Editing Psion Series 7 Battery Service (section)

== ⚠️ Safety ==

Read [[Battery Refurbishment]] before opening any lithium pack. This one holds '''three 18650 cells in series''', up to 12.6 V fully charged, and every cell is live at every stage of the work — there is no discharged state in which the job is safe.

Two hazards are specific to this machine:

* '''Switch the machine off before removing the main pack, and watch the screen while you do it''' — see [[#⚠️ Changing the main pack can wipe the machine|below]].
* '''Never wire cells directly to the pack's external contacts.''' The controller board balances the three cells; without it one will eventually be overcharged or over-discharged while the pack looks healthy.<ref name="libatt" />