Tuesday, July 28, 2015

I Keep Putting Off...

      I have a couple of "aloft" projects, one on a huge, flat roof at work where the only drawbacks are A) heat, B) I'm going to need wall-socket juice for a heavy-duty heat-shrink gun and that will mean hauling a hundred-fifty foot (or more) extension cord more up a fifteen-foot ladder and C) heat.

     The other one is here at home, periodic replacement of the farm-type outdoor light that illuminates the back yard -- when it works.  It's all ladder-type work, twelve feet up, and I'll have to shut off breaker number one, which protects one of the four original circuits in the house and includes about three-quarters of the overhead lights.  No real excuse for this one, other than I don't want to do it when I'm tired or dizzy, or it's raining or beastly hot.

     Gonna have to, though, before too long.


Fuzzy Curmudgeon said...

I replaced my big mercury vapor driveway light with an LED fixture in 2012 and have never had to go back to it. You'd be amazed how much space a little 9-LED, allegedly 10W floodlight fixture (originally meant for accent lighting if I recall correctly) lights up. Well, maybe YOU wouldn't be amazed, but my wife certainly was :)

In the back, we still have an outdoor fluorescent wall fixture that keeps on burning year after year since I replaced it back in about '03 (it doesn't do so well in -20 winter weather, but then, who's going to be in my backyard in the dark when it's -20 out? Finnish ninjas?). Eventually I'll replace it with LEDs, but no sense fixin' what ain't broke.

Joe Allen said...

Don't know how big of cables you're putting heat shrink on, but I used to use one of these Weller kits for field work: http://www.amazon.com/Portasol-P-1K-Professional-Kit/dp/B006485HEQ

Good soldering gun, at least for up to 12GA wire, and has a heat blower tip that I've used on 2"+ heat shrink.

And, Fuzzy Curmudgeon? If that's your real picture, stop posting on blogs, hire someone to do your household handywork and finish 'Winds of Winter'! Chop, chop!

Roberta X said...

It's the glue-loaded stuff and it goes around some high-end RG-8 coax and an N connector -- overheating would be a very big problem.

In related news, Belden 9913 and LMR-400 take the same Times Microwave connector -- and strip tool!

Roberta X said...

My barnyard light is a big, cheap fluorescent replacement for the old mercury-vapor lights. This one will be #3 in six years. It's on the West wall and takes all the weather, plus none of them are happy when it gets much below zero.

jdunmyer said...

I'd like to know what brand/model of LED fixture would make a good replacement for our MV yard light. It's been in operation since 1966, with nary a hiccup, even with the photocell. (!) Biggest thing is that it's 175 watts, IIRC.

Roberta X said...

Jim, I don't know. I kind of like CFLs for this, despite my poor luck with them. They're noisy but don't run as hot as LEDs, or at least the early LEDs.

McMaster-Carr has a LED dusk-to-dawn pole light but it's over $200! The CFL fixtures are in the $30 to $50 range and the better ones would probably last longer than the discount-grade ones I have been buying. (Here's the McMaster page.)

I came close to trying to replace the ballast for the original mercury-vapor lamp, but Uncle Sam has made it about impossible to keep one running. So I had to replace the entire fixture.

markm said...

I did a design study a few years ago for LED street lighting, with one of the goals being a ten-year lifetime (as compared to 18-36 months for gas-discharge types like sodium vapor and flourescents). Many of the early LED lighting installations lacked proper heatsinks, but LED's _should_ run considerably cooler than CFL's. They run close to hot enough to burn fingers. That hot will seriously shorten the lifetime of LED's, or any other semiconductor. Heat also reduces their efficiency.

Note one story I've heard of where LED's didn't work out well - for stoplights in some northern cities. In some climates, the LED's don't produce enough heat to keep the lenses defrosted! I assume that eventually an electric heater and thermostat was added. But I would not recommend flourescents for that job at all, and incandescent bulbs will use more electricity than LED's plus the necessary heater, and burn out and need replaced much more frequently.

Is your yard light on a motion sensor, or setup to light at dusk and stay on until dawn? I'd recommend LED's in the first case, and flourescent (or sodium-vapor) in the second. In the higher-output installations, the best flourescent lighting (including a high-efficiency solid-state ballast) was just as efficient as the best LED fixtures 3 years ago; I expect LED's have improved since, but nowhere near enough for the electricity savings from running continuously to pay the price difference. There are three things that might make LED's clearly the best choice:

1. High cost of reaching the fixture to replace lamps - the LED lamp _might_ outlast three or more flourescent lamps, although it's very difficult to confirm this for a particular model. If it's a streetlight and to change the lamp the city has to deploy a bucket lift truck, barricades, cones, and warning signs, and several workers at union rates, saving one or two changes will pay for a good LED fixture. Your yard light is hardly that costly to change, but it's up to you to decide what each trip up the ladder is worth.

2. Frequent on-off cycles. This shortens the life of flourescent bulbs, but not of LED's. I'd guess that if that becomes an issue with a motion sensor yard light, you either need to adjust the sensor, or do something about the traffic across your yard. But see how this interacts with the next item:

3. Cold weather. Flourescents have trouble striking an arc when extremely cold, and once started their output is dim and efficiency is low until they manage to warm themselves up, but in my experience they will do this eventually. For several years in Gaylord, MI, I had a 6 watt CFL (that's the power of an incandescent night light and the light of a 40W incandescent) on my back porch to light my path from the car to the door, which I simply kept on all winter. If I had had to start this up at 3 am on a -25F night, I think the only way would have been to unscrew the bulb and bring it inside to warm up, but once it was running, this tiny twist of glass tubes would keep itself warm.

A yard light-sized CFL in Indianapolis (5 degrees of latitude south of Gaylord) will certainly be able to warm itself enough to run well if it's always on. If you waited to turn it on until 3 am on the coldest night of the year, it might fail to start, but at dusk it should always be capable of starting. However, on a motion sensor it might take minutes to start producing sufficient light in cold weather.

Roberta X said...

This is a farmyard light. Think small streetlight: on at dusk, off at dawn. I buy the fixtures sold for that purpose, complete with bulb. They're CFLs. As near as I can tell, the capacitors in the the little power-supply board fail.

jdunmyer said...

You guys have convinced me to leave well enough alone. The fixture is on a pole, high enough that it's hard to work on from an extension ladder. I could rent a man lift, but with the reported poor reliability of the alternatives, I am back to "if it ain't broke, don't fix it".

Thanks for sharing your experience, Markm.