12 V Solar Power

[James]

A few weeks ago I set up my 12V solar power in the apartment where my wife and i will be living for the winter. It is small and portable, a 47 watt panel, a gel cell deep cycle battery, 6 amp charge controller, and a 12 V 11 Watt com. fluor. lamp, and old car stereo. It provides about 50% of our lighting, as we can both read by it at night, and we dont light up the whole house. However I figured it only saved 5$ or so vs. using the 120 V AC power. I am thinking of buying a larger 12 V bulb for another lamp. Also it is probably not up to code, but should not be a fire hazard as there are auto fuses installed. The nice thing is that I can move it wherever I go.

[QDM]

Look out James, that's how it starts. Around 20 years ago I did the same thing, hooking up a single panel to a battery and some lights. Before I knew it I had a full scale system and was off the grid.

Q

[JanGeo]

Gets a bunch of white LED's and save that battery power!!!

[onegammyleg]

Well , yeah , LED's , or he could just read with only 1 eye open.
That must save 50% if my kalkulations are correct. :D

[Brock]

Actually in lumens per watt CF still edges out LED's, but the big advantage of LED's are they put the light where you want it where a CF will throw it in all directions.

[DracoFelis]

Actually in lumens per watt CF still edges out LED's, but the big advantage of LED's are they put the light where you want it where a CF will throw it in all directions.
That used to be true (with the older LED technologies). But I don't think it's true of the newest LED technologies (i.e. the LEDs that have only been out for a year or two).

If I'm correctly remembering the chart I found (on the internet) a while back, most CF are only around 50-60 lumens/watt. While this is still a lot better than incandescent bulbs, some of the latest LEDs (already on the market) are already doing over 90 lumens/watt (close to twice CF's efficiency), and the designers are still working hard to push the efficiency even higher. And that's on top of what you just said about LEDs focusing better (i.e. putting the light exactly where you need it).

OTOH: LEDs aren't yet "cost effective" as primary lighting, as it just costs too much to make a LED module that puts out anywhere near the lumens that most homeowners expect for lighting a room. i.e. it will be much cheaper (from the standpoint of buying the "bulbs") to use CF to light your house, then to use LEDs. And the slight edge that (the newest) LEDs have in power efficiency, is still not enough to overcome their much higher initial expense in most cases (sort of like the early days of CF's, when the CF "bulbs" weren't "cost effective" to use everywhere due to their high initial expense). But for smaller lighting needs (such as small "task lighting"), LEDs already are carving out a nitch for themselves (even around the home). And as the price of LEDs starts going down over time, their practicality as (home) lighting will inch up.

[Brock]

Ok, regular incandescent’s run about 8 lumens per watt, halogen run about 12-15 lumens per watt, cold cathode and LED's typically run about 25 lumens per watt, HID run about 30 lumens per watt, fluorescent’s run about 40 lumens per watt and finally low pressure sodium (orangish street lights) run about 120 lumens per watt.

There are variables in all of these, they recently released a 5 watt LED running about 50 lumens per watt and I also saw a prototype 100w die running about 45%, very nice ;) I have a pretty good inside lead to some of the manufactures and haven't heard of any production LED's over 50 lumens per watt, yet...

One of the neat things about LED's is as the voltage is lowered (thus reducing overall power) to the LED the lumens per watt actually goes up, while halogen and incandescent lamps the lumens per watt drops WAY off. So running a halogen lamp at 50% of its rated wattage will get you about 10% of the light output and running an LED at 50% of its rated wattage will typically net you about 60% of rated light output.

A lumen is a measurement of the total light output.

If you want to know more about LED’s and or flashlights check out http://candlepowerforums.com/ I happen to be an admin over there.

[JanGeo]

LED's just doubled (almost) the light output per watt . . .

http://tech.groups.yahoo.com/group/ETList/message/6480

The other thing about LED lighting is that it doesn't blink like a CF or hum or produce a wicked amount of EMR - some of my old CF bulbs radiate like a bastard. Plus you CAN dim a LED really easy and they run directly on DC vs an inverter for the CF.

[Brock]

That is really weird they have all the numbers I have know about for a couple of years doubled, hummmmm. Either way in that article they say CF are about 80 lumens per watt and the cree is about 70 lumens per watt. Don't get me wrong I really like LED's. I have them in way to many places around our house and in over 200 flashlights I own, but at this time for area lighting CF still seems to be the direction to go.

[Brock]

;) Most don't have the batteries in them, just a few that I regularly use and the ones I have here at work.

[James]

I would like to get an LED bulb, but I think I will wait for a couple years for the price to go down/efficiency to go up. I am using a 12V CF bulb, so no inverter is necessary. I used to read by a 25 watt 12 V incandecent and found it quite bright...also those bulbs are only 2$ as opposed to 12$ for the CF. I may get one of those for a 2nd lamp.

[James]

I also have an LED headlamp. It is a single super bright LED model (about 2yrs old). It is great, it always works, and has yet to run out of batteries. I was thinking about rechargables, but it may be years before my batteries run out.

[JanGeo]

I use a single 9 watt CF for over 10 years now lighting my entire office and it is up high so I don't get any emf from it I used to have two of them but one died. What is really neat is the 26" HDTV on the low power screen brightness setting only uses 55-57 watts and looks great and helps light up the room. The old 13" tube TV used about 60 watts.

[Ryland]

they tend to cost a bit more, but the Luxeon LED's http://www.superbrightleds.com/cgi-bin/store/commerce.cgi?product=CAR
for cars seem like they would be ideal, extreamly bright, I have one of the flashlight 3 watt LED's (two of them now) in my flashlight, and they are brighter then kripton bulbs in a mag light (new bulb, flashlight, and batteries comparied side by side), I also gave a 19 LED white cluster that was made to fit in the back up light socket to a friend who has a cabin and ran it straight off a car battery with no charger for many many months straight.