HP41 rechargeable battery packs issue

[Sadsilence]

Depends on what is "for a while in a box". Normally NiCD or NiMH batteries can be used for 10 years or longer, when they are really used and charged regularily. Unfortunately due to self discharge "feature" they get totally empty within about a year. And a deeply discharged battery is a gone battery. So I guess you have to rebuild your battery packs again. There are 1/3 aaa nimh cells around with a capacity C of about 150 mAh. Fits perfectly to charging current of 15mA. With C/10 for about 15h NiMH/NiCD cells are charged the best way and even 24h or 48h do not harm.