Lindy made a dual battery charge dock that worked like a charm. I used it to recondition even half-dead batteries. The dock always completed a discharge and recharge cycle to avoid the memory effect of NiCd cells. Best results were obtained with batteries precooled down to 8 degrees centigrade before charging.

If you can pick up one for your PB 140-180, it will be a perfect companion to get best mobile use of the computer. If you switch to more recent NiMH cells, you might need some other kind of charge controller.