Q: What is the best external iPhone or iPod touch external battery? You have so many reviews, but which one is the best?
– Adam
A: There’s no single answer to this as it really depends on what you’re looking for. “Best” is a subjective term and different users will usually be looking for different features in an external battery pack. Every expansion battery pack made for the iPhone or iPod touch is a trade-off between size and capacity with more powerful battery packs being larger than the slimmer, smaller battery packs.
Capacity for rechargeable battery packs is normally measured in milliampere-hours (mAh), and this capacity rating for an external battery should always be at least equal to the internal battery in the device that you’re connecting to, if not slightly above. The iPhone 3GS packs a 1400 mAh battery, while the iPod touch battery is rated at only 900 mAh, since it has lower power requirements in not having to support a cellular radio antenna and GPS receiver.
Therefore, if you’re looking for a battery pack to give you a full recharge of your iPhone, it will need to be rated for at least 1400 mAh—batteries with lower ratings will likely not even engage the actual charging circuit, although they will provide supplemental power as long as they remain connected.
For our purposes we tend to prefer battery packs that provide the most power for the price, but recognize that other users may be looking for battery packs that provide more portability or a slimmer form factor. Generally, if you’re looking for raw power, we consider the best option on the market right now to be the Just Mobile Gum Pro (iLounge rating: A-), a 4400 mAh battery that is actually just a generic USB charging source rather than an iPod or iPhone-specific accessory. With 4400 mAh, however, you can top up your iPhone or iPod touch over the course of a few days of normal use before the pack itself needs to be recharged.
For the iPhone 3G and iPhone 3GS, another one of our favorites is the FastMac TruePower IV (iLounge rating: B+), which is a iPhone-docking battery pack that provides 3300 mAh of capacity while adding a couple of other nice features such as a secondary USB charging port, an LED light for the iPhone camera and an iPhone-style Dock Connector so that you can recharge it in any iPhone or Universal Dock device.
This battery pack will technically also work with the iPod touch, although the slimmer size of the iPod touch makes it an extremely loose fit and therefore impractical for iPod touch users.
If you’re looking for something slimmer and large capacity is not a serious factor, the Mophie Juice Pack (iLounge rating: B) and Incase Power Slider (iLounge rating: B-) are reasonably nice case-integrated batteries, but you’ll pretty much need to charge them each night, as they offer only 1800 mAh and 1330 mAh of power, respectively, making them useful as supplemental batteries that you keep strapped to your device during normal daily use to extend the battery life, rather than as a practical source for topping up your internal battery. It is also worth noting that these are case-based batteries that only work with the iPhone models and are not compatible with the iPod touch due to their physical dimensions.
There are also several batteries that simply dock onto the bottom of the iPhone or iPod touch and are therefore non-device-specific. Examples include the RichardSolo Smart Backup Battery Pack (1200mAh, iLounge rating: B), RichardSolo 1800 Smart Backup Battery with Laser Pointer & LED Flashlight (1800mAh, iLounge rating: B-) and the Griffin PowerBlock, PowerJolt + PowerDue Reserve units (500mAh, iLounge rating: A-).
