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Dieter · (This post was last modified: 10-01-2018 05:39 PM by Dieter.)

(10-01-2018 04:41 PM)badaze Wrote: Unfortunately I do not have an external charger. I have the external one for HP 29C and I’m pretty sure HP didn’t made one for Sting calculators.
If there is a way to charge the battery pack externaly I’m interested.

Take a look at this thread on Sting battery packs. It sounds like the original battery pack can be modified to accept four regular AA cells. There also is a link that shows such a modified battery holder. This mod seems to be quite easy to do.

Once you are able to use four individual AA cells the problem is solved: Simply get a set of four decent NiMHs (e.g. Panasonic Eneloop) and a smart charger (e.g. the ubiquitous BC-700 and its siblings). This solution provides about four times (!) the original battery capacity and reasonably fast, safe and convenient charging (due to the "intelligent" charger). Which again makes the batteries last longer.

I assume (!) it may even be possible to use (single-use) Alkaine cells. This way you can preserve the continuous memory contents while the NiMHs are charged, even if you do not have a second set of rechargeable batteries.

Dieter