wrote:
The ones I've used so far (DirtDevil, DustBuster) all use NiCd, and
they had really poor charge capacity - all would run out of steam in
1-2 minutes, even though I'd make sure to charge them for several
hours, or even days, prior to use.

Sounds like you have a problem with your battery management. See
http://en.wikipedia.org/wiki/Nickel-...#Memory_effect

Una