by Jenab » Wed 17 Nov 2010, 20:09:00
This discussion is about the results of actual tests done by posters on how long their disposable batteries last. If you test a rechargeable battery, be sure to say it is rechargeable and how long it lasted on a single charge. The purpose of this discussion is to see for ourselves which battery brands are the best made, and which ones come up short, and in so doing help Peak Oil Forum users spend their money wisely when buying batteries. Or, if longterm storage space for batteries is at a premium, we can select the longest lasting batteries rather than the ones having the best money value.
I'll go first with a few tests of my own, just to give everyone else some idea of what information should be included. Of course, there will be circumstances of which we might not be aware. For example, a given battery might have been mistreated by being improperly kept in a humid environment or exposed to high temperatures (above 100°F), which might have leached some of the chemical energy out of the battery while it was still in the store package. To overcome that kind of problem, we'll just do lots of tests.
For my first time-to-drain tests, I purchased six CREE Q5 SA20 LED flashlights, said to emit 270 lumens (with a fresh battery) from a single LED. The ambient temperature during the tests varied from 70°F to 85°F, but staying in about the middle of that range most of the time. For each test, all of the flashlights being used were turned on within a span of 10 seconds.
Most people like to have a bright flashlight, but a fresh battery will only supply that bright light for a short while (about three hours with these LED flashlights), after which time the battery will have weakened to the point where the light output would be judged unsatisfactory and the battery replaced.
However, if you were stuck in a dark cave, even the puny glow of a depleted and most inferior battery would be much better than no light at all. In the kind of survival situation in which every bit of light is critical, you would not swap old batteries for fresh ones as long as the old battery was of any use at all.
And there a situations in which you might want a weak battery in your LED flashlight to emit only a weak beam. Such as if you were committing a burglary. Alkaline batteries will go on and on for quite a while at a reduced voltage, but what that sustained "tired" voltage is varies among battery brands.
Subjective judgments regarding weak flashlight beams are, in order of decreasing brightness:
* Inspect one's near vicinity, out to about 20 feet
* See one's own shoes with the flashlight held at shoulder height
* Read one's own watch with the flashlight a foot away
Battery Test #1.
This test was carried out in early November 2010. Tests on the following three alkaline batteries were done simultaneously:
1. Dollar General Home, AA, expiration 2015.
2. Dollar General Everyday, AA, expiration 2014.
3. Duracell Coppertop, AA, expiration 2013.
The main use times, bright to fairly dim, were DG Home: 3 hours, DG Everyday: 3.5 hours, and Duracell Coppertop: 5 hours.
Following the main use times, the Duracell Coppertop battery created a much brighter light than the DG Everyday Battery, which in turn was considerably brighter than the DG Home battery.
24 hours into test. The DG Home battery's residual glow is laughably feeble. The DG Everyday battery is a little better, but nothing to brag about. The Duracell Coppertop battery is by far the brightest of the three, though of course it was nowhere near as bright as it was at the start of the experiment.
31 hours into test. The DG Home AA battery is making feeble ghostly glow, not really useful, not quite extinct. The DG Everyday AA battery produces light sufficient for user's immediate surroundings in otherwise absolute darkness. The Duracell Coppertop AA battery, strongest of the three, makes a weak but serviceable beam.
47 hours into test. All batteries are at least somewhat weaker, but the Duracell Coppertop has suffered the biggest fall during the last 16 hours. Although it remains the strongest of the three batteries, the difference is now less than it was. The beam from the LED flashlight with the Coppertop battery is now at the "useful for immediate vicinity in total darkness" level.
78 hours into test. Both of the Dollar General batteries have become so weak that the light from their LED flashlights is useless for anything other than checking your watch (hold the LED real close). The Duracell Coppertop battery is still making a relatively brighter light that is sufficient to see your shoes in total darkness with the flashlight held at shoulder height.
About 90 hours into the test, all three of the batteries completely died, with no glow whatever coming from the flashlight LEDs.
The relative ranking of these three batteries is
1st place: Duracell Coppertop
2nd place: Dollar General Everyday
3rd place: Dollar General Home
Battery Test #2.
This test was carried out in mid-November 2010. Tests on the following three alkaline batteries were done simultaneously:
1. Dollar General Energy Super Plus, AA, expiration 2012.
2. Duracell Coppertop, AA, expiration 2014.
3. Energizer Max, AA, expiration 2014.
By 1h 30m into the test, the DG Energy Super Plus battery was already weakening, having become substantially weaker than either the Duracell or the Energizer battery.
By 6 hours into the test, it appears that the Duracell Coppertop battery is holding up better than the Energizer Max battery. Although both batteries have dimmed considerably, the Energizer has dimmed the more. The light from the DG Energy Super Plus battery is already quite feeble, by far the weakest of the three.
24 hours into test, the relative situation hasn't changed except that the difference between the Duracell Coppertop and the Energizer Max is greater than it was before. The Duracell Coppertop is by far the better battery. The Dollar General Energy Super Plus battery remains, of course, the very worst.
30 hours into test. The LED powered by the Energizer Max has faded so much that it is now equally bright with the Dollar General Energy Super Plus battery. The Duracell Coppertop battery LED outshines both of the other two.
64 hours into test. The Dollar General Energy Super Plus battery is dead and in the trash can. The Energizer Max is still putting out a "see your shoes in total darkness" feeble glow. The Duracell Coppertop is producing a somewhat brighter "inspect your near surroundings" weak beam.
72 hours into test. The Energizer Max is down to "check your watch in total darkness," and the Duracell Coppertop, still slightly brighter, has fallen to "see your shoes in total darkness."
80 hours into test. The Energizer Max and the Duracell Coppertop are producing about equally dim glows from their LEDs. You could check your watch with either of them.
88 hours into test. The Duracell Coppertop battery is dead. The Energizer Max battery continues to make the LED of its flashlight glow faintly. You could probably check your watch by it in total darkness.
92 hours. The Energizer battery is dead. Test over.
The relative ranking of these three batteries is
1st place: Duracell Coppertop
2nd place: Energizer Max
3rd place: Dollar General Energy Super Plus
The reason for the #1 ranking of the Duracell Coppertop is that its LED light was significantly brighter than that of the Energizer Max through most of the test. The Coppertop had a much higher integrated light output.
Jerry Abbott