Lumen Boosting for tungsten lamps

[java_man]

I put together this little chart out of curiosity and I thought I would share it.

I found some equations for tungsten lamps, includes halogens, for the effects of altering voltage on the performance of the lamp.

I inserted a typical 100 watt, 12 volt lamp and looked at various boost factors up to 19.2 volts

Some intresting things were evident, besides and enormous increase in lumen output, the efficiency is greatly improved also. Of course, the price to pay is lamp life.

Based on experiments I have done, the equations look pretty good, but the lamp life, especially at high voltages, is probably an estimate at best for there are many factors such as the tungsten alloy, gas makeup, filament construction etc that effect life.

If one wanted a low cost superlight for a shootout...and lifespan was secondary issue, this is hard to beat

 

[Ginseng]

Thanks for the table. It really makes things easy to see. By boost factor, you really mean how many extra 1.2V cell units are added. Is that right?

The only danger in extrapolating is that reality can depart significantly from calculations the farther you get from spec. But I can attest to the benefits of overdrive. I test fired a 12V 100W Osram (3,000 hr life) bulb this weekend at 15.5V and it was bright. I estimated output at somewhere between 4,000 and 5,000 lumens.

Wilkey

 

[java_man]

The boost factor is a multiplier (of the original voltage) by coincedence it also works... as you explained... as the number of additional 1.2 V cells.

 

[asdalton]

You can get some interesting trends from that data. For example, the filament life goes down with the 12th power of the applied voltage. If you make an Arrhenius plot from the filament life and the filament temperature, you get an activation energy of 8.6 eV (825 kJ/mol), which is very close to what you would expect from atomizing tungsten.