Can light voltage for MR16 Help!

[debitthis]

So far I've already choped, ground, and JB Welded my D cell Mag-lite. (That was the fun part).
My battery and bulb are troubling me. I was playing with hooking up the bub to the battery and after 5 min. the bulb, Philips 20W 12v halogen, stopped working. The battery is a sealed Lead-acid battery and the main wording on the label says that it is 12V 5.0 Ah.

However the fine print says that the voltage regulation is 13.6-13.8v | 0.75A for standby and 14.5-14.9v | 1.5A for cyclic use.

Did this kill my bulb and I need to get a different battery, or was the bulb just bad?

 

[Packhorse]

Those voltages are the charging voltages.. If you want to charge it then supply 14.5-14.9 volt @ 1.5amp. If you were to use it as a battery backup for a alarm them it would need a constant 13.6-13.8 volts across it.
When fully charged it should have 13 volts or so. The bulb should last thousands of hours.
I have yet to have a bulb die on me from anything but shock or water leaks.
Some people overdrive thier MR16 bulbs with 12 1.2 volt cells giving a nominal 14.4 volt output (that could be over 16volts on a fresh charge).
This will shorten your bulb life but even if its only 10% of rated life so what? They are still one of the cheapest bulbs you can get for a dive light.

 

[debitthis]

Thanks! That is a load off my mind. Now on to molding PVC.

 

[Pathfinder]

Some people overdrive thier MR16 bulbs with 12 1.2 volt cells giving a nominal 14.4 volt output (that could be over 16volts on a fresh charge).
.

That's exactly what I found on 12 x c cells rated at 1.2 volts each.

Dave

 

[diveAK]

I overdrive my can light with 14 1.2 V NiMH batteries, and with a 50 W bulb it powers it to output roughly 65 W of light... and a great charge on the battery pack is 19.5 V

 

[Packhorse]

How long is the bulb life @19.5v? How many amphour is the battery pack and whats your burn time?
I am currently working on a 12 D cell nicad 5000\mAmp pack.
The battey compartment will be totaly sealed off with no access. And I was thinking about filling it with oil to ensure no leakage.
Any thoughts?

 

[diveAK]

Depends on what you mean by bulb life... with a 50 W bulb it goes about an hour and 15, and with a rest time of an hour its good for another hour dive. With a 35 W bulb Ive been on a 2+ hour dive and it didnt fade at all. The actually lifetime of a bulb? I break them before they ever ran out (my lense imploded last dive at 150') because the light body usually cracks a little while tighenting it down so there is no leakage. They batteries are 10000 mAh (expensive, but worth it).

 

[Charlie99]

How long is the bulb life @19.5v?

http://www.gilway.com/pdf/appl-tungsten.pdf

GE has similar data ---- light is approximately proportional to the 3.6 power of the voltage and bulb life is inversely proportional to the 12th power of voltage.

The true nominal voltage of the MR16 bulbs is 12.0V, unlike "12V" automotive bulbs.

 

[Packhorse]

How do you charge it?

The reason I chose Nicad is they are easyier to charge than NIHM and cheaper.

 

[diveAK]

Reinforced the lense after it imploded, and filled up some of the empty space in the head and it went down to 170' last dive, only a little leakage in the head... working to fix it!