Review: BTI The iPod Battery

Pros: Outstanding extended battery life for the iPod, surpassing BTI’s conservative estimates, requires no additional costs for upkeep.

Cons: Larger than Belkin’s cheaper but less powerful solution, face plate clips could use a redesign, belt clip adds a bit of unnecessary bulk, battery indicators inaccurate.

When was the last time this happened to you: an advertised product promised five times better performance than something you already own, but it turned out to be ten times better. This doesn’t happen, right?

Thanks to Battery Technology Incorporated (BTI), it happened to us, and it can happen to you, too. The iPod Battery is a rechargeable external battery advertised to keep an iPod or iPod mini running for “up to 40 hours of music play per charge,” but as we’ve discovered, there’s a significant likelihood that your iPod will get closer to twice BTI’s estimates.

If iLounge wanted to come across as flippant, we would end the review right here by stamping our “Excited” rating all over BTI’s first iPod accessory. But that would ignore two other important points we’d like to discuss: first, the design of The iPod Battery, and second, the specifics of our battery test, which yielded approximately 73 hours of continuous iPod play time.


Like Belkin’s Backup Battery Pack for the iPod ($69.99, available for $40 and up), BTI’s concept for The iPod Battery is simple: by attaching a larger second battery onto the back of an iPod and connecting the accessory through an included Dock Connector cable, you enable the iPod to run for a longer period of time than Apple’s stated eight-hour internal battery expectancy. The competing products even look similar to one another, each with glossy white plastic parts, an on-off switch, and four indicator lights to show remaining battery strength. Importantly, neither product recharges the iPod’s internal battery; both keep the iPod running only for so long as they’re connected.

Review: BTI The iPod Battery

BTI’s design differs from Belkin’s in several key ways. First, BTI uses a high-capacity rechargeable Lithium-Ion battery instead of Belkin’s four disposable AA batteries, which theoretically gives each side an advantage: BTI’s battery lasts longer and can recharged “over than 350 times,” according to the company, but Belkin’s AA batteries can be replenished without a charger just by stopping at any store. However, as we’ll explain in the Performance section below, this turns out to be a practical advantage for BTI except under the most unusual circumstances.

A second difference: The iPod Battery is larger, consisting of a battery enclosure (5″x2.6″x0.8”), an integrated belt clip, and three detachable, interchangeable plastic face plates. One face plate fits third-generation 10/15/20GB (thinner) iPods, another fits 30/40GB (thicker) iPods, and the third fits any iPod mini. Face plates attach to The iPod Battery with four locking plastic clips, and can be removed entirely to keep the iPod and its peripheral separate.

While BTI’s face plates aren’t substitutes for standalone iPod cases, they hold iPods firmly to the Battery and look good doing it. Each plate provides full top, button, Wheel and screen access, plus enough bottom access to connect the short (2.5”) Dock Connector cable to each iPod’s underside. The top hole is used to slide the iPod in with its back towards the battery enclosure, which includes two foam rubber pads to prevent the iPod from being scratched as it’s mounted.

Together, the iPod and iPod Battery look a bit nicer than Belkin’s suction cup-based iPod backpack, though bulkier. When assembled, BTI’s battery case (0.8”), belt clip (0.38”) and attached face plate (0.65”-0.88”) bring the total thickness of The iPod Battery to around two total inches. The added bulk is not enough to make a practical difference for most users, but it’s larger nonetheless.

Review: BTI The iPod Battery

As a final note or two on design, each iPod Battery includes a detachable cabled power cube to permit recharging, and a standard DC power-in port sits at the top of the Battery. Next to the DC port is a push button that lights up the Battery’s four power percentage indicators, which are labeled 25, 50, 75 and 100.

The left side of the battery includes a Charge light that turns on during recharging, and an On-Off switch that controls access to the Battery’s juice. Flip it off and the iPod must rely upon its own power; flip it on and the iPod’s own battery indicator fills entirely, running down the external battery until depleted, and only then switching to its internal reserve.

Our only quibbles with BTI’s design are minor ones. First, the detachable face plates are a great idea, but the clip system could use a little work. Even when following the instructions, it’s challenging to get the plates on and off, and since we’ve seen the top two clips flex a bit during normal use, we’re pretty sure that repeated changing of the face plates will lead one of these clips to break off. Users should plan to keep a given plate attached or avoid repeated detaching if possible.

Second, though we think the quality of the belt clip is beyond reproach, we’re not sure what percentage of buyers will actually want to attach The iPod Battery to their belts. We think that even Batman would find the laptop battery and iPod combination to be too big to walk around with, but even if we’re wrong, an ideal implementation of The iPod Battery would still permit the clip to be detached to reduce overall thickness.

Third, like Belkin’s Backup Battery Pack, the battery life indicators aren’t perfect: the battery stayed on 75% power far longer than 50%, and remained on 25% at a point when it was apparently not capable of powering on the iPod. We also found the “still charging” indicator to be a little flakey, but not terrible.

Finally, as we’ll explain below, we hope that BTI will consider offering a pass-through or splitter Dock Connector as either a pack-in or complementary accessory for The iPod Battery in the near future. Combined with slightly revised face plates and a detachable belt clip, such an addition to The iPod Battery would virtually guarantee that a future accessory surpasses even our Excited rating.


Based on our past experiences with overaggressive product marketing, we were skeptical when we saw an advertised 40-hour run time on the packaging for The iPod Battery. Last year, iLounge’s review of the Backup Battery Pack explained that “Belkin claims 15-20 hours of music play with fresh batteries—but note: that number assumes a fully charged internal iPod battery, too. Once our iPod’s internal battery was drained, we only got about half of Belkin’s claimed play time on a set of fresh AAs.”

Therefore, we began our tests skeptically, beginning by draining our iPod’s internal battery to zero. Forty hours of advertised run time wouldn’t mean much if we had to use the iPod to achieve them, so we wanted to see just how long The iPod Battery would run on its own. We set the iPod on 50% volume with a 1,500 song playlist (featuring tracks at various compression rates and sizes), checked the battery indicator lights (100%), wrote down the time, and walked away.

Twenty-five hours later, we came back and looked at the iPod, and found that it was still playing. That BTI’s Battery hadn’t died after 20 hours suggested that, unlike Belkin’s advertised Backup Battery Pack estimates, our performance wasn’t going to be cut in half if our iPod was out of juice. Then we pressed the battery indicator button, and saw something unusual: it said that 75% power still remained.

Review: BTI The iPod Battery

That was hard enough to believe, but when we came back twelve hours later (37 hours into our testing), the iPod was still playing – and still showing 75% power. And again, eleven hours after that (48 hours into our tests), the indicator lights came up the same. At the 67th hour of testing, The iPod Battery hit the 50% mark for the first time. The battery hit 25% around the 71st hour of testing, and then died at the 73rd hour.

Needless to say, we were surprised enough by the battery’s longevity that we wanted to confirm our results, and took the unusual step of contacting BTI to ask about their internal testing procedures for The iPod Battery, specifically asking how they’d calculated a 40-hour run time. The response was as follows:

BTI: “We ran numerous tests on the iPod Battery and in some cases, our iPod Battery actually powered the iPod for over 70 hours (straight ‘music play-time’). […] Battery Technology, Inc.  tends to be on the conservative side when listing the run-times of our batteries for marketing purposes. […] We calculated that the average user would be using the iPod Battery for 75% music playing and 25% for downloading, etc. and 40 hours was the minimum total run-time per charge.  Again – this is conservative.”

To slightly rephrase this, BTI estimated that the iPod’s hard drive would be running for 25% of the time it was turned on – a conclusion that overlooks two critical aspects of iPod use. First, during optimal, playlist-based playback – the way Apple measures battery life – the iPod’s hard drive is actually accessed only briefly – for six or seven seconds, maximum, once every four to eight tracks. Even less than optimal playback – say, picking a new track every track or two – will run the hard disk five or ten seconds for every three or six minutes of music playback, nothing close to a 3:1 playtime to disk access ratio. The numbers are closer to 10:1 in favor of playtime.

Second and more importantly, since neither The iPod Battery nor any other Dock Connector-ready iPod accessory includes a pass-through cable, the iPod will almost never be “downloading” continuously while The iPod Battery is plugged in – you can’t plug the iPod into other Dock Connector-based devices at the same time. If BTI’s peripheral had included some sort of pass-through or splitter cable, permitting the iPod to be simultaneously connected to the Battery and battery-draining accessories such as Belkin’s Media Reader and Digital Photo Link, the story would be different, but as-is, the only way to tax the iPod’s hard disk while Battery-powered is during the use of voice recording peripherals, which attach to the iPod’s headphone port.

Review: BTI The iPod Battery

Given that our “optimized battery conditions” test ran for 73 hours, it goes without saying that under real-life conditions, we would expect BTI’s battery to outperform the company’s stated estimates by a fair margin. To run the battery down more quickly than the estimates, we’re guessing that a user would need to keep the iPod’s backlight permanently on and change audio tracks once every 35 seconds, or something equally unusual.


Apple’s competitors have tried to make hay of the iPod’s comparatively unimpressive battery life, but for the average user, that hasn’t mattered: short average commutes and numerous recharging accessories keep most iPods playing long enough before requiring additional power. But users with heavier battery demands now have two solid alternatives.

Given the choice between competing battery solutions from Belkin and BTI, we think the choice is relatively clear. BTI’s entirely self-contained battery runs five or more times longer than Belkin’s, doesn’t require the purchase of extra batteries, and is in the same general portability class despite being somewhat bulkier overall.

That BTI’s solution is initially more expensive may be perceived as somewhat of a disadvantage, but it’s equally true that the cost to keep Belkin’s device actually running – whether it’s with 20-packs of AA batteries ($10-20 each) or two sets of AAs and a recharger – will be comparable, perhaps higher. Additionally, our earlier point about Belkin’s theoretical advantage (being able to fuel the iPod at any time with fresh batteries) is largely mooted given that The iPod Battery runs for so long between recharges.

Our only issues with BTI’s first iPod accessory are truly minor ones, and though we think The iPod Battery would benefit tremendously from the invention of a pass-through or splitter device to simultaneously permit iPod recharging and the use of Dock Connector accessories, we can’t penalize the product for lacking such a feature. It’s a tribute to BTI’s design that we could even conceive of a way to keep the iPod running long enough to make maximum use of disk-draining Dock Connector peripherals. We can only hope that both Apple’s and BTI’s future innovations go even further to reduce battery concerns for iPod users.

Jeremy Horwitz is Senior Editor of iLounge and 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.

Table of Contents

Our Rating

Highly Recommended

Company and Price

Company: Battery Technology Incorporated


Model: The iPod Battery

Price: MSRP $99, Available for $81.00 (shipped) and up

Compatible: iPod 3G, iPod mini

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