Pros: A reasonably-sized add-on that permits full iPod functionality for 49-55 hours after its internal battery has died, compatible with 3G, 4G and mini iPods. Easy to travel with, and use with or without belt clip.

Cons: Less power capacity than previous 3G and mini-compatible version, which sells for same price.
If iLounge gave out awards for iPod accessories that outperformed their advertised specifications, the list would be short, and would prominently include one company: Battery Technology Incorporated. Our earlier review of that company’s first iPod product, The iPod Battery, began by explaining that we were astonished that BTI promised to add 40 hours of extra iPod battery life and instead delivered almost 73. Today, BTI has decided to market The iPod Battery as a 70-plus hour battery solution, and has returned with a largely impressive follow-up product – The iPod Battery ii (lower case intentional).
If you want to understand the specifics behind The iPod Battery ii, see our review of its predecessor; generally, it suffices to describe the new version as an iPod accessory that extends the iPod’s playback time by four to six times the life of its internal battery. White in color and made from plastic, BTI’s Lithium-Ion battery is rechargeable, features its own remaining power indicator with four yellow circular lights, and attaches to the iPod’s Dock Connector port with a short official Apple connector cable. It features a simple on-off power switch, a button to turn the power indicator on, and a collection of three variously sized iPod mounting brackets.
A few features have changed for the better, as well. Full recharge of The iPod Battery ii is achieved in 90 minutes using an included white AC power adapter, and The iPod Battery ii not only permits extended playback when it’s directly connected to any iPod, but will also charge the internal batteries of 4G and mini iPods (not 3G versions). Savvy users figured out how to achieve 3G charging from the prior Battery, but it continues not to be an officially supported feature for the older hardware.
Design
The first differences between The iPod Battery and The iPod Battery ii are initially visual. BTI’s iPod Battery ii is smaller and more rounded than before, looking less like a strapped-on PC battery rucksack than a slightly-larger-than-iPod backpack. Measuring 4 1/8” by 2.75” by slightly under .75” at minimum, The iPod Battery ii starts out smaller overall than its predecessor (5” by 2.6” by 0.8”), and bulks up a half inch in depth if you use the fully detachable belt clip – the prior unit’s large belt clip was permanently attached. This new version therefore lays flat on a table or attaches to a waist better than before, in either case feeling lighter and less bulky. For the same reason, it’s even easier to toss into a briefcase or bag than The iPod Battery, as it consumes less space.
Additionally, The iPod Battery ii uses a new set of plastic mounting clips that are compatible with 3G, 4G and mini iPods, Three clips are provided – one for any 10/15/20GB iPod, one for any 30/40GB iPod, and one for any current iPod mini. Like Apple’s iPod mini Arm Band, each clip includes a small integrated rubber spacer that reduces the possibility of iPod slippage. We tried all three clips, liked their fit, and generally preferred their mounting mechanism to the one used in the prior iPod Battery; though the new clips aren’t super stylish, they were all entirely acceptable for their intended purpose. As a bonus, BTI notes as a selling point that any of the iPod clips can be attached to the battery’s detachable belt clip, giving users an instant iPod belt clipping option. That’s not something we’d use, but it was a nice design thought, and might be useful for someone.
Performance
Aesthetics only tell the first half of the story: as it turns out, The iPod Battery ii is different on the inside, as well. In order to achieve the size and bulk reduction, BTI switched from the first Battery’s 2800mAh Lithium-Ion battery down to a smaller 1600mAh version, which according to company representatives reduces the iPod’s projected runtime from the previous product’s 70 hours down to 40 hours per charge – a projected 43% reduction in play time. But as with the first iPod Battery, BTI’s numbers again turned out to be on the low side.
We tested The iPod Battery ii with the same 3G iPod we used when testing its predecessor, and found that the sequel played for around 32 hours before the four-light meter fell to the two-light mark, then like its predecessor lost its second two lights faster than its first two, becoming unusable after 49 hours, 20 minutes. For those keeping count, 49 hours of playback is over six times what the 3G iPod’s internal battery can deliver, and 9 hours more than BTI promises – actually only a 33% reduction in play time. That The iPod Battery ii outperformed its rated specification isn’t a shock given BTI’s history of pleasant performance surprises, but we were a bit surprised that it ran for almost a full internal iPod battery’s worth of extra time than we would have expected given the difference in BTI’s old and new battery components.
Then, we tested The iPod Battery ii with a fully discharged 4G iPod to see whether there would be any difference – and there was. As with the 3G iPod, The iPod Battery ii ran the 4G iPod for around 48 hours before it became unusable. But unlike the 3G iPod, which it could not recharge, the Battery ii gave our iPod a substantial recharge as well – enough that the combined iPod and Battery ii package played for 55 hours, 37 minutes before falling silent. This was close to five times the duration of what the 4G iPod’s internal battery could muster alone.
Comparisons
There are two key things to note about these results – one for 3G and mini users, one for 4G users. First, The iPod Battery ii delivers more power for 3G and mini iPods than any other product save its predecessor. True, the reduction in The iPod Battery ii’s playback time from 73 to 49 hours may put some prospective 3G and iPod mini users off, especially since BTI’s keeping the price of The iPod Battery ii at the same level as the higher-capacity iPod Battery. The iPod Battery ii will initially retail direct from The Apple Store for $99.95 and likely fall closer to $89.95 through other retailers.
And there’s a tinge of irony in this pricing decision. From a marketing standpoint, The iPod Battery ii delivers as much as its predecessor initially promised, is thinner and sleeker, and works with a greater variety of iPods. But from a practical standpoint, the original iPod Battery may be larger but delivers more juice to 3G iPods and iPod minis – over 40% more than was originally advertised, and about 33% more than its successor. As with the iPod versus iPod mini debate, you’ll need to decide for yourself whether the smaller, sleeker form factor and ancillary features are enough to compensate for the newer product’s lower capacity and similar pricing. But there’s no doubt that the original iPod Battery delivers longer playback time for compatible iPods at the exact same price, only in a larger body.
But secondly, for 4G iPod owners, and even regardless of its lower rated power capacity vis-a-vis the original iPod Battery, The iPod Battery ii is without a doubt the best 4G-compatible battery solution around. It comes close (76%) to the level achieved by its larger, 3G- and mini-only older brother, and takes advantage of the 4G and mini’s recharging capability to deliver superior play time to what a 3G iPod user could expect.
Conclusions
In sum, The iPod Battery ii is the best 4G iPod-compatible battery accessory on the market, and receives our unqualified recommendation for use with Apple and HP’s most current hardware. It’s almost impossible to knock a product that offers two or more full days of spare iPod juice in a slender, well-made package. Only one product – BTI’s previous iPod Battery – offers a better playback time to price ratio for users of older 3G iPods and iPod minis, but then, it feels and looks noticeably bulkier. Unless you really have a need for a third full day of continuous iPod playback before a recharge, we think that The iPod Battery ii is as good a solution overall as you’ll get for the dollar.
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.
Our Rating
Company and Price
Company: Battery Technology Incorporated
Website: www.BatteryTech.com
Model: The iPod Battery ii
Price: $99.95
Compatible: iPod 3G, 4G, iPod mini, iPod photo