources (just use common 120V CFL's)
- The ballast circuits driving compact fluorescent lamps are more efficient at doing this from a 120V AC source than from a 12V DC source. 

I would definitely go the fluorescent route (CFL or, even better, T-8 or T-6 linear fl). Incandescent (or halogen) is a waste of power and LED's are too expensive to use as a primary light source.

IMHO, 12V light sources are a waste of money and solar power


----------



## jtr1962 (Jan 11, 2006)

Definitely go with standard T8, 4-foot 32 watt tubes since they are very efficient and readily available in many color temperatures. Inverters exist to drive one or two such tubes off 12V. For the lighting levels you're looking for, I would suggest using four tubes. Definitely go for the 5000K, high-CRI so-called full spectrum tubes as well. You definitely don't want warm white in a work area as it'll put you to sleep and cause eye strain. Best to go with the closest option we have to artificial sunlight.

Forget LEDs at this point. Too inefficient compared to fluorescent, and lacking in color rendering. Of course, in two or three years that picture could change dramatically. As for halogen or any other form of incandescent, all I can say is that I can't believe in this day and age with all the better general lighting options people even still use them, or would seriously consider them for any new lighting project.


----------



## Wits' End (Jan 11, 2006)

markdi said:


> you could go hid
> 
> 3200 lumens will cost you about 42 watts




:huh::duck: Need sunglasses I think 



Wim Hertog said:


> ....benefits of an inverter:
> 
> - Less power loss in cables
> - More options regarding light sources (just use common 120V CFL's)
> ...



But there are power losses in the inverter also. Would the use of the inverter just to power the lights in this one room offset the loss? We also have to consider long and short term cost. _ Any input here would be welcome_ We will still be using Kerosene for the majority of our lighting. When you are used to lamps you don't need a lot of light. When you need light, you pull out a flashlight 




snakebite said:


> lots of different thinlite options.
> they are reasonably good dc fluorescents.northern arizona wind and sun is where i get mine.
> www.windsun.com iirc



Nice site. So the thinlite fixtures take standard bulbs and we can choose our color? Any thoughts on the efficiency of using several of these rather than an inverter and standard fixtures?




jtr1962 said:


> Definitely go with standard T8, 4-foot 32 watt tubes since they are very efficient and readily available in many color temperatures. Inverters exist to drive one or two such tubes off 12V. [highlight][a small efficient inverter?] [/highlight]For the lighting levels you're looking for, I would suggest using four tubes. [highlight] [I was thinking 2 2 tube fixtures for general light and some task lighting][/highlight] Definitely go for the 5000K, high-CRI so-called full spectrum tubes as well. You definitely don't want warm white in a work area as it'll put you to sleep and cause eye strain. Best to go with the closest option we have to artificial sunlight.
> 
> Forget LEDs at this point. Too inefficient compared to fluorescent, and lacking in color rendering.[highlight] [So what about LED's for, what most people would think of as night lights?] [/highlight] Of course, in two or three years that picture could change dramatically. As for halogen or any other form of incandescent, all I can say is that I can't believe in this day and age with all the better general lighting options people even still use them, or would seriously consider them for any new lighting project.[highlight] I was thinking that but thought halogen was pretty efficient[/highlight]


----------



## JimH (Jan 11, 2006)

Order of efficiency from least to most:

Incandescent -> Flourescent -> LED -> HID

If 3200 lumens is to much light, you could use one or two of these. They come in spot and flood, and bounced off a white ceiling will make a very nice area light. Color temp could be adjusted with filters.


----------



## jtr1962 (Jan 11, 2006)

Wits' End said:


> a small efficient inverter?



Yes, they do exist for 12V. Here looks like a good place to start looking. I have one of their 12V ballasts designed to drive a single 32W T8 tube which I ended up with while working on my taxi light project. It draws about 2.85A at 12V while driving the tube to about the same level as a standard 120VAC ballast. I don't really know where to buy these, though. A place dealing in retrofits for vans and RVs might be a good place to start.





> So what about LED's for, what most people would think of as night lights?



LEDs are great for small lighting tasks, basically anything up to a few hundred, perhaps even 1000 lumens. Right now though I wouldn't use them to light a room since the best fluorescents are maybe twice as efficient. If you really want to use LEDs, you could use about 150 or so of Cree's best 1 watt LEDs to give you about the same light as 400 watts of incandescent. You'll be using maybe 180 watts with driver losses and getting about 9000 lumens. T8 fluoro will get you those same 9000 lumens, with better color rendering, using maybe 100 watts. The LEDs will also cost a lot more than the fluorescent.



> I was thinking that but thought halogen was pretty efficient.


Typical 12V halogen can be up to about 25 lm/W. I've heard figures as high as 38 lm/W for special bulbs with a coating to reflect back infrared. Right now run of the mill power LEDs are right around 40 lm/W, the best ones are approaching 60 lm/W, and T8 fluorescent can be around 90 to 100 lm/W. Putting aside color temperature and lifetime concerns, halogen will consume 3 to 4 times the power of a good fluorescent solution plus present a greater fire hazard.


----------



## Wim Hertog (Jan 11, 2006)

Wits' End said:


> But there are power losses in the inverter also. Would the use of the inverter just to power the lights in this one room offset the loss? We also have to consider long and short term cost.




Modified sinewave inverters are dirt cheap these days. have a look at ebay: http://cgi.ebay.com/NEW-400-800-wat...851066609QQcategoryZ79816QQrdZ1QQcmdZViewItem

I think all this 12V gear is much more expensive than a simple inverter. 
Efficiency is between 85-95 percent, depending on the load. The efficiency of 12V fluorescent ballasts and 12V CFL ballasts is 75-80 percent.

Remember to place the inverter close to your battery bank and keep the high current 12V cables as short as possible.




Wits' End said:


> Nice site. So the thinlite fixtures take standard bulbs and we can choose our color? Any thoughts on the efficiency of using several of these rather than an inverter and standard fixtures?



An inverter should be a bit more efficient...and it's cheaper + you have a much better selection of light sources.


----------



## EtdBob (Jan 11, 2006)

Howdy Wits' End!
Like you I live off grid. My wife and I moved up into the woods in '98 and built ourselves a straw bale cottage.

I got a 480 watt solar array and a small windmill, but short winter days, fog, snow, and cloudy weather mean that we go through about five gallons of kerosean every winter!
Right now the wife is hoarding every amp for her sewing machine - She's on a quilting kick again....

Anyway, we use the 30 watt thin-lite fixtures. We have a total of four, and have them mounted on the ceilings of the kitchen, bathroom, bedroom loft, and the spare loft used for hobbies.
They provide fantastic light!
It helps that we have an open floorplan and the walls are whitewashed a pure white. Even when the batteries run low it is sure nice to turn one on for a little while when cooking or doing dishes and whatnot.

The high frequency DC ballasts mean no flicker that can drive ya nuts with AC flourecents.

They are rated at 30 watts, but actually draw only 2 amps on my system.
Bulbs used are standard 15 watt tubes availible anywhere - Which is a good thing. 

If you use an inverter to run AC lights you will indeed complicate the system and loose a little efficency.

I had an expensive Trace inverter that fuzzed after three years of very intermittent use - ( Yes, it was indoors close to the battery box and well ventilated ) and Trace would not help me with a repair at all. I'll never use 'em again.
If my lights were depended upon an inverter I'd be in the dark!
Remember the KISS principal!!

My cottage is wired with 10 AWG romex. From the switch box, I run 14 AWG two wire lampcord up the the light. I don't have trouble with voltage drop.

I have added a few small LED reading lights and a single 15 watt edison base DC flourecent over the years, but I have found the thinlite is the best cost effective deal for DC lighting.
- Bob


----------



## snakebite (Jan 11, 2006)

as for the thinlites i have 8 of them here.
i run ge chroma 50,vitalite,and phillips 950 tubes.
i bought a bunch of the ballasts on sale and retrofitted desk lamps and other fixtures.
i stumbled into several hundred 24v ballasts and have plenty to trade.
might be easier to buy the thinlites if you are not handy.
for simple lighting forget the inverter.
too expensive for a good one and losses would be high converting solar to ac and the ballast converting to hf ac.
if you have panels that natively make 24v you might go that route.less wire losses.
on my 24v side i put 4 of these 24v ballasts in a 2x4 troffer.
if i didnt tell you it was on the dc side you wouldnt know.instant start and no flicker.
and it uses standard f32t8/950 tubes .


----------



## snakebite (Jan 12, 2006)

here is the store url
http://store.solar-electric.com/


----------



## snakebite (Jan 12, 2006)

EtdBob said:


> Howdy Wits' End!
> Like you I live off grid. My wife and I moved up into the woods in '98 and built ourselves a straw bale cottage.
> 
> I got a 480 watt solar array and a small windmill, but short winter days, fog, snow, and cloudy weather mean that we go through about five gallons of kerosean every winter!
> ...



i would use romex for the entire run to the fixture.lamp cord is definately not code for such use.  
for nightlights put 3 white leds in series with a 330-1k resistor and connect across the thinlites switch.
or a pot and 330-470 ohm as a high limit and dial it down if you want.i use 10k and they have a switch for total off.small enough to install in the end of the fixture.


----------



## Wits' End (Jan 12, 2006)

My old system was 12v 110W panel-12v charge controller-1 deep cycle battery.
New is still being finalized but looking at
2 24v 170 watt panels (48v)-charge controller(48) convert to 12 Charge batteries (4 Golf Cart style batteries) Like I said still in the working out. I'm thinking if my biggest user is going to be the lights maybe I should keep a 24v tap someplace. I'll talk to the guy I'm working with as far as the Charge controller area. There are all sorts of options there :shakehead: :thinking:
But keeping eveything after the controller at 12V appeals to the stupid one here in the KISS.


----------



## EtdBob (Jan 12, 2006)

:huh2: Ah, *NO.*
Don't do that. If you have a 48 volt system and controller, use a 48 volt battery pack. That's four 12 batts in series, or eight six volt bats.

Your gonna get such a low efficency by converting after a controller and before the battery bank it ain't funny!

Also, how the heck is the charge controller supposed to sense the battery voltage and regulate the charge?

Then run a 48 volt inverter ( Expensive!!! ) or use DC/DC converters to drop the voltage for DC loads.

Going to 48volts really really complicates things and makes it expensive.
The only reason to do so is to drop wire size! 

Why oh why use 48 or even 24 volts on such a small system????

ONLY do this if your panels are hundreds of feet from the battery bank, or you have big loads far away to run!!!

Dude, I'd say someone has been feeding you a line...
Better go to backwoods solar and do some homework!

http://www.backwoossolar.com/

I'd keep everything 12V all the way! Unless you really do have a long way to go.
For a charge controller, I'd recomend a Morningstar Prostar 30.
They are the only ones I use.


----------



## brickbat (Jan 12, 2006)

JimH said:


> Order of efficiency from least to most:
> 
> Incandescent -> Flourescent -> LED -> HID



Not necessarily so. If I had to generalize on light sources I'd put them this way:

Incandescent - halogen - LED - compact fluorescent - HID (ceramic metal halide) - T8 Fluorescent


----------

