Run Time Test for 2AA and 3AA LED Mini Maglites

This is my first post on the board, but I've been browsing for about a month now. I've recently purchased both the 3 watt LED 2 AA mini maglite and the 3 watt LED 3AA mini maglite. I agree with posters in other threads that the 3 battery lite is definitely brighter than the 2 cell one although I don't have a light meter and can't quantify the difference.

I believe I have some information to share that would be useful to Board members. I did some systematic run time calculations (although the brightness factor is clearly subjective since I have no light meter). No one, to my knowledge, has posted about the mini maglite runtimes with NiMH rechargeable batteries. Both worked just fine with NiMH cells. I tested both lights with 2000 mAH batteries (Lenmar) and then with 2650 mAH ones (Duracell).

The 2 AA cell mini mag appears to be regulated to put out a fairly stable light over time, as has been pointed out previously, and runs at a relatively constant brightness for quite a while. After a few hours it dims somewhat until it completely goes out without a "moonbeam," as has also been pointed out. For two runs at full charge using the 2000 mAH batteries I was able to run the light for 4 1/2 hours and 4 hr 45 mins, respectively For the 3 AA light I was able to get about 7 hours of light. However, around 2 1/2 hrs into the run time test, the light became less and less bright relative to the 2 AA mini mag. Thus, after 2 1/2 hrs, the 2 cell light was brighter than the 3 cell light until the 2 cell version went completely dark at about 4 1/2 hours. The 3 cell mini maglight became dimmer and dimmer until there was little useful light by 6 1/2 hours.

I repeated the same tests on both lights using the 2650 mAH Duracells. The 2 battery mini maglite went a full 5 hr and 50 minutes before it died. The light during that time was still reasonably bright and could be used outdoors and indoors easily. Thus, the useful light period (not a formal definition of run time to 50% brightness) before dying for this light was nearly 6 hours. The 3 battery mini maglite was still running and putting out dim, but usable light after 9 1/2 hours of operation. I was actually able to read newsprint easily in a darkened room at 9 1/2 hours on these batteries. The subjective crossover time when the brightness from the 3 cell mini maglite was about the same as the output for the 2 cell version was over 4 hours. Thus, for the first four hours, the amount of light emitted from the 3 cell lite was equal or greater than that from the 2 cell mini mag.

In summary, although I don't have a lot of LED light experience, I found the combination of run time and excellent 3 watt output from both of these lights to be just excellent. I'm very glad I own one of each and intend to operate them using the 2650 mAH Duracells

I did some a while back http://candlepowerforums.com/vb/showthread.php?t=132640

I did do a search, but must have missed this thread. Thanks, Chevrofreak, for doing this and setting me on to it. Your graphs are just great and generally match with my less calibrated and more subjective results. My 2AA runtime results are very close to what you found for the Duracell 2650 mAH batteries. According to your graphs, the drop off is precipitous at the 50% brightness mark, I see. So that would be the effective life of the flashlight on those batteries. Your 5 hr. 57 minutes is extremely close to my time of 5 hr. 50 mins.

For the 3AA battery model, I guestimated a runtime of over 4 hr until the light was approximately equal to that from the 2AA model, which is quite close to your more scientific data which lists the runtime to 50% as 4 hr 32 mins. The flat output curve until about 4 hrs is similar to my findings. However, we part company a bit at that point. I found that the 3AA mini maglight continued to give some usable light out to about 9 1/2 hrs, which is about 570 minutes long. According to your graph, the output dropped to a very minimum after about 5 1/2 hrs. My reading was that the output was brighter than that, out to around 6 1/2 hrs. It would be interesting to see a retest of these results.

In any case, the important point, I think, about this is that these two flashlights give considerable light for a relatively long runtime on Duracell 2650 mAH batteries. We can quibble about the exact duration of light output, but they represent, to me, excellent value for the runtime and light output. I think they both can have a place in one's flashlight inventory, but for different reasons. The 2AA model goes to almost 6 hrs, but the output drops precipitously. That's still a very nice runtime with excellent output. The 3AA model has greater output to about 4 hours and then drops much more gradually. If you are on a long walk and not sure how long the batteries will last (and don't have a spare pair), then the 3AA model might be better because you have a long period with gradually declining light.

Again, thanks for the excellent graphs and systematic runtime evaluation.