Before you wonder, no I don't smoke or vape... my local vape shop in Kingston-Upon-Thames carries a surprising array of cool gadgetry like proper PC keyboards and the like, along with questionable power packs...

They may have been cutely coloured and sport perfect dimensions to fit in the float but it's time to confine these power packs to the toolbox for quick lab tests. Not worthy of the Mercator, they can't hold their own against a measly 400mA discharge for very long at all.

Time to bring in the Daddy - Suunto makes some of the finest dive computers in the world (along with Shearwater and other companies) and unsurprisingly their power pack rocks, sporting not one but two USB sockets so we can accommodate a separate connection to the iPhone for 4G connectivity.