HP-34C external battery charging

[rprosperi]

(12-07-2017 06:55 PM)Craig Bladow Wrote:  In older discussions there were concerns with using AA rechargeable that are physically longer and compress the battery contacts more, potentially fatiguing the metal and resulting in the contact breaking off. One solution was to ‘tap’ the button flatter on the rechargeable battery, does anyone have personal experience with this solution?

I have never done this, so cannot say from personal experience, however I've read many reports that doing so can easily damage the battery interior leading to poor life (best case) to explosion (worst case).

I suggest you instead simply use 'flat-top' NiCd cells, that don't cost much more, for example here. These are the same cells as in the original Spice battery pack (you can charge them externally in the smart charger), and insert them into the orginal Spice battery pack frame (held with scotch tape) and simply use a folded aluminim foil conductor for the far end as Dieter noted. Sounds silly, but works perfectly. This is better than jamming stuff in the battery bay to keep the loose batteries tight.