Bulb equivalent

[Ashgrove]

Looking to replace the T8 bulbs in my shop.
They are listed at 3050 lumens and are driven by 1.18 ballasts.
I have 30 4 bulb fixtures with specular reflectors in a 60x60x18 area.
Fixtures are ceiling mounted in a 5x6 pattern.

My hope is to have equal or better yet greater output than original to compensate for the fact that all
surfaces are not as reflective as they were when new.
I have played around with visual interior, but not coming up with the information needed.
Rewiring and changing out tombstones are possibilies, but I hope to keep the fixtures.

Any insight would be greatly appreciated.

 

[cybrdyke]

It's nearly impossible to get good results from Visual when using LED tubes. At least now you know it's not you.
Here's where you are... your lamps are emitting somewhere around 3600 lumens when new. Deterioration is probably 30% over 15,000 hours. Depending on the quality, condition and cleanliness of your reflectors, only about 85% of the emitted light ever reaches the target.
New LED tubes are available in lumen packages around 3300, but not from mainstream manufacturers. I dont use them because I dont trust companies that I've never heard of before. The LED tubes, as long as their beam angle is less than 180, have no need for your reflectors, so ALL of the light that they emit will reach the target.
A little math example for you.
3050 x 1.18=3599
3599 x .85 =3059
3059 x .70 =2141 This is your lamp deterioration if your lamps are old and your reflectorss are dirty.

You could likely use tubes that are in the 2500 range and still percieve them as being brighter than what you have now. Plus, these are much more common and made by mainstream manufacturers.
Good luck,
CD

 

[Ashgrove]

CD,

Thanks for your insight, reading your posts has helped me filter out a lot of bs.

Since my ballasts are still "humming along" would you recommend leaving them for their
buffering capability or bypass them?
If bypassing should I choose a Type B bulb or go with the 4000K version of the versa tube or something other?

 

[u2slow]

Always bypass for me... never having to buy another ballast is part of the LED appeal.