The 5 Best iPhone 4 External Battery Devices

iPhones, including the new i4s, are notorious for short battery life. You don't need to be a power user to run your phone down before the end of the day. If you are a power user, you are certainly going to need some kind of back-up to get the most from your phone.

The neatest and most reliable way of extending battery life is to use an external battery.

• These can be small units that push onto the bottom of the iPhone.
• They can be the sort of separate device that will recharge your iPhone battery using a USB cable.
• A solar powered re-charger can be useful
• Phone cases that include an external battery are available.

Each approach has advantages and disadvantages.

• A push-on external battery will mean you don't have a mess of cables to think about but they are low on extra capacity.
• A case with battery included can be very neat and secure- but only if you want to use a case at all.
• The external batteries that use cables are more versatile and will power a lot more devices- like the iPad and iPod. They can be pretty big, though.
• Solar power can be a slow option.

iPhone 4 Battery Cases

Mophie Juice Pack Air Case

This is one of the most popular cases around.

There is a choice of colors- red, white, yellow or black.

It is one of the most snug fitting and stylish battery cases.

It is even certified by Apple as a compatible device- a rare, acknowledgement.

The 'soft touch' finish is appealing in the hand and, of course, there is full access to all ports with no need to remove the case for charging.

It can add around five hours of browsing on 3G networks or nine on Wi-Fi.

Works with AT&T and Verizon phones.

New Trent IMP180 Astro Battery Case for IPHONE 4 and 4G

Some people would say I have saved the best case to last. Certainly the level of appreciation from buyers around the web is very high for the Astro. It has a discrete, ultra slim design and the renowned build quality and reliability of New Trent (who make the most powerful external batteries available, see below).

The inbuilt battery offers 1700 mA and it can be recharged around 500 times before you need think about a replacement.

PowerSkin Mili

Power skin offer a 1600mAh case, which adds only 18mm to the thickness of the phone. It offers an extra 360 hours standby time, 6 hours of 3G call or around 11 hours of WiFi Internet access. It is a neatly designed device and offers good protection.

It is not cheap though, retailing at $85 most places online.

iPhone 4 and i4s Juice Packs

New Trent External Batteries

This is the most popular iPhone 4 juice pack around.

It will not just recharge the battery of an iPhone 4. It will connect just as easily to an iPad, iPod, iPhone 3G 3GS, Motorola Droid , HTC Android Phone or Blackberry. With a $5 adapter it can be used with a PS3. It can also be used with many notebooks.

The battery is charged via an AC wall plug charger or via USB from a PC (or similar).

It connects to Apple devices with a mini USB cable.

The manufacturers point out that it will give you 50 hours of movie time for an iPhone 4. For a power user it will comfortably double the time you can use your iPhone. For many people, it will mean only recharging from a wall socket every 3 or 4 days.

For even more battery capacity you could try the New Trent Extreme. It offers 11000 mA as opposed to 8900 mA of juice.

The disadvantage of this kind of charger is that it can be messy connecting up. The advantage of all the extra power becomes very obvious on long trips!

Satechi iCel 4800 mAh Battery Extender and Charger

This is a neat, soap-bar sized and very tough unit that will charge an iPhone4 plus PDAs, USB camcorders and mp3 players such as Sansa, Zune and Creative Zen.

YooBao 4800mAh External Battery Pack

This is a no name product but it gets great reviews around the net for performance and reliability.

The range of tips is certainly impressive and it will do a lot more than charge an iPhone.

This means you need to make sure you get the right product. There are YooBao battery packs for all kinds of smartphones- from Nokia to LG.

1000mAh Mini

This is the least expensive external battery that will give you a real extension of battery time. Even so, if your iPhone 4 battery is getting old, or is out of condition, don't expect much more than a few hours of extra use.

Apart from the price it has the advantage of being a neat fit and your phone won't look like it has a mechanical parasite attached to it. The connection is also secure so it won't fall off. And no wires!

If you only need a short time boost for an iPhone 4, this has to be worth thinking about.

Solar Power Juice Pack for the iPhone 4

This is less of a solar charger, in truth, than a useful and inexpensive battery case.

In a strong light, the solar cells will replenish the 2400 mAh Smart lion-polymer battery in around 4 or 5 hours, This can be handy if you live in sunny state or like hiking but is slow for for the average user.

Mostly, people will recharge the case in the usual way from a wall outlet with the adapter provided.

The battery pack will recharge an iPhone to more or less full capacity,