This is a problem found in the battery information dialog (press Ctrl+Shift+P in the system screen). The backup battery bar appears to be only around 3/4 charged at a level of 3.0V or similar. It therefore appears that the battery is not fully charged. This occurs even when a brand new battery is put in the machine.

There is no need to worry about this. This is because the maximum output of the battery is 3.0V, but the guage goes upto a maximum of around 4.0V. There is no way to correct this.

If you take the battery out you can confirm this. Written on the upper side of the battery is its make CR2032 and beneath this '3 Volts Lithium Cell'. This confirms that the maximum voltage is 3.0V as reported by the battery information dialog.

Irrelavent Note: It is likely that your backup battery will stay at 3.0V for a long time. I have my Psion 7 about 8 moths and is has gone down at all despite heavy use.