Over-driving fluorescent lights

[amideutch]

dacrch, interesting stuff. I know they had a pretty long thread on the subject at GW and I gave it a try last year. Unfortunately not all electronic ballasts are created equal. I was using Phillipps HF-P 236 TLD 220-240 units and the tubes wouldn't light up when configured for OD. But with 3ea duro-lite VITA-LITE power twist 40watt bulbs and 2 36watt cool whites the seedlings seemed to be happy. May modify the hood after I get done building your bumble bee vibator. I have a 1000 watt metal halide setup but no place to set it up in the new house. Maybe one day. Ami

[matereater]

DCARCH, thanks!

[Fusion_power]

A few caveats should be inserted here.

1. An overdriven fixture does 3 things: uses more electricity for light output, burns the bulb phosphors rapidly, can cause unacceptable electronic 'noise' with some ballasts.

2. The same effect can be achieved in many cases by using more fixtures with more bulbs in a given space.

3. Reflectors can dramatically increase light intensity to plants even with normal fixtures

4. Even overdriven fixtures do not produce enough light for some plant situations. This is why metal halide systems are available.

5. The greatest benefit from an overdriven fixture is when high output bulbs are used. These bulbs are NOT cheap. I typically pay $5 per bulb for good quality high lumen bulbs. You can use cheaper bulbs, but the efficiency loss is very high and bulb failure will be rapid.




Since tomatoes are near and dear to my heart I will include a few details of results using both overdriven and standard fluorescent fixtures.

I have been using shoplight fluorescents to grow tomato plants indoors for about 20 years now. The ultimate in cheap is the typical fixture sold in walmart and other box stores. It has a mini magnetic ballast mounted in each end of the fixture. These fixtures typically cost about $9 and last an average of 2 growing seasons. They are a LOUSY investment and they can NOT be overdriven.

I investigated light fixtures thoroughly about 3 years ago and the cheapest electronic ballast fixture available was from Home Depot. I ordered 24 fixtures at $7 each and assembled them on wooden boards with 3 fixtures per level in my plant starting stand. I did not overdrive these lights, I just used more fixtures to increase the light intensity over my seedlings. The results using these fixtures have been very acceptable. Seedlings grow rapidly and are sturdy and healthy. I do not grow large plants with this setup. When the seedlings are potted up to individual cells, they go to the greenhouse for direct sunlight.

DarJones

[dcarch]

Originally Posted by amideutch

--- I have a 1000 watt metal halide setup but no place to set it up in the new house. Maybe one day. Ami

A 1000w MH lamp can be very big. It takes a lot of room.

I may be posting how you can build a MH fixture/reflector with remote ballast which is smaller.

With a 1,000w MH lamp, you can have tomatoes year round.

dcarch

[dcarch]

Originally Posted by Fusion_power

A few caveats should be inserted here.
1. An overdriven fixture does 3 things: uses more electricity for light output, burns the bulb phosphors rapidly, can cause unacceptable electronic 'noise' with some ballasts.
2. The same effect can be achieved in many cases by using more fixtures with more bulbs in a given space.
3. Reflectors can dramatically increase light intensity to plants even with normal fixtures
4. Even overdriven fixtures do not produce enough light for some plant situations. This is why metal halide systems are available.
--------------------------------
DarJones

I am in agreement with everything said with additional comments:
1. As I said, it will be less efficient and bulb life will be shorter; however, not by much.
2. OD lamps is only for those who don't want or don't have the room for more fixtures.
3. Most lamps already have reflectors. I do use aluminum self-adhesive roofing tape (HD) on the white reflectors to increase reflectivity.
4. That's why I use OD fixtures to get seedlings to about 8", and switch to MH to get then to about 18" tall.

dcarch

[Mischka]

It's that time of year again when a lot of us have seedlings under lights.

Bumping for the newer folks here.