Powering to the top

Exide batteries have been put through their paces in extreme conditions, powering experiments during the ‘Extreme Everest’ expedition to the summit of Everest to research the effects of low oxygen on the body.

Exide Technologies, whose European and Asian headquarters is in Bolton, provided the batteries to power the research apparatus and associated equipment used in the four laboratories – the highest of which was at 7,900m asl (above sea level).

The batteries were the same Dryfit Gel batteries that are fitted in boats, caravans, wheelchairs and golf caddies. During the expedition they could be used where people were eating or sleeping because of their extremely low emissions and the fact that no acid vapours are released, unlike conventional lead acid batteries. The electrolyte in these batteries is trapped in gel, so even when one of the battery casings was damaged because of an accidental impact, it was still serviceable.

The batteries were used in extreme conditions, down to –10oC, and were pushed to their limits and discharged to depths greater than ordinarily recommended. This was because the batteries were used in conjunction with a generator and the team wanted to minimise the generator usage and to ensure a smooth and continual supply of power to the sensitive medical equipment. If there had been any disruption to the blood gas analyser for example, the whole experiment would have to be restarted.

After the expedition returned to the UK, Mike Carrington, senior applications engineer at Exide Technologies, carried out tests on the batteries.

‘Initial tests showed that the batteries had been left fully discharged after the expedition, for a long period, which is not recommended.’ he said. ‘However, we found that they retained 80 per cent of their capacity upon first charge and they increased capacity with further charge discharge cycles.’