This is a continuation of this
T5 lighting. This has fascinated me since it became available a few years ago. Slowly, all my tanks are switched over to this most efficient way of reflecting light to where it needs to be.
There are still a few confusing things. Like what ballasts can be used, what exactly happens when bulbs get old and how could this affect ballasts, and why some bulbs croak after only a few months of usage.
Last night I played around with some linear fluorescent bulbs, a cheap ballast, and a "Kill A Watt" energy measuring device. And found some interesting things. Here is what I did: I connected different bulbs to an Advance REL-4P32-SC ballast. These are available at HD for about $18 and can drive up to four 4ft T8 bulbs (4x32=>128W).
First I powered the ballast and noted that it would eat about 5 Watts without any bulbs connected. I have no way of figuring out if it always uses 5 Watts or if it depends on the bulb configuration, but let's assume there is a 5 Watt loss.
I used the following bulbs: 20W T12, 32W T8, 28W NO-T5, and 54W HO-T5. EDIT:
I tested some 4' T12 bulbs, labeled with 34 and 40W.
Okay, some numbers. First I note which bulbs I connected and what the spec'd wattage would be. Next you'll see the actual wattage used by ballast + bulb(s).
No bulb --> 5W
20W --> 19W
34W --> 27W*
40W --> 35W*
32W --> 40W
28W --> 45W
54W --> 45W
Numbers are boring (*added afterwards), but there are some interesting things here:
1) The 20W (*and other) T12 are way underdriven, the single 32W T8 a little overdriven. Assumption: This ballast is for T8 bulbs, not T12 bulbs. When adding additional 32W T8's, it will drive them to spec.
2) A 28W T5 bulb is overdriven to 40W (if 5W for the ballast). This is quite a bit of OD there. It is very bright, and gets nice'n'warm as well.
3) A 54W T5 bulb is underdriven to 40W.
Assumption for 2) and 3): The ballast doesn't know to read the label on the bulbs, and both 4' T5 bulbs, HO or not, appear the same and get exactly the same current.
What does that mean? A) The ballast is made for T8, not T5, it doesn't sense the difference in NO and HO bulbs. Or, B) HO and NO T5's are exactly the same. The ballast determines how much current they receive.
When I get around to it, I will do a similar test with a different ballast, a Workhorse 7 which is made for T5 and PC bulbs, and see if it can distinguish between HO and NO T5 bulbs.
Also I will continue to play with the cheap ballast, and see what happens if I add more bulbs to it.
Here is the purpose of this whole write-up - if we get a decent life span out of a NO T5 when connected to the Advance ballast, there is an easy way to set up cheap and powerful lighting. You can get NO T5 bulbs for $9 + shp which gives us a nice Lumen/$ ratio, if such a thing exists.