# Ballast life span



## gbhil (Oct 28, 2005)

I worked for years as an EE in the luminary field, with a fair amount of those years in R&D. Like all things electronic, parts will slowly degrade from heat and vibration. The effects of this _should_ be little to none, until the parts degrade to the point they are outside of their specs. On a properly designed electronic circuit ballast (read as expensive...dental lamps, inspection lamps, machine vision, etc.), that is the point where they should stop working. On cheaper ballasts like the ones we're interested in, the circuitry may still work, providing more or less lamp output, flickering, heat issues, etc.

Note that most of the 'stress' put on a ballast is at cold startup. Using one on/off cycle per 24 hours I'd expect an electronic ballast that's used in a correct way (very important point...proper fixture design and correct input voltage play an enormous role) to last 7-10 years at a minimum. Cramming them into small, hot, aquarium light hoods will of course shorten their life. 

IMO Helios may not be too far off the mark saying the ballasts in those particular fixtures are designed to last only as long as the life of the lamp, simply because of the fixture design.


----------



## Wasserpest (Jun 12, 2003)

Thanks gb, that makes sense, I guess YMMV with these things, I have a helios ballast running for a long time already, and the 38W T5 (weird wattage, I know) is a lot brighter than the two 40W T12's that were in its place before. Has been working first as a tank light and now as a as-needed corridor lighting.

Anyway, since you are the expert, another question: Do you know... Is it true that T5's start to suck a lot of power towards the end of their lifes, and therefore need a special T5 ballast that has that end-of-life circuitry, or is that a sales trap?

In other words, can I run T5 bulbs on a cheap electronic ballast like the Advance SC32 or will that blow up in my face one day when they reach that age?


----------



## gbhil (Oct 28, 2005)

It's a little bit of both IMO. As the gas and ignition system inside a fluorescent lamp degrades over time, it becomes harder to light the lamp. The ballast will only output so much energy, so more energy is lost as heat instead of light. This effect is not linear, so higher wattage lamps suffer more from this effect than lower wattage lamps. Special T5 ballasts from Triad (I'm sure other manufacturers make this claim also, but I'm only familiar with GE's Triad brand) have shown that they will drive HO lamps more consistantly over a longer period of time than ballasts not specifically designed for HO T5 lamps. I've not seen the effects in real life, only on paper so I'm unable to comment on what this means to us other than to give my educated guess that it means very little. :hihi: In a nutshell - you might get an extra bit of life from your lamps by using specifically designed ballasts, but not enough to make the cost worthwhile in our applications IMO.

Personally, I use Fulham ballasts to run any fluorescent lamps that I'm not overdriving. T5 HO included.


----------



## Wasserpest (Jun 12, 2003)

Thanks for the info! I ordered some T5NO bulbs and will play around with them, like "What happens if you put them on a WH7 which normally drives T5HO bulbs?" and also see how many watts one of the cheapo electronic ballasts (4x 32W) will push through them.

That would be the ultimate cheap and efficient system: four ($9) 28W T5's driven by a ($18) ballast. Not as much light as HO bulbs, but still a very good Watt/Dollar ratio. :smile:


----------



## gbhil (Oct 28, 2005)

That will be an interesting series of tests, and will provide some great info for those that like to DIY their own lights. A couple of tests to be sure to run - 

Difference in lumen output when only driving one lamp on a four pole ballast compared to driving all four lamps. Even if you don't have a meter you could devise a test using a digital camera I'd think.

Difference in lumen output between driving the lamps normally and trying to overdrive them 2x with the Advance ballast. NO T5 lamps are supposedly 'un-overdrivable', yet I've never heard of anyone trying it and providing results either way.

Saftey first BTW. Fulham ballasts are 'smarter' than run-of-the-mill Advance or Sylvanias, etc., and my gut tells me that the WH7 is going to light those NO lamps and drive them at the correct wattage, but I'm not 100% sure of this. Pushing 54 watts through a slim lamp designed for only 28 watts is a distinct possibility. If that's the case, you can bet I'll be setting up a WH7 with NO T5 lamps on my test bench and seeing how long they'll run :hihi:

If you're successful, you've just built $120.00 worth of Coralife dual-strip T5 fixtures for ~$50.00. Good luck with this, and keep us posted on the result(s)!


----------



## Wasserpest (Jun 12, 2003)

I have a Kill-a-Watt meter which allows me to measure the energy that is being used. That's how I noticed a decrease of wattage per bulb as you add more bulbs to a 4x Advance ballast. Along with that a noticeable reduction in brightness.

I will update this as soon as I have the bulbs and some results.


----------



## MrBlackThumb (Aug 12, 2005)

2 of my Satellite Current USA (96 W) CF ballasts croaked after a little over a year of use (on for 8 hours a day). Tried to open to fix it, but the ballasts were potted with epoxy/resin, so had to order new ballasts. Dang, the ballast is half the price of the light itself.


----------

