As Adam says, Booster charges are fine. A lithium Ion pack should be good for about 3-400 cycles but any change from discharge to charge state counts as a cycle, so while booster charges don't actually shorten the life of the pack they do knock one cycle off the batteries life. So in terms of total runtime from the pack you will get a shorter life with boost charges, but in terms of number of charges you wont.
Another tip is that you should try and avoid leaving the pack in a discharged (i.e below 20% capacity remaining) state for long periods of time. If you are storing a pack for an extended period of time (say it's a spare) it's worth charging it once every 3 months or so.
The reason for this is that Lithium Ion (like many other battery technologies) has a self discharge behaviour. Now this is not a problem if using a single cell. But in a pack of series connected cells (like in your laptop) if one cell dips down to a level below that of the other cells, when you try to use the pack the cell gets reverse charged by the current flow through the series circuit. This is called cell reversal and it's not good for them.
On Friday 01 August 2003 07:29, syd wrote:
I've just bought a T-series Thinkpad. It has Lithium-Ion batteries. AFAIR these do not have the 'memory' effect so does that really mean in practice that it is perfectly OK to give short booster charges no matter what the state of charge/discharge?