The Kindle Fire HD uses a 4,400mAh battery. It's non-removable and charges using a microUSB cable. Amazon only includes the cable with the tablet itself, though, so you'll ideally want to get hold of a proper USB power adapter.
Our initial assumption was that the extra weight of the Kindle Fire HD, over its 7-inch peers, may have been down to a larger-size battery. However, its capacity is only a teeny bit bigger than the Google Nexus 7's 4,326mAh unit.
Amazon says that it'll last for up to 11 hours off a charge, and our testing was generally consistent will this level of performance. It'll play video for just under 10 hours at medium brightness, a figure that should raise to the quoted one if you indulge in lighter tasks or take the brightness down a bit.
One of the most notable design decisions in the Kindle Fire HD was to include dual-driver stereo speakers that fire out of each side of the tablet. They provide the tablet with much higher maximum volume that most tablets, including "full-size" 10-inch ones.
However, they're less remarkable tonally. They sound a bit harsh at top volume, although not outright distorted like some tablets, and they're less smooth-sounding than the iPad's internal speaker.
The Kindle Fire HD certainly outperforms the Google Nexus 7, though, and we found it functions pretty well as a casual kitchen internet radio, able to cope with the additional noise of extractor fans and clattering pans.
As with movie-watching, Amazon really wants you to embrace its own music services when you use the Kindle Fire HD. However, it's much better about displaying your own songs here. The music player is split into two sections, "Device" and "Cloud".
The Device tab shows the files that are stored on the internal memory, and Cloud displays any music you've bought from the Amazon MP3 store or have sync'd over the Amazon Cloud Player service. With this, you can sync up an Amazon cloud store with your own music collection, giving you access to your library without having to fill up the Kindle Fire HD's internal memory. You can also download any purchased tracks directly to the tablet.
You can match-up 250 of your own songs for free, or pay £21.99 a year to import up to 250,000. Items bought from Amazon MP3 do not count as part of your allowance, either. Songs are streamed at 256kbps, which may well be higher-quality than some of your own files.
If you want to stick rigidly to your own tunes rather than streamed ones, the Kindle Fire HD offers fairly good codec support. It'll handle AAC, MP3 and OGG. Contrary to Amazon's own specs for the device, the Kindle Fire HD has no problem with FLAC files either, which won't play on an iPad mini.
As a Kindle product, we can't forget the Kindle Fire HD's ereading skills. The quickest summary we can offer is - if you only want to read books, get an Amazon Kindle Paperwhite.
That ereader has a front-lit screen while this tablet has a backlit screen, which is much less relaxing on the eyes. However, if you're after a multi-function tablet, the ereader experience is acceptable.
The Kindle Fire HD uses the same Kindle library as the E-ink kindles, and you can buy a book on a computer and send it to the tablet using Amazon's Whispernet system.
Text looks pretty sharp on the Kindle Fire HD's screen, although the stark black-on-white of the ereader app's page shows off that whites are just slightly off-white on the IPS screen.
Amazon has just launched its lending library service in the UK, which lets Amazon Prime users borrow one book a month. There are over 200,000 books in the lending library, and a Prime membership costs £49 a year. Other benefits to Prime include free one-day delivery and discounts for other, time-specific delivery options.
The arrival of the Lending Library is an important step for Kindle as Amazon's ereaders do not support the EPUB format, used by public libraries to lend ebooks.
Like the Google Nexus 7, the Amazon Kindle Fire HD has just the one camera, a user-facing 1.3-megapixel sensor. This is included primary to enable Skype video calling.
A Skype app doesn't come pre-installed but it shows up within the "Cloud" part of the apps section - it's just a tap away. Sadly, the face-distorting Fatbooth app is not available on the Amazon Appstore yet, but it must only be a matter of time.
There's little doubting that the Amazon Kindle Fire HD offers excellent value. It's a solid upgrade to the original Kindle Fire, with a superior screen and faster processor.
Until very recently, it offered more storage per pound than the Google Nexus 7 too, although with a £199.99 32GB version of that tablet on the way, they're now level-pegging. And for techies the Google Nexus 7 is arguably a better deal as it brings GPS, NFC, a better app selection and a more portable frame.
The Amazon Kindle Fire HD isn't for everyone. Although based on Android, it trades-in many of the system's charms in favour of an interface geared towards getting you to use Amazon services such as Amazon Cloud Player, LoveFilm and the Kindle bookstore. As a result, some tablet basics suffer, and some non-techy types may get confused by the idiosyncrasies of the interface and the divide between local and Cloud content. For those already signed-up to LoveFilm and Amazon Cloud Player, though, it's great.