Overdriving the Mag2AA bulb in the name of science

[KevinL]

Yeah, someone had to do it [img]/ubbthreads/images/graemlins/smile.gif[/img]

Besides after the LED drop in upgrade, there is no turning back anyway, so I might as well have some fun with the bulb. What I did was hook it up to a battery pack of 4 x AA NiMH hot off the charger, the cells still warm, registering 5.55V for the entire pack in its holder.

The Mag 2AA bulb was already somewhat blackened, it's terrible how even a fresh bulb can turn black when it's not even through its first set of Duracell AA alkalines.

So what happens? The bulb registers 400mA on my DMM, and lasts for around 20 seconds, but it's frighteningly bright. About 5 times as bright as it usually is. I'm thinking, it can do that? Then suddenly, no more light. I switch the DMM to continuity check mode and get no beep, but I get a digital reading, surprisingly. Normally, the DMM just says "1" when there's no connection. I switch it to 2000 ohm resistance mode, and I find out I now have a nice 317 ohm resistor. It still conducts some current, but like I said, it packs some considerable resistance.

[eebowler]

Odd. I can't figure out how the fillament is still connected after such a test.

Thanks for the test Kevin.

[Nerd]

Hmm... maybe we can run 2/3 AAs in the minimag? [img]/ubbthreads/images/graemlins/grin.gif[/img]

[KevinL]

[ QUOTE ]
eebowler said:
Odd. I can't figure out how the fillament is still connected after such a test.

Thanks for the test Kevin.

[/ QUOTE ]

No problem. [img]/ubbthreads/images/graemlins/smile.gif[/img]

Yeah, the filament still conducting some miniscule current but not lighting up is quite a mystery. When I put my 1W Q4H Lux in series with it, the Lux lights up - very dimly, but it lights up, so it can't be the DMM.

[4x4Dragon]

[ QUOTE ]
KevinL1 said:
Yeah, someone had to do it [img]/ubbthreads/images/graemlins/smile.gif[/img]

Besides after the LED drop in upgrade, there is no turning back anyway, so I might as well have some fun with the bulb. What I did was hook it up to a battery pack of 4 x AA NiMH hot off the charger, the cells still warm, registering 5.55V for the entire pack in its holder.

The Mag 2AA bulb was already somewhat blackened, it's terrible how even a fresh bulb can turn black when it's not even through its first set of Duracell AA alkalines.

So what happens? The bulb registers 400mA on my DMM, and lasts for around 20 seconds, but it's frighteningly bright. About 5 times as bright as it usually is. I'm thinking, it can do that? Then suddenly, no more light. I switch the DMM to continuity check mode and get no beep, but I get a digital reading, surprisingly. Normally, the DMM just says "1" when there's no connection. I switch it to 2000 ohm resistance mode, and I find out I now have a nice 317 ohm resistor. It still conducts some current, but like I said, it packs some considerable resistance.

[/ QUOTE ]

i did 1 AA and 2 N cells one time. very white!!! and bright.

[markdi]

the vaporized metal is probably coating the whole inside of the bulb and providing a high resistance current path.

I thought mini mags ran at about 300 ma so your current readings do not seem that high.

[fivemega]

I have done once with a 14500 Li-ion and a dummy AA
It was bright.

[bwaites]

One 3 volt lithium, and 1 1.5 volt lithium works great! Very bright.

Bill

[markdi]

the combination of 50 percent higher voltage and lower internal cell resistance would make me think that they would be flashbulbs.

[KevinL]

[ QUOTE ]
markdi said:
the vaporized metal is probably coating the whole inside of the bulb and providing a high resistance current path.

I thought mini mags ran at about 300 ma so your current readings do not seem that high.

[/ QUOTE ]

Wow, thanks for the explanation. Just for comparison's sake, when on the Duracells, the MiniMag AA bulb ran 290mA at 3V nominal, or 0.87W. Of course, 400mA at 5.55V is 2.22W.. [img]/ubbthreads/images/graemlins/hahaha.gif[/img]