At odds with the accepted modern system of using solar panels to generate electricity on polar icecap expeditions, my April 2011 speed expedition will revert to using AA batteries. This is something more commonly seen in the equipment lists of those on the Arctic Ocean early in the season when sunlight is absent.
Why is this? Despite the endless hassle I've experienced with solar arrays and reservoir batteries, I do think solar has a place. At the end of the day, it's all down to weight. If the solar panels and associated cables etc. are lighter than the equivalent number of batteries, it's a good idea. The problem is of course that if the system fails, you have very little in the way of stored power to charge vital items, such as GPS.
I plan to be on the icecap for less than nine days with my team-mate and the weight of a solar panel, intermediate battery and spares would be well over a kilogram. Given that AA Lithium batteries weigh only 17g each and hold 4.3Wh each, for short expeditions they are ideal. They also hold their charge well and you know the energy is there, stored, rather than on the whim of the sun.
We plan to take 42 AA batteries, which weigh only 720g and hold over 180Wh of power.
Even taking into account decreased performance in low temperatures, this will allow us to charge an iPod 18 times, change GPS batteries once, charge a satellite phone twice and charge cameras 8 times. The added advantage is that it cuts out the unreliable intermediate reservoir battery needed for solar recharging and provides a nice, even current without fluctuations.
Photo (clockwise from top left): Iridum 9555 sat phone, Canon G10 battery, Iridium phone battery, home-made 12V AA battery pack and female car charger socket, 8 Lithium AA batteries, Garmin eTrex GPS