Learn from Experience!My own experience happened fairly recently. When Hurricane Ike visited Houston in 2008, the impact was tremendous because of the loss of power. Even though my power was off for only 3 days, I lost all the food in my freezer and refrigerator.
Right across the street and in many, many neighborhoods it was off for 2 weeks, because of the damaged poles and transformers. I understand that they actually ran out of transformers and had to wait for more to be built.
Meanwhile, the lights were off as well. For my own well-being and to keep working, I had to do something to keep some lights on, to be able to use small power tools, recharge my cellphone, run my answering machine, keep cool (with a fan), and therefore keep working at my job at home.
I had a spare car battery that was mostly charged up, and an inverter that created 120 Volts AC from the 12 Volts in my battery. Using that, I powered a fluorescent light. Once I could see to work again, I found my white LED's that I had bought some time ago, and wired them to work on 12 Volts from the same battery, thereby bypassing the inverter and its conversion loss.
Powering LED's from batteries is easy. No voltage conversion, only some current limiting by a single resistor. Look inside an LED flashlight some time to see how simple they are. The newer flashlights now have a tiny switching power supply in them that scours the last bit of energy from your flashlight batteries.
This is the same principle I have used for my Room-Lighting LED Assembly.
So, I am certain that in a world where power can go off for days at a time, a new approach to LED lighting is needed. Every LED bulb sold these days for the home and office has within it what amounts to a whole switching power supply and an LED driver circuit. If you have 10 bulbs, you have 10 individual power supplies.
It is far cheaper to make low-voltage fixtures with a central power supply that runs several LED modules at once, that are NOT located inside the bulb. Heat kills electronics, and some of the newer LED bulbs for 120VAC sockets have tiny air movers (like little fans) inside them to try and get rid of the extra heat.
Many halogen fixtures are already low voltage at 12 Volts, but for some reason the LED replacement bulbs for those are STILL as expensive, or almost as expensive, as the 120V (or 240V) LED bulbs. I have read in engineering articles that when you have to miniaturize anything, it gets more expensive.
So, quit trying to retrofit the 120VAC socket which is still prohibitively expensive at $40 each, and lets just put new LED fixtures in the place of the the actual bulb, and put the power supply elsewhere.
Then we can run our lighting from backup batteries without the tremendous losses that occur with taking 12 volts, bumping it up to 120VAC, then having whatever losses in the bulb itself.
Moving to LED lighting can be a very smart move for everyone.
Incandescent bulbs use lots of current and put out most of this energy as heat, not light.
(There are some recent developments to convert more of the incandescent bulb's energy into visible light, but as far as I know they are not in production yet.)
Fluorescent bulbs have to use mercury to do their job, but they are more efficient than incandescents and do provide the proper range of colors, from bright white to warm white. They also use 120 Volts AC to operate, and so are not friendly to low-voltage lighting from backup batteries.
Most LED bulb designs you see for purchase are centered on making LED's look like and fit in place of incandescent bulbs. They are based on the old "Edison socket" which has been the standard since light bulbs for the last 100 years. Another popular format is PAR lamp replacements, usually found in track lighting and accent lighting fixtures.
These LED replacement bulbs are plug-in replacements, but they are still expensive and because of the small form-factor, get really hot. This reduces the life of the entire unit.
While many users of this new technology are undoubtedly most comfortable with something that looked like what they were used to using, I believe that because of cost concerns and engineering reasons it may be time to take a whole new approach.
Low-voltage LED lightingLow-voltage LED lighting modules and fixtures are much more affordable because they don't need a rectifier, regulator, and current limiting in every bulb. So they also don't need such a big heat sink.
I will soon be offering assembled 12 Volt LED Lighting Modules:
The included step-up power supply module boosts the available voltage to the optimum value for the LED.
I will also offer other building blocks of this system as I find reliable sources.
Send any questions or express your interest with a message:
Car Batteries are 12.68 Volts fully charged, and while lead is toxic if released into the environment, the key here is to carefully control it. Lead-acid batteries are extremely rebuild-able, and are found all over the world. Such a mature and stable technology should not go to waste! And there is never a good reason to discard a lead-acid battery in the landfill. They are probably the most recyclable battery there is.
Mobile applications - Automotive, RV and BoatingWith these applications, you already have a low-voltage source available. So a good source of low voltage bulbs and fixtures are auto parts and RV stores. However, the prices at these places vary a lot, mostly on the high side. I suppose they figure if you can afford a motor home or trailer, you can afford some high-priced fixtures or bulbs. If you find a place where these are reasonably priced, drop me a line at firstname.lastname@example.org and I will post it.
I've made some LED Modules for my own lighting needs. They work pretty well, and are more efficient than the twisty fluorescent bulbs.
The LED Module is mounted on a heat sink with a small fan that also runs off of 12V. It has a small 2-pin connector.
The LED is the BridgeLux BXRA-N0802-00000 from the ES series of LED Modules.
Then I bought some cheap frosted glass fixtures from the depot store and used them to help spread the light. Otherwise it had too much glare and the shadows were too sharp.
(For more light and more money, I could have bought the BXRA-N1203-00000, which is 1530 Lumen at the same current!)
The fixture is mounted on a flat ceiling with no cutout of the ceiling needed. A single 18-guage dual-conductor wire (speaker wire, actually) runs across the ceiling and down the wall to the power supply.
Half of the room is lit by two of these LED fixtures, and the other half by a twin-tube fluorescent fixture with two 40 Watt bulbs. Both sides appear to be lit equally, but one side is using 25 Watts and the other 80 Watts.
Update:I bought some little step-up regulator modules that take whatever voltage you have and boost it to whatever you want (within reason). I have them set for 12.25 Volts coming out, at about 1 Amp. This lets me use some cheap 12 Volt surplus switching power supplies and still light the LED Modules to full brightness. The difference in light available was quite noticeable when I increase the voltage from 11.85 to 12.25 and they show no problems running without a heat sink.
These step-up modules would also (more importantly) let you get lots more light from whatever low-voltage DC power source you have, even if the battery voltage drops below nominal.
Although 12 Volts is MY choice because I want alternative power sources, there are some new modules available that run right off of the AC line with minimal outside components.
The Seoul Semiconductor Acrich 2 Series 12 Watt Module below runs straight off of 120VAC with only surge protection and EMI reduction needed, and that's 3 components. Of course you will need a heat sink and probably a fan for it.
But it is the ultimate in simplicity if you just want LED lighting.
Solar and Wind PowerYou might first want to see how much energy you will need. Consumer Reports has a cool calculator here. Cool!
You can't really skip the opportunity to get energy from wind and the sun.
Efficient and sturdy solar collector
www.dcpower-systems.com is a wholesaler of this stuff. Become a dealer or find one to use their products. But you can learn a lot just from their catalog... except for prices. But great knowledge for what to buy when you are ready. and how big a system you will need. They have solar and wind power, batteries, and inverters. Everything you need.
Wind Energy and Grid-Tie InvertersThese connect your energy source to your power line in the house.
Here is a link to a place that sells small wind generators. Wind Turbine System $899
Power Your Home With A Wind Turbine. Starting At $899
Background Data about this LED and Lighting stuff:
History of lighting, much condensed.The first light was from the Sun. Great light, kinda yellowish, but mostly white, and plenty of it when it was daytime.
But at sundown all activity stopped, and restarted at sunup. But the light color was yellow, for the most part. Then was FIRE! This wonderful discovery opened up all sorts of activities after sundown. Life did not stop at sundown! Candles were great... no more crowded around the fire all evening. Light color was pretty yellow.
Kerosene Lanterns were bright, portable, safer than candles, but kinda stinky. Yellowish light.
Electric AgeI think glowing-gas bulbs were the first. I'll check on that. Available in any color but white.
Arc lamps were intense, white, hot, dangerous. And they put out Ultraviolet light, which can blind you. Not for homes.
Acetylene Lamps were used by miners. White light but dangerous because it came from burning gas.
Cool, Warm, and in betweenFluorescent bulbs have been available in several "temperatures" for a long time now. You see them in the stores... Cool White, Warm White and so on. These represent literally different color temperatures as measured by instruments, and offer more blue-end light or more red-end light, as desired by the user.
The same offerings, plus more, are available in the LED world of lighting. What is funny, though, is that Cool White looks like fluorescent tubes, and Warm White looks like incandescent bulbs! Do they have any that look like kerosene lamps? When is the backward-compatibility going to stop?
You will want to see how much energy you will need. Consumer Reports has a cool calculator here. Cool!