The memory effect is only really applicable to NiCads. NiMH and Lithiums do
>not have this phenomena.
>
>It could also be the gas guage inside the shaver. Some gas guages need the
>battery to be completely discharged so they can get a low reference point.
>Frequent short charge discharge cycles allow the errors to build up. A good
>discharge resets everything.
>
>Bill Naylor
>Electronworks.co.uk - electronic kits for education and fun
>
Just don't try full discharge with most lithium batteries, they tend to get incendiary if you do.