Editing Psion Series 7 Battery Service

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Battery service for the '''[[Psion Series 7]]'''.

'''The Series 7 and the [[Psion netBook|netBook]] use the same battery pack''', so the rebuild procedure is written once, on the [[Psion netBook Battery Service]] page, and is not repeated here. Go there for the pack teardown, cell selection, spot welding and reassembly.

This page covers what is specific to the Series 7: how the machine treats its pack, the charging indications that get misread as faults, and the one procedure that destroys your data if you get it wrong.

{{Main|Psion netBook Battery Service}}

== ⚠️ 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" />

== What the Series 7 takes ==

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''Psion Series 7 power'''
! Item !! Specification
|-
| '''Main battery''' || Proprietary Li-ion pack, '''three 18650 cells in series''' with a controller board. '''11.1 V nominal, 1500 mAh''' as Psion specified it; the Series 7 FAQ describes the same pack as "three 3.6v graphite-type Li-Ion cells"<ref name="faqpower">[https://www.oocities.org/epoc_32/power.html "Psion Series 7 FAQ: Power supply & charging"], oocities.org/epoc_32 (February 2000). Source for the "sealed, non-serviceable unit" description, the cell description, the runtime figures, the charging behaviour and the 70 % LED cut-out, the three-monthly storage charge, the adapter rating and the ferrite core.</ref><ref name="openpsion">OpenPsion, [https://linux-7110.sourceforge.net/howtos/netbook_new/x43.htm "Linux on the Psion netBook HOWTO — section 3.4, The netBook Specifications"]. Source for the 11.1 V 1500 mAh rating, the CGR18650H cell type, the CR2032 backup cell and the adapter connector dimensions.</ref>
|-
| '''Backup battery''' || '''CR2032''' lithium coin cell<ref name="openpsion" />
|-
| '''Mains adapter''' || '''15.5 V, 1.5 A''', 100–240 V 50/60 Hz, ferrite core on the lead. Connector 4.75 mm OD / 1.75 mm ID<ref name="faqpower" /><ref name="openpsion" />
|-
| '''Runtime''' || 8½ hours quoted; over 10 hours at lowest brightness with no peripherals. Roughly '''50 % less at full brightness'''<ref name="faqpower" /><ref name="faqgen">[https://www.oocities.org/epoc_32/general.html "Psion Series 7 FAQ: General & hardware information"], oocities.org/epoc_32. Source for the brightness/runtime relationship, the charging LED sequence, the absence of display dimming as the battery drains, and the reset procedures.</ref>
|-
| '''Charge time''' || Up to 3 hours, machine on or off<ref name="faqpower" />
|}

'''The Series 7 does not run on AA cells and never did.''' There is no alternative internal power source.<ref name="faqpower" />

'''Do not substitute another Psion mains adapter.''' No other EPOC or SIBO machine's supply matches 15.5 V at 1.5 A — the comparison table is on the [[Psion netBook Battery Service#Do not use another Psion adapter|netBook battery page]].<ref name="faqpower" />

== Psion called the pack non-serviceable ==

Worth knowing before you open one, because it explains why there is no factory procedure to follow. The contemporary FAQ describes the pack as '''"a sealed, non-serviceable unit"'''.<ref name="faqpower" />

The community rebuilt them anyway, and has done since at least 2003 — see [[Psion netBook Battery Service]]. Psion's position simply means you are on your own, and that the case has internal locks you will break getting in.

== Reading the charge LEDs ==

Three-quarters of "my battery won't charge" reports on these machines are this behaviour, correctly working:<ref name="faqgen" /><ref name="faqpower" />

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''What the LEDs mean'''
! Indication !! Meaning
|-
| '''Right-hand LED green''' || Mains power present. Normal whenever the adapter is connected.
|-
| '''Right-hand LED yellow, red LED to its left glowing''' || Charging. '''The brighter the red LED, the more charging remains.'''
|-
| '''Red LED dimming over time''' || Charge progressing normally.
|-
| '''Red LED out, yellow returned to green''' || '''The battery is well charged but not to full capacity.''' The LED cuts out at about '''70 %'''.
|}

The practical consequence: '''charge for the full three hours rather than until the light goes out.''' A pack that seems to be losing capacity is very often simply never being filled.<ref name="faqpower" />

Two related behaviours that are also normal:

* '''The display does not dim as the battery drains.''' There is a slight brightness boost when the adapter is plugged in, and that is all.<ref name="faqgen" />
* '''The machine stops abruptly rather than degrading.''' Li-ion machines cut out well before the cells are exhausted, so unlike an alkaline machine you keep full function — audio, CompactFlash writes, the serial port — right up to the moment it stops.<ref name="faqgen" />

== ⚠️ Changing the main pack can wipe the machine ==

'''This is the most important thing on this page.'''

The internal C: drive is RAM. A microswitch in the battery lock is meant to switch the machine off as you release the catch, leaving the CR2032 to hold the contents. '''On some machines it turns the backlight on instead''' — the screen lights but stays black, the system never shuts down, and pulling the pack draws more than the coin cell can supply. The machine cold-boots and the internal disk is gone: data, applications, settings and, on a netBook, the operating system.<ref name="faqbugs">[https://www.oocities.org/epoc_32/bugs.html "Psion Series 7 FAQ: Known issues & bugs"], oocities.org/epoc_32. Source for the battery-catch microswitch fault, the data loss it causes, the safe removal procedure and the rubber foot on the battery catch.</ref>

'''The safe procedure every time:'''

# '''Back up first''' — to CompactFlash or a PC.
# Slide the catch back and '''look at the screen'''.
# If it lights but stays black, '''hold the catch open with one hand and switch the machine off with the other'''.<ref name="faqbugs" />
# Only then remove the pack.
# Change one battery at a time. With both out, RAM is gone regardless.

And check the catch itself: '''one of the rubber feet is mounted on the underside of the battery catch''', and sliding the machine across a desk or carrying it loose in a bag has been enough to drag the catch open and reset the machine.<ref name="faqbugs" />

== The backup cell ==

A standard '''CR2032''', still made in quantity and available anywhere, including badged for the machine by battery specialists.<ref name="psionex">[https://psionex.co.uk/en/product/pda/netbook/batteries.html "Batteries — Netbook & Series 7"], Psionex, Lincoln. Source for the CR2032 and NB3000 stock position described. Stock changes; check before relying on it.</ref>

Replace it on a schedule rather than on failure. It is what holds your data while the main pack is out, and it is the cheapest component in the machine.

== Storage ==

* '''Give a stored pack a full three-hour charge every three months.'''<ref name="faqpower" />
* '''Do not buy spare packs to keep.''' Lithium cells age from their date of manufacture, not from first use, so a "new old stock" pack from 2003 is a 23-year-old pack.<ref name="libatt">OpenPsion, [https://linux-7110.sourceforge.net/howtos/netbook_new/LIbattery/LIbattery.html "Rebuilding a netBook's Lithium-Ion Battery"]. Source for the ageing-from-manufacture point, the absence of memory effect and the charge-controller behaviour.</ref>
* '''There is no memory effect''' on these cells; partial charging does them no harm and full discharges do.<ref name="faqpower" /><ref name="libatt" />

== Rebuilding ==

The full procedure — opening the pack, choosing cells, spot welding, transferring the controller board, reassembly and first charge — is on the '''[[Psion netBook Battery Service]]''' page, and applies unchanged to the Series 7. The rebuilder who wrote the community guide did the work on a Series 7 and got '''12½ hours from 2200 mAh cells''' where the original pack managed 7.<ref name="libatt" />

Read [[Battery Refurbishment]] before starting. It covers the safety, cell selection and welding technique that this family of guides depends on.

== Related pages ==

* [[Psion Series 7]] · [[Psion Series 7 General Maintenance]] · [[Psion Series 7 Troubleshooting Guide]]
* '''[[Psion netBook Battery Service]]''' — the rebuild procedure for this pack
* [[Psion netBook Pro Battery Service]] · '''[[Battery Refurbishment]]'''
* [[Battery Explosion, Capacitor or Corrosion Damage]] · [[Recommended Tools]]

== References ==

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[[Category:Psion]]
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