LED emergency lights

We lost power for a couple of hours the other day.  Every time that happens, various projects bubble up several notches on the priority list.  This time I remembered that the muffler mount is broken on the generator and needs to be fixed.  I should also put an outlet in below the transfer switch so I can run the main UPS when we’re on generator power.  And dreams were rekindled of one of those exceptionally quiet inverter-type Honda EU3000ISA generators to replace the very annoyingly loud one I have.

Another idea that was renewed was some automatic LED emergency lighting.  The intent is sets of LEDs permanently wired in at several strategic places around the house run from central 12V batteries.  Of course we have flashlights (including a nice automatic LED one that charges wirelessly when sitting in its base and comes on when power is out).  But having a little light around the house would be nice.

Three white “superbright” LEDs at 20mA shining at the ceiling produce enough light to change a completely dark room to a marginally navigable one.  Six is noticeably better.  Since white LEDs run at 3.5-4V, three LEDs in series is pretty optimal for 12V.  At 20mA, I can run several sets from a 12V gel battery of 2-5 A-hr for many hours.

Looking at my stock, I seem to have enough for maybe 8 sets of 3 LEDs.  That’s a good start, but I could use a few more.  I found 100 white super-bright LEDS for $3.99 with free shipping on Ebay, and ordered them.  Of course they’re from China, but the gears are now turning, and they’ll magically show up at my doorstep in a couple of weeks.  Then I’ll have no excuse for not moving forward with the project.

The battery would just sit in the basement with a $2.99 12V float charger from Harbor Freight and some simple circuit to power the lines to the LEDs when power failed.

More to follow when the pleasant automatic reminder of a package on my doorstep arrives.

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One Response to LED emergency lights

  1. prof_braino says:

    Just fond this post thru workshop88.

    Great minds think alike….

    After Xmas, I found strings of 30, 60, and 100 LED in various colors for $1 each, which I harvested, and binned according to current draw… I wonder if this helps?

    As the halogen lights burn out, I’m replacing them with LED lights.

    I’m thinking of using last season’s solar yard lights to recharge the batteries. I figure the charge only has to last a several hours, that will give enough time to find the flashlights, and not be wasted if nobody is home.

    Cool project, hope to see more progress before the lights go out again!

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