Final: iPod mini battery tests | iLounge Article

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Final: iPod mini battery tests

The results are in: after last week’s initial tests of the iPod mini’s battery performance, we noted that we were cautiously optimistic that Apple had quietly remedied certain issues of concern to iPod users, most importantly accurately estimating the mini’s duration of continuous playback. Mid-week, we updated our findings to reflect surprising intermediate results, and now after a series of eleven tests, we have reached several conclusions that might interest potential iPod mini buyers.

Three Types of Tests

We performed a total of three types of tests on the iPod mini, two of which were documented in our previous reviews and report, and one of which is new.

Type A consisted of a full recharge and discharge of the iPod mini’s battery without user intervention or backlighting, using “shuffle songs” mode, no equalizers, and 50% volume with headphones attached.

Type B was identical to Type A except that “shuffle songs” mode was disabled and the iPod was instead allowed to play continuously in sequence through its song list. We did not expect to see a significant difference between the iPod mini’s performance on Types A and B, because in both cases the mini was given complete control over the caching of songs, regardless of the order in which they were played back.

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Our third test was an attempt to duplicate results achieved by Walter Mossberg of the Wall Street Journal, using the same testing mechanism he tried with two pre-production iPod minis some weeks ago. (Thank you, Mr. Mossberg, for contacting us to share your testing conditions.) Like our Type A test, Mr. Mossberg used shuffled playback, but he also set the iPod minis on 75% volume and turned the Vocal Booster equalizer setting on, each of which adds to the strain on the battery.

Type A Test Results

For reasons further described below, after printing our intermediate findings, we concentrated the majority of our remaining testing efforts on Type A-style tests. Initially, the iPod mini had failed to meet Apple’s estimates in this type of testing, falling below six hours on its first test and barely exceeding that on its second.

However, after each Type A test, we saw that the iPod mini’s performance improved, eventually exceeding Apple’s estimates by over an hour and a half in three successive tests. In fact, the mini eventually delivered ten hours and ten minutes of continuous playback, coming within half an hour of Walter Mossberg’s ten hour and forty minute performance.

  • Test 1: iPod mini hits 10% at 5 hours playback, 0% at 5:20, dies at 5:45.
  • Test 3: iPod mini hits 10% at 5:33, 0% at 6 hours, dies at 6:19.
  • Test 7: iPod mini hits 10% at 8:55, 0% at 9:22, dies at 9:39.
  • Test 8: iPod mini hits 10% at 8:43, 0% at 9:23, dies at 9:46.
  • Test 9: iPod mini hits 10% at 9:21, 0% at 9:54, dies at 10:10.

For comparison’s sake, we ran a Type A test on a third-generation iPod that had been discharged and recharged over the course of many months, and found that it came within ten minutes of Apple’s estimated eight-hour battery life:

Test 5: 3G iPod hits 10% at 7:14, 0% at 7:29, dies at 7:50.

By Test 7, and continuously through Test 9, the mini’s battery appeared over time to outperform the third-generation iPod under similar (though not scientifically identical) Type A testing conditions. We had seen similar better-than-3G results for the mini in Type B tests, but were not sure whether the mini and 3G iPods were behaving truly differently, or whether the iPod mini’s battery was still being broken in.

Our working assumption at this point is that after approximately five discharges and recharges of the battery, the iPod mini is capable of consistently delivering power performance near or exceeding Apple’s estimates. Prior to that, we assume, it may not charge or discharge as efficiently or predictably, yielding the discrepancy in results we saw during our first four tests. We had not changed any of the testing conditions or the audio library on the iPod mini, or used the device for leisure listening during our test period. Therefore, holding everything else equal, we can only assume that the performance improvements came from an increasingly broken-in battery.

Type B Test Results

After printing our intermediate Type B findings, in which the iPod mini exceeded Apple’s estimates by approximately one or two hours, we did not continue to run further Type B tests. Though we continue to caution readers that Type B does not represent realistic usage conditions for typical iPod users, the use of smart playlists and other non-interactive forms of continuous audio playback will yield relatively impressive performance times such as these.

  • Test 2: iPod mini hits 10% at 7:50, 0% at 8:49, dies at 8:58.
  • Test 4: iPod mini hits 10% at 8:42, 0% at 9:40, dies at 9:56.
  • Test 6: iPod 3G hits 10% at 7:10, 0% at 7:30, dies at 7:48.

Even nearly fresh out of the box, the iPod mini outperformed a well-primed 3G iPod by over an hour on its first test, and over two hours on its second. We believe that battery priming is most likely the reason our comparative test of the third-generation iPod yielded results consistent with Apple’s stated estimate, and statistically almost identical to the 3G iPod’s performance in Type A testing.

We can only assume that another run of this test, slanted as much as it is towards battery conservation, would now yield results matching Walter Mossberg’s best time, given that our iPod mini’s battery has had additional burn-in time since we ran these Type B tests days ago. But instead of running this easy test, we decided to run Mr. Mossberg’s more demanding test and see how our mini would perform.

Walter Mossberg Test Results

Our final two tests of the iPod mini duplicated the test conditions used by the Wall Street Journal’s Walter Mossberg on two pre-production iPod minis sent for review by Apple. For reference, Mr. Mossberg achieved three scores across two iPod minis: 7:46, 9:15 and 10:40, or two to nearly five hours better than our first Type A test.

We administered our tenth total test at the relative peak of the mini’s performance, following Test 9’s ten-hour, ten-minute Type A result, and we were not expecting a substantial difference when this test was run. But we were surprised.

Test 10: iPod mini hits 10% at 6:28, 0% at 7:08, and dies at 7:27.

Puzzling? Yes. We were going to call an end to our testing after ten successive runs, but we had to run one more test to see whether our results necessarily varied that dramatically from Mr. Mossberg’s findings. And they did.

Test 11: iPod mini hits 10% at 6:32, 0% at 7:04, and dies at 7:19.

When Test 10 had concluded, we wanted to believe that the iPod’s battery was merely experiencing occasional hiccups. After Test 11, that possibility became harder to believe. These certainly weren’t the positive notes we had hoped to end our testing on, but we couldn’t ignore the results once we had them.

Conclusions

After more than a week of sustained iPod mini battery testing, we’ve come to three conclusions. First, after nine tests on the mini, we averaged approximately eight hours and ten minutes of music playback before battery death, a respectable number. While this duration may not compare favorably with certain competing products, it exceeds the battery life Apple advertised for the mini, as well as what we squeezed out of the 3G iPod, surely positive findings for potential and current mini owners.

Second, after seeing the mini’s battery performance improve after almost every test, we feel as if there’s no cause for alarm regarding its day to day performance, and in fact there’s reason to believe that the typical user will see better and better results for a week or more after opening the box. While concerns remain over the battery’s long-term lifespan, with 300-500 charge cycles (or approximately 18 months) of performance expected from a Lithium-Ion power source, all we could ask for - or perhaps expect - from the next iPod is a battery that’s easier for users to replace.
 
Third and finally, though we were disappointed that our mini failed twice to duplicate Walter Mossberg’s results under nearly identical conditions, we’re not going to worry about it. Our current working assumption is that the typical iPod mini will exhibit performance peaks and valleys before falling into steady output around or slightly surpassing the eight-hour mark under optimal conditions, falling somewhat sharply if users make significant use of the hard disk, backlight, volume, equalizer and controls, in descending order of importance.

Of course, we would hope that the next-generation iPod includes significantly improved battery performance, but if the iPod mini is any indication, Apple’s already on the road towards that goal. For users who want to relax with eight to ten hours of continuous music - like we do, especially after more than a week of monotonous iPod battery testing - the iPod mini will likely deliver all it promised, and probably more.

Jeremy Horwitz is a consumer electronics fanatic who practices intellectual property law in his spare time. His recent book, Law School Insider, has been called the “best book about law school -ever,” and he continues to contribute to Ziff-Davis electronic entertainment magazines.

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Comments

1

Ipod mini, is cool, yet doesn’t worth the 250$.
Add another 50 and get a full 15 GB one.

      Much better!!!

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 6:22 AM (CST)

1

it would be interesting to know what bitrate/format these tests base on…that’s probably the reason why you guys couldn’t duplicate Mr. Mossberg’s results…

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 6:30 AM (CST)

1

<<Ipod mini, is cool, yet doesn’t worth the 250$.
Add another 50 and get a full 15 GB one. >>

Wow, you’re just an Einstein for figuring that one out on your own aren’t you?  I’m glad you set us all straight on that one, I never would have figured it out on my own otherwise.  Did you ever stop to think that just maybe people are buying the mini for reasons other than simply the HD capacity?  Like the smaller size, choice of 5 colors, superior navigation, superior battery life, etc?

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 6:41 AM (CST)

1

Sounds like someone just bought a mini and is trying to justify the expense….

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 8:18 AM (CST)

1

Fed up with an extra 50 bucks gets you more GB argument being repeated ad nauseam.

If everyone was a card carrying, sandal wearing, overweight geek you might be right.

Fortunately the world isn’t like that. Well at least mine isn’t. Chic and convenience count just as much as all those pre-orders prove.

Oh, I don’t have an iPod mini yet so no need to justify anything.

Just wait till the internals of the iPod minis are integrated into mobile phones. they have got to be looking at that in the long run.

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 9:14 AM (CST)

1

Not to be annoying or anything but I have the 20gb 3rd gen and a new silver mini and setting aside the natural “honeymoon period” the mini is superior in every way but storage.  I only have 800 songs that I listen to so storage is no problem at all.  I pop that bad boy in my shirt pocket, forget about it and go!  I also have an original 5gb and a 10gb second gen…yes 4 iPods but I love them each in thier own unique way.  Again, the mini takes the cake.  I like the display font better, navigation better, sound quality sounds better (more bass imho), build quality, and the size obv is better. The mini hits the sweet spot and is well worth the 250.  PS. It works fine with the inMotion speakers. (not that there would be any reason for it not working but I thought I would let you know.)

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 9:23 AM (CST)

1

Seriously, all these people than go on and on about go 50 higher and buy a iPod. Do you think people dont conisder this? Maybe people want superior looks (in their opinion), maybe people want superior buttons. I mean, people seem to take offense to people who are getting an iPod mini. Geez…

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 9:41 AM (CST)

1

I spent $50 more on 15G and happy with it…

Running out of hard disk space though

forget about $250 but 4G is not enough clearly

 

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 10:33 AM (CST)

1

You may want to reconsider your testing methods (that is, continually draining the battery until the iPod shuts off.)  It is a well known fact that deep discharge drastically alters battery life.  From http://www.nexergy.com/Reflib/Lithium_Ion_FAQ.html, “over discharge… will cause irreversible chemical changes to the cell. These charges will reduce the retained capacity and cycle life of the battery.”  Since most consumers are used to NiCad batteries which lose capacity due to a memory effect, perhaps educating them on the proper care and maintenance of Li-ion cells would do more to alleviate the battery woes in iPods than anything else.

More information can be found at:
http://en.wikipedia.org/wiki/LiIon

JDB

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 10:59 AM (CST)

1

i’d rather pay $50 less then the 15 gig and get a smaller ipod. i really like it.  i also really like the clickable wheel, although its tempting to want to use the clicks as a navigation tool.

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 12:20 PM (CST)

1

“It is a well known fact that deep discharge drastically alters battery life”

Yep. But electronic devices can be designed that do not allow a Li-On cell to damage itself. If the iPod is well-designed, then a “deep discharge” is not really a *full* deep discharge - the iPod will stop draining the cell once the voltage dips below a dangerous threshold.

Of course, if it’s not well-designed, then it would damage the cell to drain it to exhaustion, repeatedly.

http://www.buchmann.ca/Chap5-page3.asp

“Similar to the lead acid battery, the Li-ion battery prefers shallow over repetitive deep discharge cycles. Up to 1000 cycles can be achieved if the battery is only partially discharged. Besides cycling, the performance of the Li-ion is also affected by aging. Capacity loss through aging is independent of use. However, in daily use, there is a combination of both.”

“The Li-ion typically discharges to 3.0V/cell. The spinel and coke versions can be discharged to 2.5V/cell. The lower end-of-discharge voltage gains a few extra percentage points. Since the equipment manufacturers cannot specify which battery type may be used, most equipment is designed for a three-volt cut-off.

Caution should be exercised not to discharge a lithium-based battery too low. Discharging a lithium-based battery below 2.5V may cut off the battery

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 12:47 PM (CST)

1

Will you idiots stop the stupid ‘for only $50 you can get more HDD’!!!
If you’re going to use that excuse, why not just get a Nomad Zen?  Not only does it have more HDD it’s also cheaper?

No?  Dont like the Zen?  Then STFU!

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 8:27 PM (CST)

1

What is the problem with you guys is just $50 dollars GET OVER IT! ok
i know the 15gb has more space but the mini has the looks and is the best thing ever made so far from APPLE and i love it i have 400 songs in it including Hilary duff, Linkin Park, Aaliyah and a whole lot more and you guys are saying that is not much space you guys are crazy how much songs do you need you are not going to listen to all of the are you? well i guess you are not so stop it@

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 8:35 PM (CST)

1

its small. i cant afford 50$ extra. its nice. i can run with it. I LOVE IT!

Posted by Dennis Lloyd in Irvine, CA on March 2, 2004 at 10:04 PM (CST)

1

“...i have 400 songs in it including Hilary duff, Linkin Park, Aaliyah and a whole lot more…”

well, you had a point until you went and admitted that.

Posted by Dennis Lloyd in Irvine, CA on March 3, 2004 at 11:43 AM (CST)

1

Well my mini was a birthday present. I know it’s less space but do u really need 3,700 songs or even 10,000. You can only listen to 1 song at a time. My mom bought me the 20GB one first and I asked her to take it back. $400 for a TOY is just TOO MUCH, I don’t care what it can do. And as for hard drive space, just get a laptop, it’s already portable.

Posted by Dennis Lloyd in Irvine, CA on March 3, 2004 at 2:48 PM (CST)

1

“...And as for hard drive space, just get a laptop, it’s already portable…”

I don’t know about you but I wouldn’t walk around with my laptop running.  In fact the comparision between iPod (of any size) and laptop is just plain stupid.

Posted by Dennis Lloyd in Irvine, CA on March 3, 2004 at 7:00 PM (CST)

1

christopher ch - dude, bad music collection…

tifah - I currently have 5,766 songs on my 30gb (almost full!)...of course you can only listen to one song at a time and of course I’m never going to listen to all those songs non-stop (it would take 18 days)!  but that’s not the point - the point is that I can pull up any song I own at any time or any place (home, car, work, vacation, etc…) - which is great when some random thought triggers a memory of a random song you haven’t listened to in forever.  and you’re listening to it seconds later.

may not seem like a big deal to some, but the larger your music collection is, the better this freedom is…..kind of the same freedom you get when you realize your playlists/mixes are no longer limited to the length of a tape or cd.

back on topic though, the battery on my girlfriends mini is a little better than my 30gb, but that’s probably cause mine’s older.  I still love my big old pod better, but I got to admit the click wheel on the mini is awesome…

ok - I’ll shut up now…

Posted by Dennis Lloyd in Irvine, CA on March 3, 2004 at 7:30 PM (CST)

1

I don’t know what it is with the ipod. The ‘World’s Best portable music player’. For one it doesn’t have a radio tuner or voice recorder. The mini is marginally smaller than the usual ipod, slightly cheaper with MUCH less inbuilt memory. Its like a $400 MP3 player: a waste of money.
Get an iriver or DELL instead.

Posted by Dennis Lloyd in Irvine, CA on March 4, 2004 at 12:18 AM (CST)

1

I don’t know what it is with the ipod. The ‘World’s Best portable music player’. For one it doesn’t have a radio tuner or voice recorder. The mini is marginally smaller than the usual ipod, slightly cheaper with MUCH less inbuilt memory. Its like a $400 MP3 player: a waste of money.
Get an iriver or DELL instead.

Posted by Dennis Lloyd in Irvine, CA on March 4, 2004 at 12:18 AM (CST)

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