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Replacing T-8's

13mo

Well-known member
Joined
Mar 10, 2020
Messages
78
Location
Missouri
My experience in using linear LEDs vs. traditional T8 fluorescent bulbs gave me a few insights that may be helpful for you:

1. A typical decent new 2800-3000 lumen 32 watt T8 4' fluorescent on a ballast with an average 0.88 ballast factor in a fixture with a reflector will put about as much light down to the workplane as a linear LED with a little over 2000 lumens.

2. A typical decent new 2800-3000 lumen 32 watt T8 4' fluorescent on a ballast with an average 0.88 ballast factor in a fixture without a reflector (such as a strip light) will put about as much light down to the workplane as a linear LED with a little under 2000 lumens.

3. Note that the less expensive linear LED bulbs are generally 1500-1600 lumens and will be noticeably dimmer than a regular fluorescent bulb. The better ones with 2000-2200 lumens will be as bright as the original fluorescent in a typical reflectorized fixture and somewhat brighter in a strip fixture.

4. The brightness and also power draw of Type A ballast-required linear LEDs depends on the ballast factor, at least with GE's bulbs (the only manufacturer I could see that actually published this data.) With an average 0.88 ballast factor ballast, their "15 watt" Type A bulbs produce a little over 2000 lumens and this directly scales with ballast output (e.g. a 1.2 ballast factor ballast can drive these to 2600-2900 lm!) Direct wire Type B bulbs will give you about the output it says on the label.

5. The light distribution of a linear LED in a strip fixture is similar to that of a fluorescent fixture with a reflector, which is to say there isn't much uplight. This can be a pro or a con depending on what you are after.

6. Ballast bypass (type B) bulbs are considerably more expensive than "plug and play (type A) bulbs, typically about $7.50-10 per bulb vs. $4-6 if you buy from an established brand (GE, Sylvania, etc.) and buy locally.

7. For new projects, generally the least expensive option up front is to use regular fluorescents, as a ballast bypass fixture and Type B ballast bypass bulbs are more expensive than a regular fixture and regular bulbs. It is about a wash between going regular ballasted fixtures and Type A LEDs vs. ballast bypass fixtures and Type B LEDs but you will absolve yourself of ballast compatibility issues in going the latter route.

8. I have had to replace one of the 46 original T8 fluorescent bulbs in my shop in the last five years. The rest are still working well but are about 5-10% dimmer than a new one. I am using typical instant start ballasts in the fixtures that still run fluorescents.
 
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Burl

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Joined
Sep 21, 2007
Messages
791
Location
Where Mountaineers are free
For someone who has 12' ceilings and ballasts going south on my existing T8s, the ballast bypass bulbs seem to be the fix. But usually around $10 for each bulb is the going rate and about the same amount of light to the floor (5k sunlight and 2k lumens)seems like the only fix for the dead ballast fixtures. 13's post seems to break it down good.
 
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pepi

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Joined
Mar 27, 2013
Messages
2,883
Location
Woodstock, GA
I just bought eighteen of these LEDs for my two garages. Excellent especially in the "cold". Very bright for under $12. each

https://www.amazon.com/gp/product/B07LGTJQ2S/?tag=atomicindus08-20

One big problem with those half the light is on the ceiling. So whatever the cut and past lumens you tout dived that in half.

Tube replacement and the removal of the ballast best practice.

If someone keeps the ballast, stepping on his ****. Cause the fixture still has 2 points of failure. Ballast (DUH) and tube.

See if this puts what was written into proper prospective
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13mo

Well-known member
Joined
Mar 10, 2020
Messages
78
Location
Missouri
One big problem with those half the light is on the ceiling. So whatever the cut and past lumens you tout dived that in half.

Tube replacement and the removal of the ballast best practice.

If someone keeps the ballast, stepping on his ****. Cause the fixture still has 2 points of failure. Ballast (DUH) and tube.

See if this puts what was written into proper prospective
attachment.php

LED tubes do not have a 360 degree beam spread like fluorescents do. The spread varies, typically from 120 degrees to 200 degrees, as the substrate the LEDs are mounted to at the top of the tube prevents light from emanating from the portion of the tube that sits above it. Thus a larger fraction of the light from a bare linear LED tube hits the ground compared to a linear fluorescent. This is why I have found an about 2000 lumen linear LED tube puts about as much light on the floor as a 3000 lumen linear fluorescent.

The light output as well as anything else with noname Chinese lamps and fixtures from Amazon and others is highly suspect, but it's not because of the beam spread.

The topic of ballast bypass (UL Type B) vs. ballast-required (UL Type A) LED tubes have been debated elsewhere. The conclusion is not as simple as "ballasts are bad." Electronic fluorescent ballasts are relatively similar to LED drivers as far as the electronics involved and their ability to regulate voltages does help Type A LEDs be more resistant to power surges and noise compared to Type B tubes. A good electronic ballast will also outlast the LED drivers in a Type B tube as they are larger and more robust.

What generally is true is that it makes less sense to go buy a new ballast to replace a failed one than it does to convert to Type B LEDs at that point in time, and that ballast compatibility with Type A tubes can be frustrating. Very few Type A tubes work with any T12 magnetic ballast, and some electronic ballasts do not work well with certain Type A tubes. But if you have a working, compatible electronic ballast, Type A tubes are noticeably less expensive than Type B tubes and I would use them vs. Type B tubes in that situation.
 
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