How long should Metal Halide ballasts last?

[buzzbar]

I saw hambone1216's post on metal halide lamps, and it made me think of the ballasts for these lights.

I installed (6) 400W metal halide high bay lights back in 2005 (about 3 1/2 years ago). Four (4) of the lights stopped working. We tried new lamps, but they still didn't work. So, we replaced the ballasts. This fixed the lights, but it's awfully expensive.

I have two questions. One, how long should a typical metal halide ballast last? And two, do you guys typically get a ballast rebuild kit? Or do you troubleshoot the light, and replace just the capacitor or other components in the light fixture? I've always just replaced everything, but that's usually after the lights been in service for a MUCH longer time than 3 1/2 years!

Thanks!

Andrew

 

[barbeer]

3 1/2 years life seems kinda short!

 

[tom baker]

Three years is about right, maybe a bit long for HID lamps. If you look in the lamp catalogs, for example it will list 15,000 hours. This is the average life, and at that life you will have 50% failure, of course depending on the burn time. Dusk to dawn is 4,000 hours per year.
So typically we will relamp every two years. Pulse start HIDs will last longer.

 

[raider1]

I agree that 3 years for an HID lamp is about right, but the ballast should last longer than that.

Chris

 

[Profish00]

90% of the time it's the capicitor not the ballist

 

[buzzbar]

I was referring to the ballast, not the lamp. A ballast SHOULD last longer than 3 1/2 years, but how long SHOULD they last? 5 years? 10 years?

If the capacitor is bad, what's the best way to test them?

Thanks for the quick reply guys!

 

[barbeer]

If the capacitor is bad, what's the best way to test them?

I really should not answer the way that first came to mind!:roll:

 

[A/A Fuel GTX]

I always replace the whole ballast assemby, ie ignitor, capacitor, ballast out of habit. It was the way I was taught and never questioned it. In reality, I suppose if the cap was bad, one could just replace it but then is the ignitor going to fail next week?

 

[Profish00]

Place annalog meter across the terminals the needle should spike and rest back to zero

If the capacitor is bad, what's the best way to test them?

QUOTE]

 

[Cow]

I suppose if the cap was bad, one could just replace it but then is the ignitor going to fail next week?

Yep, when the customer calls you back 2 weeks later, that is all they're going to remember, is you didn't fix it right the first time. Not worth the hassle. Replace the ballast and lamp and know it'll be a long time before you'll have to work on it again.

 

[Profish00]

I replace everything as well but in his post I quote:grin:

This fixed the lights, but it's awfully expensive.

so I made it less expensive for him,

 

[buzzbar]

I agree completely. That's what I have always done. But the previous ballast only lasted 3 1/2 years, and it's really expensive to replace the whole ballast assembly. We did this though. These lights were about 40' up, which required renting a lift, which is also expensive. My customer is wondering why these lights aren't lasting longer.

Are ballasts just cheaper than they used to be? Or did I get a bad batch?

Thanks!

 

[yanici]

I always replace the whole ballast assemby, ie ignitor, capacitor, ballast out of habit. It was the way I was taught and never questioned it. In reality, I suppose if the cap was bad, one could just replace it but then is the ignitor going to fail next week?

While working as an "in house" electrician, we would check to see if the ballast was putting out first by checking for power at the bulb's socket. If that was ok then generally it was just the ignitor that had gone bad. The ignitors go bad when the bulbs that are failing to start are left in too long. The ignitor will keep trying to start the failed bulb until itself goes bad. How many times have you seen those lights that start and go out and then repeat the action? That's usually a bad bulb and an ignitor working itself to death.

This method worked for us because we were on the property. It may not be the best for you guys. It certainly saved a lot of $$$ on ballast cost.

 

[Profish00]

About the time of Free Trade agreement:grin:

kpasso

I agree completely. That's what I have always done. But the previous ballast only lasted 3 1/2 years, and it's really expensive to replace the whole ballast assembly. We did this though. These lights were about 40' up, which required renting a lift, which is also expensive. My customer is wondering why these lights aren't lasting longer.

Are ballasts just cheaper than they used to be? Or did I get a bad batch?

Thanks!

 

[buzzbar]

Like many forum boards, lots of good information, but also a lot of smart alack remarks.
I love a smart alack remark as much as the next guy, but I REALLY would like to hear someone's opinion on how long a metal halide ballast should last. Am I the only one that's come across this?

Thanks guys.

 

[mivey]

The life depends on the fixture quality but have seen electronics with 12 year or more life expectancy and magnetics with 50 year life expectancy.

Heat is a killer.

 

[mivey]

IESNA says the average magnetic ballast life is 12 years at a 50% duty cycle:

The life of ballasts made with 105?C (Class A) insulation is approximately 45,000 h (continuous operation not exceeding 105?C). Ballast coil temperatures do not exceed the 105?C rating in properly designed ballasts when luminaires maintain a maximum ballast case temperature of 90?C. Other factors affecting ballast life are input voltage, luminaire heat dissipation characteristics, luminaire mounting, and the environment. Field data indicate a 12-yr median ballast life for a duty cycle of 16 h per day, 6 days per week, or 5000 h per year. This life rating assumes that because of ballast warmup time, the ballast operates only at peak temperatures for 12 h out of the 16-h duty cycle, or 3750 h per year.

Life is reduced by higher duty cycles, heat, voltage, mounting, and environment.

 

[weressl]

Like many forum boards, lots of good information, but also a lot of smart alack remarks.
I love a smart alack remark as much as the next guy, but I REALLY would like to hear someone's opinion on how long a metal halide ballast should last. Am I the only one that's come across this?

Thanks guys.

A lot depends on the ballast type and the ambient temperature.

A ballast - in general - should lasts about 50,000 burning hours if applied in an approved fixture and used at listed ambient. Temperature is the real killer. Of course the fixture configuration affects how much heat is removed and what actual temperature the ballast will experience, so the manufacturer of the ballast can not state it with certainty.

Indoor AC environment vs. outdoor of the same ballast will show that the indoor application will last longer.

There is no manufacturing standard, but you will often find that some ballast with better specification will come with 5 year guaranty.

 

[buzzbar]

Thanks for the reply. I figured that a ballast SHOULD last at least 5 years, but probably closer to 10 years under 'normal' circumstances.

These lights are inside, about 40' up, in a boat repair shop. I don't think that heat is an issue, but it's possible that it is. Perhaps in the summer time it gets pretty hot up there.

Thanks again.

 

[weressl]

Thanks for the reply. I figured that a ballast SHOULD last at least 5 years, but probably closer to 10 years under 'normal' circumstances.

These lights are inside, about 40' up, in a boat repair shop. I don't think that heat is an issue, but it's possible that it is. Perhaps in the summer time it gets pretty hot up there.

Thanks again.

Yes it would get hot.