600e, new battery powers, but "unknown remaining"

[roky]

a few weeks ago, my battery went dead, a 3-month old one -- so i got another -- this one will power the laptop, but i get the flashing yellow light, and when i check battery status, "unknown remaining" -- it doesn't seem to recognize that the battery is there

i'm running off a solar system, in the desert, an crun/charge my laptop through an inverter -- on one occasion, i set the inverter improperly, and may have put in higher than the 16volt required

any ideas? -- thanks, bob