On Tue, 17 Nov 2020 12:14:32 -0800 (PST), Lobster
wrote:

snip

Part 2 of the question is that the original power packs are NiCd. The OEM charger (a DC1804T) states that it's good for both NiMH and NiCd: so does that mean I can buy NiMH cells and simply swap those out for the existing duff NiCd items?

If that is the case then potentially 'yes'.

Or will there be electronickery inside the power packs that I would need to contend with, and should therefore stick with NiCd?

Not that should care AFAIK as with NiCd / NiMh most of the
'intelligence is in the charger. I don't think they have any voltage
protection / cutoff in the battery as shown by the fact they (or all
the ones I have ever played with) do get slower and slower, rather
than just cut off, as per most lithium powered things.

You are probably looking for 'tagged' sub C cells but it's best to
check what's in there first.

Cheers, T i m