Wednesday, May 9, 2012

Off-Grid Lighting Choices.

One of the main concerns where we're going is we're far enough away from grid power that it forces us to go "off-grid" which we don't see as a negative whatsoever. It does mean though that we have to look at conserving power wherever possible. One of those places of course is lighting. We have a number of choices ahead of us. In the trailer we'll be staying in while we build it already has 12v lighting but that doesn't mean it's as efficient as possible. 

26.9 watt 1156 bulb
The lights use 1156 bulbs that are basically tail lamps for cars. They are rated at 12.8 volts, 2.1 amps, and 26.9 watts each. With 11 light fixtures having 2 bulbs each that's 22 bulbs times 26.9 watts for a total of 591.8 watts for every hour that all the lights are on. 

Granted all 11 lights will never be on at the same time, and each fixture can turn on either one or two bulbs at a time. We try now when we're at my parents place to only use the lights we need when we really need them but we still find ourselves leaving them on at times in areas where we're not. It also doesn't help that Deb can't hardly reach them up on the ceiling to turn them off and on anyway. They are also a standard yellowish color rather than the natural white light you get from the sun. 

So what are our alternatives? LED lights or course. they make LED replacement lights that will plug right in to the socket and use are rated at just over half of the 1156 bulbs. Of course this means you still have a total of about 271 watts for all the bulbs. What else can we use? Well, I found an alternative while perusing the small cabin forums for a single surface mounted LED that was ready for 12 volts and the price point was right at $1.99 each.
The LD1-x series from are as you can see a very tiny led that is wired and ready to use in a 9v-15 v system and are amazingly bright for their size. They also have a 120 degree light angle so they do a pretty good job at spreading the light out. They are rated at 15mA each which at the same 12.8 volts used above puts them at .19 watts each. That is a savings of 26.7 watts per bulb! Now in fairness they are not close to being as bright as the non LED bulb so in our tests we've decided on using two lights in each side for a total of 4 per fixture. 

So what is our power draw using these led lights? 11 fixtures with 4 lights each equals 8.45 watts for each hour that all the lights are on. These lights could run 24 hours a day and would only use 203 watts of power or roughly one third of the power the original bulbs use in one hour! We figure a usage rate of about half the fixtures for maybe 6 hours a day so we need 25 watts of power for lighting. 

We also bought two of each light color, cool white, natural white, and warm white to test out and see which one we liked. A quick note on, we received them within a matter of days from across the country and they had packaged them in three separate anti-static bags, one for each type that we ordered. We were very pleased with the service and will be buying the rest of our led supplies from them as well. 

The cool white LED's seemed very bright but are a very harsh bluish light kind of like the blinding HID lamps you see on the new cars. I personally didn't like them although they were a better choice over the warm white leds that we tried next. They have more of a yellow colring to them like the original 1156 bulbs which is supposed to be better for reading but they just didn't light things up like we wanted. The natural white however was a perfect blend between the two. They seemed very much like normal daylight and we were able to read, use the laptop, and eat under them and it felt, well natural. 

So where does that leave us? We could power the lights in our trailer with a 10 watt solar panel and a battery a small as a 7.2Ah SLA battery and have two days in reserve keeping the battery above a 50% charge. Not bad for a $100.00 investment to replace all 22 bulbs. 

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