The Power Management System - Husky MP2500 Manual

8.2.4.2 If alkaline batteries are fitted
CAUTION: NEVER connect the AC adaptor if alkaline batteries are
installed and charging is enabled. The MP2500 will
attempt to charge the alkaline batteries, which will
make them leak corrosive chemicals which are
hazardous and will damage the MP2500.

8.2.5 The power management system

This section provides background information on the MP2500 power
management system.
8.2.5.1 Data protection (RAM and Clock)
An internal rechargeable NiMH backup battery is fitted, which is trickle
charged from the main power source (eg the main battery) and used to
protect the contents of the RAM and clock if the main battery fails or is
removed.
This backup battery is recharged from the main battery whenever the
MP2500 is switched on and running (except in power save mode).
Depending on how much the MP2500 is used, it may take a long time to
charge a fully discharged backup battery - as long as 28 days or more.
If you need to charge the backup battery faster than this, connect the AC
adaptor - the backup battery will be fully recharged within approximately 72
hours, e.g. 5 overnight charging sessions. However, the backup battery will
be adequately charged for normal purposes after a single overnight
charging session.
This backup battery should not need replacing, and is not user-accessible.
A fully charged backup battery will support the RAM contents for 12-18
hours at normal room temperatures.
The calendar clock (RTC) also has its own dedicated Lithium backup cell,
which is non-rechargeable. Even if the main battery and backup battery are
fully discharged, this Lithium backup cell will maintain the clock for up to 10
years.
52 H MP2500 System Developer's Guide
USKY