For anyone looking for a good independent review of the product and performance this is a good place to start.

Rob

Having spent some time away from the office and having had the opportunity to speak to a few customers, we have found that depending on how the HyperMac battery is used it is possible to eke out some extra time of useful power.

Essentially the best results are to be had by, fairly obviously, starting with a fully charged MacBook and HyperMac battery. Then whenever running on battery power, always have the HyperMac battery connected to the MacBook. This way the load is spread between both the internal MacBook battery and the HyperMac, gently discharging both.

The alternative of running the MacBook until the internal battery is flat and then connecting the HyperMac has its plusses and minuses. What seems to happen is that fairly rapidly the HyperMac battery charges up the MacBook battery to a point where the available power is shared between the two batteries according to their relative size. A bit like sharing a pint between two glasses.

However, whilst the Macbook will now run on its own internal power for a while, which could be useful in many situations, in discharging the HyperMac and charging the internal battery, both get noticeably warm. Whilst this warming up is perfectly normal and is exactly the same as charging from mains power, it does mean that energy is being wasted as heat. The energy lost as heat is no longer available to power the MacBook and so there is less usable power from the combined batteries.

I have not tried to make any measurements of the difference, except to say that subjectively there seems to be noticeably longer useful life by making sure that the HyperMac and MacBook are working together from the start. Maybe as much as 10% but different usage conditions make it hard to say - but certainly enough for me to want to post the findings here.

We saw this post on MacRumors Forum:-

Flying with HyperMac battery?

Around reply #9 & #10 there is talk about some good results with WaterField designs Gear Pouches

SFBags WaterField Designs Gear Pouch

We are looking to see if we can get either these pouches or something similar in the UK. hope to have something appearing on the site soon

At first glance, the “Wireless Productivity” test may look a little artificial, however, these conditions are probably similar to what can be expected working on documents whilst on an aircraft with the cabin lights dimmed.

So the Blue figures represent probably about the maximum amount of time that can be eked out from a fully charged HyperMac Battery plus the MacBook internal battery.

If you are planning on having the screen set a little brighter and maybe running the processor or graphics card a bit harder, editing some pictures or watching a movie, then this is more power hungry and the time available will go down. This is where the Red numbers are useful.

For each model the, Red numbers show how many times the internal MacBook battery capacity the HyperMac provides. For example a MBP-150 battery provides 2.2 times the capacity of a MacBook Pro 17″ - So if the 17″ MacBook Pro runs 3 hours of any particular kind of use, the MBP-150 will provide another 2.2 times this, an additional 6.6 hours or nearly 10 hours in total.

So if you know how long your MacBook internal battery lasts with the applications you intend to use whilst away from the power sockets, multiply that time by what the HyperMac provides and add to the internal battery time to get the total.

Hope the above Helps.