Smartphone. Tablet. Laptop. Maybe an e-reader, gaming device, and camera chucked in there too. Chances are, a lot of you carting around a lot of electronics on a daily basis, and most of it has a battery. Here's how to make the perfect gadget bag, one that not only carries your crap, but keeps it perpetually perked up too.
A bag: Obviously. I've trialled this with a Timbuk2 messenger bag (amazingly good satchel-style bags for carrying tonnes of stuff around, if you're looking for one), and a Victorinox backpack that has an equally loyal following. To be honest, though, this will work with any decently-sized bag that has at least a few pockets to stash stuff in.
A battery: At the heart of the charging system is a decent-capacity battery which, crucially, supports pass-through charging. That means that the battery can take power going in from the wall, and pass it straight on without making it first go through the battery. For my purposes, I used the a 12000mAh Anker portable battery, which is famously cheap and reliable, if not the prettiest thing to look at.
It's good for charging both tablets and smartphones -- about one or two extra charges in the case of the former, and normally around five or six for the latter.
The battery means that with just one wall charger, you can juice up two devices whether you're using mains power, or on the go, without having to carry extra plugs or cables or move anything around. That's the secret to this bag.
Cables: The exact make-up of the cables depends on what gadgets you're planning on charging, obviously, but whatever you're using, make sure that the cables you get are for exclusive use on this project -- you don't want to be ripping them out of the bag all the time.
Wall charger: In the interests of slim design, I'd recommend this wall charger: not only does it fold down pretty small, but it also has non-movable live pins, which should help the longevity in the bag. This is the charger that'll be permanently attached to your battery block.
Duct tape/sewing kit: because you'll need something to patch up the holes you'll be cutting in your bag.
Now, rather than just bunging everything in a front pocket, we're going to integrate all the bits and bobs of our charging system as far as possible.
First up, you need to decide where you're going to put that battery. Normally, some kind of smallish front pouch where it won't slide around too much is the best.
Then, think about where you're going to want to store your different gadgets when they're charging. This is important because of the next step -- cable routing. Look at the design of your bag, where the power source is, and where your gadgets are going to live. Look at how the lining is constructed, where you're going to be able to cut without stitching, and so on.
Once you've worked out exactly where you're going to feed the cable through, it's time to start cutting. You only need a small hole, enough to get the smaller end of a Micro USB cable through. The neatest way to cut is to pinch a tiny bit of fabric where you want to cut, and use a pair of scissors to make a tiny incision about half a centremetre apart, then cut the leftover fabric out.
To stop the hole from fraying and generally looking a bit terrible, you've got two choices: sewing, for the more elegant, and duct tape, for the lazier among us. If you're sewing, you'll want to be using a whip stitch to go around the edges of the hole, stopping the fraying,
If you're using duct tape, get two bits of duct tape, both about twice the size of the hole. Cut a tiny hole in the centre of both pieces, and feed them onto the cable, with the stick sides facing each other. Push the cable and one piece of tape through the hole, then stick the two pieces of tape together. The end result should be that the hole in the fabric is now covered on both sides by duct tape that's sticking to itself, and fraying is prevented.
Once you've got the holes all sealed up and the cable threaded, you're pretty much done. You should have a battery tucked away, hopefully with the charging cable attached and easy to get to, so that juicing up your assortment of gadgets at the end of the day is just a matter of sticking the plug into the wall, switching the battery on, and putting your feet up.
Let's face it -- you're going to struggle with most smartphones' battery lives, but one thing you shouldn't have to struggle with is using them as your day-to-day camera. The Nokia 1020's 41MP PureView camera can leave more room in your bag for charging cables as you can certainly leave your DSLR at home, as O2 Guru TV shows in their video below.