University of California battery boffin Kent Griffith has been testing the effects of keeping a laptop fully charged, and apparently, the numbers could be better.

Griffith told Gizmodo that leaving your laptop battery at a full 100 per cent charge for extended periods is like a tech time bomb. If you expect a marathon run from your laptop after such treatment, you'll be lucky to get a sprint.

Griffith prescribes a healthy 20 to 80 per cent charge. His top tip: charge up, unplug, and let your laptop live a little. This 'mid-range' mantra could be the elixir of life for your laptop's lifeline.

This is because the lithium-ion battery is a delicate dance of graphite and lithium cobalt oxide layers, with lithium ions shimmying between them. A battery brimming at 100 per cent is a lithium lion's den, with energy bursting to break free. But cram too many lithium ions into one layer, and you're dialling up the stress levels. The battery's happy place is a balanced 50 per cent.

Griffith criticises high-speed charging cables, accusing them of hustling lithium ions too hastily and harming hardware.

The myth of eternal plug-in power has its roots in the days of desktop dominance, where a constant connection to the mains was the norm. But laptops are a different breed, drawing life from their batteries, not the socket. And yet, we've been hoodwinked into thinking that a laptop latched to the mains is living its best life.

This 'perma-charging' practice is a passport to poor performance. That trusty old laptop’s full charge might not take you as far as you think.

This charging charade continues because it is part habit and part convenience. Most of us are desk-bound, our laptops locked to the power supply like a desktop. But venture away from your voltage haven, and the reality of a weakened battery becomes all too apparent.