Has there ever been an LA that lasts forever?

[FalconFX]

I know, I know... Nothing lasts forever.

But on the way back home from vacation and fiddling around with my flashlights, it came across and hit me like a railgun:

Has there ever been a lamp assembly or bulb in a flashlight, powered by conventional consumer batteries (AA, C, etc...) and sold as a consumer product, that would last for, say 1000 years of continuous use (since nothing lasts forever)?

If not, what is the longest lasting/running bulb or LA? 100,000 hours is great and all (11.4 years ain't shabby), but what about something like 50+ years?

PS: I know, I know... Nuclear stuff can last a while, but I'd like to be fertile enough to envision my great great grandkids using a flashlight that still has its bulb workin' after 200 years of use...

 

[B@rt]

Here is one that has been running over 100 years...

It's not a battery powered light though...

Here are some url's to the story:
Centennialbulb
Firehouse

 

[FalconFX]

that must be some wickedly strong carbon... goodness. burning since 1901. and a filament at that. 4 watts is probably why the guy's lasting so long... ahh, they don't make things like they used to anymore.

it's in livermore, cali, so i might go visit it this month or something... 60 mile drive away and all.

 

[DavidW]

Because you're using batteries with verying voltages I don't think it's possible. The longest rated bulb I've ever come across is the Eveready 407. It's rated for 50 hours. Most bulbs are rated for 5 hours.

 

[FalconFX]

You're right. Constant current, or constant on, might be the key to why some of these bulbs are lasting so long. Expansion and contraction due to heating and cooling of the filament can kill it. So it'd make sense that a filament at constant current and constant temperature should theoretically last longer than it's specification.

I'd probably venture to guess that in a vacuum where current and everything else are absolutely kept to no flux, a carbon filament should run for thousands of years.

 

[B@rt]

Not proven scientifically, but looking promising...

Originally posted by TigerLight Pro:
Lamp life:
This is not scientific, but it does give a good bench mark. This is from memory, but here goes. With the prototypes that we tested in the field we had an average life of over 260 hrs this included failure do to impact. We had some lamps last way in excess of that. I noted some burning on the inside of the lamp's glass (brown tint) at around 230 hours. This does reduce performance.

I have a lamp module in my personal TL. IT has been there since august 2000. I have thrown it at cars, it has hit the ground running more than a dozen times and I work 10 pm to 0800 am exclusively. I also have the same battery pack and I charged continuously, on occasion I would take it of the charger if I was on vacation. I have changed one impact damper, and several lenses. I have no scientific proof to support this , but I believe the better the lens is functioning the less heat build up, thus increased lamp life, and performance.

<font size="2" face="Verdana, Arial">(from this thread: Tigerlight Lamp Life )