Battery life AAA

I recently aquired an ARC AAA and of course I had to waste a couple brand new duracell alkalines to investigate the battery life.

Test one: AAA went to 'moon' mode in 3.5 hours or at least was much much darker.
Test two: AAA in moon mode in 3 hours 20 min.

This is pretty good, but not the 5 hours to 50% brightness shown on the website.

I have the Premium.. does that make a difference?

Now.. I did the same thing to my ARC-AA and it ran for 9.5 hours before dimming to 'moon' mode, which is very close to the 10 hours quoted...

==>Premium LED shortens battery life (makes sense)?

I'm sure someone has the answer...

(from arc site):
Run Times

We conservatively estimate the run time with a good cell at around 5 hours. Although, your results may vary and many users report run times of over 6 hours. Every Arc model will continue to produce light after their rate run time but at less than 50% brightness. The Arc-AAA for example will still be producing a diminished output after 12 hours of use. With typical usage each cell will last several months. The Arc-AAA will produce a longer total run time than 5 hours if used intermittently.

Sun/Moon Mode

The Arc-AAA includes an electronic regulator circuit that helps maintain a more consistent output during the life of a battery. Compare this to conventional flashlights that more noticeably dim as the battery is depleted. The regulator in the Arc-AAA is a very compact design optomized for "partial" regulation. Please see further down in this FAQ for a more detailed description of regulation.

Basically, "Sun" mode is the bright operation of the flashlight and "moon" mode is the dim light produced by the light when the battery is nearly dead. When stating run time for our lights, we list the "sun" mode length for a given battery type. The Arc-AAA is capable of producing about 5 hours of sun mode.

With only 40% of the remaining capacity left in the AAA battery, the Arc-AAA will still be producing about 80% of it's original brightness.

The transistion from sun to moon is fairly smooth on the Arc-AAA with most battery chemistries and you may not notice it very easily. With alkaline cells, it is not an abrupt change.

Not sure if this is what you're seeing, but intermittent use is supposed to give you longer battery life than a single continuous run. I don't think the advertised runtimes are based on intermittend use, though.

It's more likely that the brand of battery you are using is making a difference. People have reported significant differences in runtime with different brands. What kind are you using?

The other thought I have is that the design was recently tweaked (including the circuit design) to fix a problem. Perhaps the tweak sucks up more juice?

The premium should not take any more power than the standard. They both have the same brightness, it's just the tint that differs, so you should expect identical runtime.

Anyone else have thoughts about what's happening here? I'm expecting an Arc AAA-P as a warrenty replacement and hope that this isn't a problem with all new Arc AAA-Ps.

- Russ

There's a bunch of factors.

- battery.
- led.
- circuit.

I actually have 1-Arc AAA that runs brightly for almost 7-hours before moon mode.

3.2-3.5 hours sounds too low for a normally functioning AAA, unless the recent circuit changes shortened it. Mine runs for 7+ hours.

[ QUOTE ]
r2 said:
It's more likely that the brand of battery you are using is making a difference. People have reported significant differences in runtime with different brands. What kind are you using?

- Russ

[/ QUOTE ]

I'm using brand new duracell alkalines (like I said in the original post).

I expected 5 hours and got 3.5. The beam is very bright and good color...whiter than my AA. This is an AAA premium, designation ARC-P on the side. It's a great light, but I was hoping for a longer runtime...

I'm jealous of the 7 hour folks.

klatmann, if you have a way to measure the battery current, that might tell something. 3.5 hours is enough below normal runtime that you might inquire with Peter about a warranty exchange.

[ QUOTE ]
paulr said:
klatmann, if you have a way to measure the battery current, that might tell something. 3.5 hours is enough below normal runtime that you might inquire with Peter about a warranty exchange.

[/ QUOTE ]

Okay, so you're saying that the cuurent draw of the head is proprtional to the light output?
Or that the remaining battery current is the inversely proportional to light?

I'm not sure what the circuit does, but I suppose either one would show the moon mode transition better than the most accurate measuring device in the world. (my eye /ubbthreads/images/graemlins/tongue.gif )

I have to buy some new batteries now /ubbthreads/images/graemlins/icon23.gif

The current draw is inversely proportional to the runtime. The light output depends on a combination of the current draw, the circuit efficiency, and the LED efficiency which varies according to the current. The circuit takes the 1-1.5 volts from the AAA cell and steps it up to the 3.6 volts or so that the LED needs to run at full brightness. It's supposed to be around 80% efficient but that varies according to a number of factors.

Moon mode in an AAA is not like a dimmer version of normal mode. It's extremely dim, not much brighter than the glow markers on a watch dial. It's only useful in basically absolute pitch blackness. It's normal for an Arc AAA to dim considerably during its runtime as the battery voltage declines, but that isn't moon mode. Note that if an AAA goes into moon mode, you can turn it off and let the battery rest for a minute or two, then turn it back on and get normal mode again for a while.

Measuring the current draw would just show if your AAA is using more current than normal with a new battery.

[ QUOTE ]
paulr said:
The current draw is inversely proportional to the runtime.

[/ QUOTE ]

Yes, but is it the same through the whole lifetime of the battery? Does the moon mode consume less current?

I'll check it this weekend...

Since it was brought up.. how much current _should_ the AAA draw on a new alkaline? Someone have a range?

i measured 100 mA on mine

It should draw between 200-300 mA.

klattman, when you are ready...

Peter

Mine draws 250mA. /ubbthreads/images/graemlins/smile.gif

If you take the datasheet: http://www.duracell.com/oem/Pdf/MX2400.pdf and look at the chart that says Typical Ultra AAA Discharge Characteristic and look at the blue line, the battery will supply 250mA (0.25) for just over three hours before dropping to 0.9V (basically discharged). As the battery voltage drops, the switching regulator will draw more current, which will lead to more rapid depletion. So your moon mode at just over 3 hours sounds about right, from the battery perspective.

As I read the ARC website, I too would get the impression that the regulated output (full brightness) lasts for 5 hours, then goes into moon mode.

For those who's flashlights draw 100mA, how old are they?
For those who's flashlights draw 250mA, how old are they?

Now, if you go look at the AA, http://www.duracell.com/oem/Pdf/MX1500.pdf, you'll see it will last to near the 9 hours at 250mA.

Also see this old thread:


Title: Arc-AA nearing production...

The last post by Dave Wright asking about the same issue you are talking about is left unanswered.
/ubbthreads/images/graemlins/icon23.gif

Repeat: The Arc-AAA is rated for 5 hours to 50% brightness with a good battery. That means the light will be half as bright in 5 hours.

Peter

I carry my Arc-AAA with me all the time. I throw it in my pocket with my comb and my little Buck pocket knife. I don't baby it because it is built to be very durable. It's not very bright. The beam has a purple cast even though it is a premium. I use it probably several time a day at home, to see in dark places at work. When my wife and I drive to work separately I use it to flirt with her and let her know that I am there and I care. I let my grandson play with it in the bathtub to create a glow in the water if I turn the light off and it becomes a special occasion with Grandpa. It has never let me down. When the battery gets weak, there is still light to finish whatever I am doing and find my way to a new battery.
I can get a replacement battery at any 7-11 or gas station or Quick Mart. I usually buy the AAA's at Costco paying about 9 bucks for 24 batteries. I love this little light and really don't give a damn if the battery lasts for 2 1/2 or 3 1/2 or 5 hours before dropping out of regulation for all of the reasons mentioned above.
Thank you Peter for making such a fine quality flashlight that is so small and convenient to carry!

TerryF

[ QUOTE ]
NewBie said:
If you take the datasheet: http://www.duracell.com/oem/Pdf/MX2400.pdf and look at the chart that says Typical Ultra AAA Discharge Characteristic and look at the blue line, the battery will supply 250mA (0.25) for just over three hours before dropping to 0.9V (basically discharged). As the battery voltage drops, the switching regulator will draw more current, which will lead to more rapid depletion. So your moon mode at just over 3 hours sounds about right, from the battery perspective.

As I read the ARC website, I too would get the impression that the regulated output (full brightness) lasts for 5 hours, then goes into moon mode.

For those who's flashlights draw 100mA, how old are they?
For those who's flashlights draw 250mA, how old are they?

Now, if you go look at the AA, http://www.duracell.com/oem/Pdf/MX1500.pdf, you'll see it will last to near the 9 hours at 250mA.

Also see this old thread:


Title: Arc-AA nearing production...

The last post by Dave Wright asking about the same issue you are talking about is left unanswered.
/ubbthreads/images/graemlins/icon23.gif


[/ QUOTE ]

Yep.. I said that my AA last 9.5 hours before moon mode.

OTOH, my AAA measures 340mA with a new duracell alkalike (1.6V), but is not steady and slowly drops...
and an older battery gives me about 200mA (1.13V).
I did not have a battery that could produce 'moon' mode because I find that once I get to moon mode, I need a stronger battery to get the circuit started (i.e. I cannot restrat the light with a battery once it is in moon mode right away.)

If I had the patience to do another 5 hour test I could monitor the current and see what happens, BUT it appears that, given what Peter and others said about the current draw, that my light is fine.

I suppose the 50% brightness is hard to determine by eye and I may have been fooling myself.

[ QUOTE ]
javafool said:
I love this little light and really don't give a damn if the battery lasts for 2 1/2 or 3 1/2 or 5 hours before dropping out of regulation for all of the reasons mentioned above.
Thank you Peter for making such a fine quality flashlight that is so small and convenient to carry!

TerryF

[/ QUOTE ]

I didn't speak ill of ARC or Peter, just trying to determine if my light was okay. /ubbthreads/images/graemlins/ohgeez.gif

[ QUOTE ]
klattman said:

I didn't speak ill of ARC or Peter, just trying to determine if my light was okay. /ubbthreads/images/graemlins/ohgeez.gif

[/ QUOTE ]

I didn't mean to come off too cranky about this thread because I really am interested in battery consumption and flashlight performance. It just seems some people are holding Peter's feet to the fire in minute detail for every claim he makes.

I ask in the New switch design thread about backward compatability and nearly started a Arc revolt. Your question about runtime was valid and I didn't mean to attack you for your question. I probably overreacted but Peter and the Arc group work harder at customer satisfaction making things right for their customers than any other manufacturer I have dealt with and there seems to be more negativity pointed in their direction lately that I think they deserve.

TerryF