In article MKNlk.160677$gc5.91017@pd7urf2no,
Tony Hwang wrote:

I'd go for DECT 6 phones with lithium ion batteries.

Some time ago I purchased a 4-handset, Panasonic DECT 6.0 (1.6 gHz)
system. They are equipped with NiMH (Nickle Metal Hydride) cells.

Two days ago I went shopping again for a cordless phone for a friend. I
learned that virtually all DECT 6.0 models are NiMH-equipped. I believe
5.8 gHz systems are, too.

Ni-Cad batteries have been known for memory effect for sure.

Agreed, and there are probably a dozen, different recommendations for
their "care and feeding" - none of which seems to provide long life.
--

JR