BigBlock

I have several electronic 4 bulb T8 32w ballasts and bulbs that I would like to use for vegging. I have been reading a little about overdriving the tubes, that is, using a 4 tube ballast for 2 tubes.

Question:
If I do that, do I double the lumens of the tube? (typical 2850 each) Also, how much does that shorten the life of the bulbs? Mine are rated at 36,000 hours life under normal use, which is quite some time....

Radiate

From what i've read the power of each tube increases by 1.7, so instead of 2850 lumens out of each you'll get 4845. This process also doubles the amount of power used by the system as well, so 4 32w overdriven bulbs will consume 256w total. Overdriving also voids any and all warranties on your equipment, as well as any safety ratings so I hope you're sharp on your electrical wiring. There will also be a noticeable temperature increase. I'm not sure how fast it'll burn up the bulbs, but the reason a tube lasts so long is because it's running much cooler than it can handle. I wouldn't be surprised if this cuts the life in half, maybe even more.


In short it sounds like a bad idea, but if you're absolutely set on it here's an article on how to do it.

Overdriven Normal Output (ODNO) - The Planted Tank

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BigBlock

Well, even then it would still be 18,000 hours. That's more than 2 years!

I could just use four tubes at the normal 32w, but the idea is more lumens from a single point kind of like HID or T5 lamps. I already have like 20 tubes, and I plan on ordering 2 more cases of 6500k...

Heat isn't much of an issue for me, besides killing bulbs, my grow is legal and I've got a ton of space for it.

Since I've got a bunch of ballasts and bulbs I might as well hook up two and see how they do...

BigBlock

Well, I finally hooked it up and tried it. I put an overdriven tube right next to a regular driven tube, and the overdriven tube was significantly brighter. I measured both tubes with a digital thermometer and (in the center) the standard wattage tube was 97F and the overdriven tube was only 107F. I don't think that should have a significant impact on life expectancy....