Planted Tank VIP
Join Date: Jul 2002
Location: Winston-Salem, NC
Last night, I measured current draw for various ODNO configurations. I'm not sure they make sense, though. I measured current at the outlet with a Fluke 77 Series II Multimeter, so current readings would be avg and not RMS.
(A) With one F40T12 bulb hooked up to all four outputs of a 4-F32T8 ballast, I read 1.50 amps of current draw!
(B) With just two outputs of the same ballast connected to one bulb, I read 0.55A.
(C) With two F40T12 bulbs, each with two outputs connected, current was 0.72A.
Translating this to RMS (70.7%/63%) and taking into account the ballast factor (88%), I get 178 Watts being delivered to the first configuration (A), 65 watts for config (B) and 85 watts for config (C).
If these bulbs are efficient enough to provide 50 lumens per watt in standard configuration at 40 watts, then the one 4x OD F40T12 bulb was producing almost 9000 lumens! Assuming efficiency was much reduced, I'd estimate it to be closer to 5500-6500 lumens, since the light output seemed to be just slightly brighter than a 65w PC bulb I have. Is this possible? I only ran it for a minute or so and the bulb didn't get too warm to touch.
I don't understand why the output would increase so dramatically from 2x to 4x. One thing I am thinking is - for all these tests, I had only one yellow (common) wire connected to each bulb. I might retest tonight and see what happens when I connect both common wires to the single bulb combinations. I assumed they were truly common and it wouldn't matter, but perhaps I am mistaken.
- Sam P -
plantedtanker in limbo - all tanks currently in storage