On Wednesday, June 8, 2011 3:59:23 PM UTC-7, Jon Elson wrote:

[PC clock batteries]

It won't make any difference to have the system plugged in, there is no
battery charging circuit on most of these systems.

It isn't about battery charging; when the gizmo is plugged in, there's
a STANDBY power source (always-on) that might (or might not)
take the load off the battery.

Laptops frequently have rechargeable CMOS batteries, perhaps just
because it's hard to open 'em for replacement.

On Jun 10, 3:25*am, whit3rd wrote:
On Wednesday, June 8, 2011 3:59:23 PM UTC-7, Jon Elson wrote:
...
Laptops frequently have rechargeable CMOS batteries, perhaps just
because it's hard to open 'em for replacement.

Mine have non-rechargeables with spot-welded tabs for the connector,
making replacement twice as hard.

jsw