So actual future is significantly a function of us the consumers, by making Anker act by buying or not buying from Anker, a competitor pulling sales from Anker would be far more powerful than a community forum opinion. Market forces!
To look at the thermal and power conversion efficiency watch these two videos and focus on the size of the battery, the shape of the battery and the costs.
The batteries are very thin and flat, these are 15Wh for the NExus 7 and 34Wh for the Nexus 10 and these devices both have 9 hours battery life. The Nexus 7 is 290g and 0.2L volume, the Nexus 10 is 603g and 0.42L volume.
These devices are old and so slow for multitasking but they allow me to do is store powered off 60% charged my 19 month old $650 Google Pixel C to make it last longer (less exposed to accidents and the battery ages slower if not used at part-discharged) so if I spent $40 and made a $650 device last say a year longer works out net better value.
Observe you could not carry really these batteries around as shown, Anker could not for example make an external battery like these as the Lithium is very exposed, it is soft to touch and easily bent and therefore would be unsafe. If you placed these shaped batteries in cases which adequately protected them due to the thinness which allows a lot of torsion you’d need a thick casing, and end up with a battery not far in size and weight the tablets these batteries are inside. So to minimize packaging weight you end up with a less-flat closer to a cylinder shape, often via a set of 18650 batteries like this
Take the 20000mAh Powercore as an example it is 74Wh and you lose energy in conversion so is say 1.7x recharges of the Nexus 10, so equivalent of 16 hours of us, and you’d pay $40 typically for 20Ah, and is 356g and 0.22L. Or consider it $2.5 / hour.
A similar calculation at the lower end is say a Powercore 10000, often around $20 for the Nexus 7 gets you to $1.8 / hr.
That is logical, it becomes more expensive to make a larger device last longer.
I would argue that makes a lot of sense in these tablet’s situation on a weight, volume and cost basis. This is why I suspect the 20Ah batteries for tablets has been selling really well for Anker, they make a sensible balanced option for long times off-grid.
Where it begins to break down is as you scale up the problem, let’s take a higher end modern laptop like say one of the new Chromebooks like the Asus C302CA which has a 39Wh battery and has a 10 hour battery life. Take the current highest Anker battery you can buy - the 26800 PD costing (if you could buy it by itself) about $75 and would give 20 hours of laptop use. Or consider it $3.75 / hr.
So then a smaller 7" device, to extend its life is $1.8/hr, a 10" is $2.5/hr and a 13" is $3.75/hr. i.e. it becomes progressively worse value.
What I am observing now attempting to keep a large device going longer is not actually happening in the market, what I’m seeing is folks carry a 2nd smaller device, they then drain its battery for uses which fit a smaller device and then combine the total battery life of 2 devices rather than carry a larger battery for the larger device. It works out overall more useful and flexible and gives you a spare device in event of damages.
The Amazon Fire HD 8" for $54.
So overall, the highest end of the external battery pack idea is being squeezed from below via:
- the battery life of the larger devices is actually often enough, in the 7-10 hours range which is a full day for most people
- for the longer trips you’re beginning to see folks carry a smaller device with its own 7-10 hours
- those smaller devices can themselves have their battery extended far cheaper via smaller batteries.
Where I see the biggest market gap at the higher end is in solving the recharging problem, so say you had a larger computer (laptop) a small tablet, a phone and say a smaller battery, and a earbud , that is 4 or 5 devices and the future is USB-PD with a couple of years overlap with MicroB. So a 4 port with 2 USB-C PD and 2 USB Type A, or a 5 port with 2 or 3 USB-PD and the others USB Type A.