Possible to calibrate battery?

[AZImmortal]

I haven't used my e260 in about a year and earlier today I decided to start using it again. I charged it for most of the morning but I can't seem to get Rockbox to report anything higher than a 94% charge even after I leave it charging for a while. I'm currently running the battery bench plugin to see what kind of shape the battery is in. In the meantime, is there some way to calibrate how Rockbox reads the battery's capacity?