Lithium battery powered gadgets.

Hi,

Here there's a XO Tablet and a PlanOn Printstik.  Both unused for at
least 5 years.  The original chargers are available.

When the tablet is connected to power, no light comes on and there's
no response to the power button.

When the printer is connected to power and the power button is
pressed, the green indicator light switches on.  Pressing the paper
feed button switches the power light to red.

Can these gadgets be resurrected?  Leave on the charger for a day?
Replacing liithium cells is probably not feasible.

Ideas?

Thx,                             ... P.