On Tue, 15 Mar 2016, Paul Koning wrote:
From the various comments, it sounds like NiMH is a
useable substitute.
On the other hand, NiCd batteries are still readily available.
Yes, but NiCd cells really don't like being charged only and never
discharged. And they tend to crystallise quite badly with age and
"misuse"; best examples are 3.6V NiCd battery packs as CMOS battery on
many mainboards.
Christian