I've found some lithium cells that will fit the battery frame, and pretty close to the same capacity (3800mah, stock is 4000mah)... I'll be replacing them in my Canvas as soon as they turn up from China. If all goes well, I should be able to do the same for other people's batteries if desired... would be a lot cheaper than what Vaio wants to do for us Will see how some new cells do anyways. If there's interest I'll get a few extra cell sets. Regarding heat being the issue... what annoys lithium packs is over charging, discharging, and for some, long term storage at 100% (it's what that battery saver option was made for, to keep the pack at a long-term-happiness voltage).