Runtime Plot for Maglight 3D - surprise, surprise.

[Quickbeam]

Just in case you were ever wondering what makes everyone love mags so much.... keep wondering.

50% in 1 hour. Most of the battery life is spent at below 50% output.....

Test completed with brand spankin' new Rayovac D cells.

 

[cognitivefun]

Re: Runtime Plot for Maglight 3D - surprise, surpr

great stuff, thanks.

 

[pedalinbob]

Re: Runtime Plot for Maglight 3D - surprise, surpr

WOW!

How very mediocre.

Bob

 

[Mags]

Re: Runtime Plot for Maglight 3D - surprise, surpr

I am guessing that is why most non flashaholics buy it. They dont care enough to change the batteries and just let it sit there, use it once a week, have it leak in a month, oops, buy another one and leave it on top of the mantel for show.

 

[enLIGHTenment]

Re: Runtime Plot for Maglight 3D - surprise, surpr

Isn't this pretty typical of alkaline incans, though? The only way around the rapid falloff of alkalines is to use a regulator, and Maglite is hardly the only incan builder guilty of ignoring electronics.

 

[NewBie]

Re: Runtime Plot for Maglight 3D - surprise, surpr

Would be interesting to see with a decent set of NiMH....

 

[UncleFester]

Re: Runtime Plot for Maglight 3D - surprise, surpr

What he said!

 

[3rd_shift]

Re: Runtime Plot for Maglight 3D - surprise, surpr

I hate to say this, but Rayovac has never made the best disposable batteries as far as I can remember.
The bulb in that light is a .85 amp unit in most cases.
It ought to be fine with nimh 11,000 batteries for 10 hours easy.

Just one problem.
magg recommends against using rechargeables for some wierd reason.
Every magg I ever used rechargeable nimhs and nicads in has had no problems at all.

 

[enLIGHTenment]

Re: Runtime Plot for Maglight 3D - surprise, surpr

2500mah Energizer D NIMH should give 3-4 hours at 83% of initial full brightness when using alkalines. See the data sheet:

http://data.energizer.com/PDFs/nh50.pdf

I don't have data for current technology 8-13 AH D cells.

 

[pedalinbob]

Re: Runtime Plot for Maglight 3D - surprise, surpr

This is interesting.

I have no idea as to the draw of the bulb, but if it were drawing 0.85amp, and fed by 18,000 mah bats...
Doesn't 1 hr 2 mins seem incredibly short? The dropoff seems so rapid.

Calling all the electrical gurus!

Bob

 

[Roy]

Re: Runtime Plot for Maglight 3D - surprise, surpr

Someone please explain to me how you run a flashlight at 83% of full brightness? I didn't know that the output of a Mag could be adjusted. I understand running a flashlight UNTILL YOU GET to 83% of max brightness...I just don't understand how to run AT 83% of max brightness.

 

[Rebus]

Re: Runtime Plot for Maglight 3D - surprise, surpr

The only way to run a Maglite is to start with
a 4D. With normal intermittent use, you can get
about 2 hours of use. At that point you simply
change to a 3cell bulb for about another 2 hours
of use. This bulb change usually produces
more light than the 4cell bulb did and I have
never had a bulb to pop doing this. You can even
step down to a 2cell bulb for an hour or so of
lesser light. This is an old cavers trick that
has been used for many years. They suggest that
you always carry an accurate voltmeter so that
you can maximize battery to bulb performance.
When I do it at home I simply stick a label on
the light to reminde me which bulb I'm using.

-Rebus

 

[treek13]

Re: Runtime Plot for Maglight 3D - surprise, surpr

[ QUOTE ]
3rd_shift said:
I hate to say this, but Rayovac has never made the best disposable batteries as far as I can remember...

[/ QUOTE ]
Actually, Rayovac D cells were the best at a .5 Amp rate, the best at a 3 Amp rate, and the second best at 1 Amp rate according to Silverfox's Alkaline Battery Shoot Out.
Rayovac's performance is clearly ahead of Energizer Max and Duracell, which is especially impressive considering their lower price.
Pat

 

[greenLED]

Re: Runtime Plot for Maglight 3D - surprise, surpr

[ QUOTE ]
3rd_shift said:
magg recommends against using rechargeables for some wierd reason.
Every magg I ever used rechargeable nimhs and nicads in has had no problems at all.

[/ QUOTE ]

In theory, that's because you're running the bulb at slightly lower voltage than they're rated for. This creates problems with the bulb (not all metal vapors resettle on the filament, IIRC) and reduces bulb life. I am not so sure it really matters for the lower-output Mag's bulbs. For example, I ran a 4D Mag on NiCads daily for 4 years and never had a bulb blow. I've swithched to NiMH now, and although my 4D doesn't see as much use anymore, I'm still on the same bulb. Maybe it's more of a problem in "real" HOLA's? /ubbthreads/images/graemlins/icon3.gif

 

[DarkLight]

Re: Runtime Plot for Maglight 3D - surprise, surpr

one test does not a study make..

Was this a new mag?
Perhaps you had corrosion issues..

the other battery life thread does not concur with your result at 1 amp draw...

 

[dat2zip]

Re: Runtime Plot for Maglight 3D - surprise, surpr

Running a filament = heat.

The hotter the filament the higher its resistance is.

Its a well know fact that a small drop in filament voltage reduces the filament temperature and thus the resistance drops. That means less light (obvious), but, also more current.

I believe this is a log function so it doesn't take much of voltage drop to dramatically increase the battery current. As the voltage continues to drop so does the rise in current exponentially speaking.

Probably at the 50% point I wouldn't be surprised if the battery current wasn't double that when the batteries were fresh.

Would be interesting to see the battery current over time vs light output.

Wayne

 

[enLIGHTenment]

Re: Runtime Plot for Maglight 3D - surprise, surpr

[ QUOTE ]
Roy said:
Someone please explain to me how you run a flashlight at 83% of full brightness?

[/ QUOTE ]

Nimh cells have a nominal voltage of 1.25v, which is 83% of the nominal 1.5 volts of a fresh alkaline. Ergo, any light designed for 1.5v cells will run at 83% brightness when using 1.25v rechargables.

 

[Quickbeam]

Re: Runtime Plot for Maglight 3D - surprise, surpr

Yes, this plot is pretty typical for an alkaline powered light...

 

[baylisstic]

Re: Runtime Plot for Maglight 3D - surprise, surpr

[ QUOTE ]
greenLED said:
[ QUOTE ]
3rd_shift said:
magg recommends against using rechargeables for some wierd reason.
Every magg I ever used rechargeable nimhs and nicads in has had no problems at all.

[/ QUOTE ]

In theory, that's because you're running the bulb at slightly lower voltage than they're rated for. This creates problems with the bulb (not all metal vapors resettle on the filament, IIRC) and reduces bulb life. I am not so sure it really matters for the lower-output Mag's bulbs. For example, I ran a 4D Mag on NiCads daily for 4 years and never had a bulb blow. I've swithched to NiMH now, and although my 4D doesn't see as much use anymore, I'm still on the same bulb. Maybe it's more of a problem in "real" HOLA's? /ubbthreads/images/graemlins/icon3.gif

[/ QUOTE ]

I was at fry's the other day looking for a xenon bulb to upgrade my stock mag 3d and I noticed the same thing as well. I used it in my mag with nimh batteries anyway and it worked fine. When I first saw the warning label, I thought maybe they meant you're not supposed to use it in a mag rechargeable. i.e. Mag charger. It's just a guess. But then again, they use different type bulb.

 

[asdalton]

Re: Runtime Plot for Maglight 3D - surprise, surpr

I disagree that a filament delivers more current as the voltage drops. I have run an incandescent lamp from a current-controlled power supply, and both the output and voltage increase with current. Less current gives less light. The I-V behavior is nonlinear but not enough to offset the qualitative trend that you would expect from a resistor.