subject: Rv Nightlights Take More Power Than You Figured [print this page] My wife and I recently upgraded our 5th wheel trailer to a larger, more expensive RV. One of the features in the new rig is those cute little footlights to help you see the steps and so on at night when it is dark. We have three such nightlights. They are small, about two inches off the floor, and produce a little more than 20 lumens of light each. I agreed with my Wife, and we began to leave two of them on all night. I put them on my LED change-out list but did not assign them a high importance. With the new rig, Wife had a bunch of new honey-dos to keep me occupied for several weeks or longer.
Finally the nightlights reached the top of my To-Do list. After looking the existing units over I decided a single three-LED-element chip would serve as a good replacement. It would provide 20 lumens of light -- about the same as what I had. I removed one of the existing nightlights and took it apart to see what they used. I found it to contain a bulb labeled 194, a miniature wedge (W2.1x9.5d base) rated to use 3.8 watts at 14 volts. I also noted that the wood around the casing had charred from the heat of the bulb. Maybe leaving them on all night was not such a good idea.
A quick calculation determined that using 2 nightlights for 12 hours would use 38 watt-hours. For the whole year that would total 14 kilowatt-hours. Since we currently pay $0.19 per kilowatt-hour here in southern California, that could total $2.65 for the year. Chump-change! But then I checked the lifetime of the 194; it is 1,500 hours. That would mean I should expect to use 6 bulbs during the year if I left them on every night. I found them on the Internet for $7 each, but if I had to replace the entire nightlight unit, it was more like $25 each. At that rate, I would be the chump.
I compared the costs for operating with LED chip replacements. Each LED chip draws only 0.02 amps, and two chips would only use 3 watt-hours in 12 hours, or 1.1 kilowatt-hours for the entire year. Really chump change! The difference in operating costs is 1,280%. And the LED is rated for a lifetime of 100,000 hours, or 22 years of service in my application. A 22 year supply of 194 bulbs would cost over $900. A couple of the LED chips cost less than $12. Comparative costs don't really compute.
It took a while to figure out the electrical wiring in the new rig and install the new LEDs, but that was a one-time effort. Now if Wife wants to leave the nightlights on all night and day, that's fine because the cost is minimal. I figure it will only cost me another 21 cents per year. Now that is really, really chump change!
