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oil pan 4 12-24-17 09:47 AM

LED versus T5 efficiency
I went to look up LED versus T5 efficiency. It turns out LED beats up older technology like T12 and T8 and takes its lunch money. That's comparing 120v powered LED to T8, not ballast powered T8 LED replacements (these things add together the inefficiency of a ballast plus the inefficiency of LED power supply running off ludicrous high voltage). Turns out stepping up 120v AC power to a few hundred volts to power a tube, then stepping it back down to low voltage DC to power an LED isn't that efficient.
That shouldn't really surprise anyone.

After reading around I found that LEDs don't really offer any efficiency gain over T5. For overall system efficiency LED comes in anywhere from 70 to 100 lumens per watt.
T5 is consistantly 96 to 111 lumens per watt depending on the tube length and ballast.
A big part of the problem is all the junk coming over from china. The LEDs have cheap inefficient power supplies and their lumen output number is what ever they decide to stamp on the box to move product. LED light fixtures should easily exceed T5 efficiency by a lot but no one wants to pay for the newest generation of super efficient white LEDs and high efficiency power supplies, so only cheap junk gets manufactured.

I became interested in the subject when I got ahold of a bunch of free industrial grade, wash down rated high output T5 fixtures. I just assumed that LED light fixtures were super high efficiency and that even the new generation of T5 were outdated and inefficient. Boy was I surprised to find recent data saying in a lot cases LED can be less efficient than T5.

Also any advance in tech that improves efficiency of a power supply for a LED, would also in theory be able improve efficiency of a florescent ballast too. So that playing field is pretty much even, any improvements would be on the LED tech it's self.

gasstingy 12-28-17 03:10 PM

I converted my 4' kitchen fixture from T8's to LED's, with LED's I bought from a commercial lighting supplier. I removed the ballast, rewired the bulb holders on one end and simply removed the wiring on the other end. All was good. The energy consumption shown on the packaging says 18w per bulb. I also noticed the light output was better than the T8's I replaced. {I am not electrically inclined, but with a couple of YouTube videos under my belt, I was okay to convert the fixture.}

Then, I bought some LED's from Lowes to do my garage lights and found out when I got home that they required a functioning T8 ballast! I took them back. I checked Home Depot, Costco & Walmart and they were all the same way, needing a T8 ballast. It cost roughly double to buy the lights that didn't require a ballast than the Big Box store T8 ballasted LED's, but I figured it keeps me from wasting the ballast energy and from being mad when I'd need to replace a florescent light ballast to make my LED's work.

oil pan 4 12-28-17 04:25 PM

There are utilitec single pack T8 led replacements that are dual power capable for under $4 each.
Has to be the single pack, the utilitec dual pack are ballast only.
They can run off ballast power or straight off mains power.
I'm going to get a few tonight hopefully.

gasstingy 01-02-18 08:25 AM

OP4, Did you get those lights?, and are you going to try and hook any up with the ballast removed?

I'm very interested in the outcome. I'd not even considered it possible to have an LED capable as an "either/or" powered replacement.

oil pan 4 01-02-18 05:18 PM

Yes I bought 10 of them.
These are hybrid tubes. Hybrid tubes can run off ballast or 120 to 277v power.
I found that the led T8 tubes use 26% more power when running on ballast power, compared to a mains power.
But even on ballast power the led uses 1/3 less power than regular T8 tubes.
But T8 tube versus led on mains power the leds use less than half the power of tubes.
My 6 tube fixture originally used 2.1 amps, with leds on mains power it dropped to 0.84 amps.

gasstingy 01-03-18 08:12 AM

That is seriously good news to me. I didn't think of a way to test the efficiency, so I just hoped they were {at least close to} as good as they claim on the packaging.

I've replaced 16 T8 to unballasted LED's so far {house & attached garage} and have 12 more to change {never-ending barn project}.

oil pan 4 01-03-18 12:59 PM

It seems like the only florescent fixtures worth having are good quality high output tubes.

The high output T5 lights are industry standard, most HO T8 and HO T12 are not bad. The HO T8 tubes in my shed sucked, probably because they were warn out and/or possibly the incorrect tubes for the ballast. I have some HO T12 fixtures in my Porta store building on a count down switch (it's paid off or else I wouldn't be modifying it) and I do not plan on changing them because they are occasional use only.

I was going to put a HO T5 fixture in there but 210 watts of T5 was way too bright. 80 watts of HO T12 is just right.

dory69 01-10-18 02:42 AM

A big part of the problem is all the junk coming over from china.

gasstingy 01-10-18 09:19 AM


Originally Posted by dory69 (Post 58228)
A big part of the problem is all the junk coming over from china.

And an extreme lack of products available to buy that is not Chinese made in particular, or some other foreign country. :(

oil pan 4 01-10-18 09:05 PM

I have had to replace the ballast in some of my T5 high output fixtures, when I do I replace the single 4 lamp ballast with 2 separate 2 lamp ballast units, that way I can turn on 2 or 4 lamps.

So far out of 7 fixtures I have had to replace 14 tubes and 2 ballasts.

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