Breaktime1

Hi. I've not had any trouble with the batteries (EB14B - 2.0 Ah) of my other Hitachi product, a 14.4v impact driver. Just the batteries (EB1814SL) for my Hitachi 18v drill. When just freshly charged they work okay. The problem is they don't hold the charge for very long between the last charge and first use. In other words, I have to keep them sitting in the charger at all times except just until the moment when I need to use them. Then I must promptly put them back in the charger. My 14.4v Hitachi on the other hand gives me no such problem. I can leave the batteries out of the charger for quite some time during periods when the tool is not in use, and still count on much of the charge remaining at the time of my last use still there. Anybody else experience this? How to remedy the problem? BTW, all batteries referred to above are the older Ni-CAD type. PS: If I decide to buy a new set of 18v battery packs (or rebuild the existing battery packs with new cells), what are the obstacles to converting to lithium ion batteries. Or can this be done as long as I'm careful to incorporate a special lithium battery protection circuit/board? Thanks, Breaktime1