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Psion netBook Pro Battery Service

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Psion netBook Pro left side
Psion Teklogix product photograph of the netBook Pro in side view.

Battery service for the Psion netBook Pro. The netBook Pro has a 2200 mAh, 12.6 V Li-ion main pack and, in place of the Psion netBook's CR2032 coin cell, two user-replaceable alkaline AAA backup cells. Its battery gauge calibrates itself to the pack fitted.[1] Psion Teklogix's user manual documents the batteries, the gauge, the reset procedures and the expected battery life, and is the source for the manufacturer figures below.

Safety

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  • Read Battery Refurbishment before opening any lithium pack. The pack's cells are charged to 12.6 V in series and are live throughout the work.[2]
  • Always switch the netBook Pro off before removing the main battery.[3]
  • If both the main pack and the backup cells run flat, everything in internal memory is lost. Data in the Flash folder survives.[3][4]

Battery specification

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Psion netBook Pro power
Item Specification
Main battery Li-ion pack, 2200 mAh, 12.6 V.[5] OpenPsion describe it as the netBook's three-cell pack with higher-capacity cells.[6]
Running time 8 to 11 hours, depending on the backlight level and with no peripheral cards (Rev C).[2] Rev A of the manual gave 8 to 14 hours.[7]
Charging 3 to 4 hours at a constant rate, with no trickle or fast charge.[2]
Backup battery Two non-rechargeable alkaline AAA cells, replaceable by the user.[3] Designed to hold memory "for several hours".[1]
AC adapter Listed only as "Adaptor for battery charging"; the manual gives no rating.[5]

The 12.6 V figure is the charged voltage of three Li-ion cells in series. Psion quotes the netBook's pack as 10.8 V, 1500 mAh.[8]

Interchangeability with the netBook pack

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A netBook Pro tester reported in 2003 that he "swapped the two batteries into the respective units and have used them for a week without any problem".[9] The OpenPsion rebuild guide says the netBook Pro pack "differs from that of the netBook only in the mAh rating of the batteries used for the pack", and that the netBook's charger charges any pack to 12.6 V whatever its capacity.[6] Psionex sells one pack, the NB3000, for the netBook, netBook Pro and Series 7.[10] The two machines differ slightly in size: 235 × 182 × 37 mm for the netBook and 235 × 184 × 35 mm for the netBook Pro.[11][12]

Battery gauge and calibration

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The netBook Pro tracks the discharge and charge current and voltage of a pack over a full cycle, and uses this to estimate the remaining charge. The Battery tab of Power Properties shows one of three states:[13]

Battery gauge states[13]
Indicator Meaning Accuracy of the estimate
"Not calibrated" The pack has not been calibrated Not very accurate
"Calibrating" The machine is tracking a complete discharge and charge cycle Somewhat more accurate
(none) Calibration complete Should be very accurate

Once a pack is calibrated the machine refines its estimate on every full cycle, so the gauge follows an ageing pack. Psion Teklogix recommends charging a pack fully when first used, then discharging it fully before charging it again. A calibration cycle aborts if the adapter is plugged in or removed, and calibration during charging can also abort if the unit gets too hot.[13]

Calibration is lost, and "Not calibrated" returns, if:[13]

  1. the unit shuts off for low battery while the estimate is above 6 %;
  2. charging stops (charge current below 100 mA) while the estimate is below 94 %;
  3. the estimate reaches 0 % and the unit keeps running for more than 15 minutes; or
  4. the estimate reaches 100 % and the unit keeps charging at more than 100 mA for more than 15 minutes.

A pack that keeps returning to "Not calibrated" is behaving differently from the way the machine characterised it, which is what an ageing or re-celled pack does.

With the "Using multiple main battery packs" box ticked, the machine discards the calibration whenever a pack is removed and calibrates each pack afresh; unticked, it keeps the calibration. The Battery tab also shows the charge or discharge current, which may be up to ten seconds old.[13]

Changing the main pack

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Psion Teklogix's procedure:[1]

  1. Switch the netBook Pro off.
  2. Slide the battery pack latch towards the rear of the machine.
  3. Pull the battery away from the machine.
  4. Push in the replacement pack.

When the main pack runs down the machine switches off with enough charge left in the pack to preserve the system state; only if it discharges further do the backup cells take over.[13]

Changing the backup cells

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The backup compartment is on the left, above the keyboard.[3]

  1. Switch the netBook Pro off.
  2. Tilt the display slightly forward to reach the backup battery cover.
  3. Press down on the centre of the cover and slide it towards the front of the machine.
  4. Remove the AAA cells.
  5. Fit new alkaline AAA cells, observing the polarity marking.
  6. Slide the cover back while pressing down on its centre.

For a hard reset, remove the backup cells before the main pack and refit them last, so they are not drained.[14] Alkaline cells can leak; take them out before long storage and see Battery Explosion, Capacitor or Corrosion Damage if the compartment is corroded.

Battery life and ageing

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Psion Teklogix's figures for the pack:[2]

  • Li-ion batteries do not fail suddenly unless abused; capacity falls gradually.
  • Capacity typically falls by about 15-20 % of the initial figure over 400 charge and discharge cycles.
  • Capacity also falls slowly with age in storage.
  • A pack is conventionally at end of life when its capacity has fallen to 50 %, typically after about 1000 cycles, although it will still work for some time after that.

Running time

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Psion Teklogix's advice for longer running time:[15]

  • Turn the screen brightness down.
  • Set Switch to Suspend to 10 minutes in the Battery Power scheme.
  • Open and use files from internal storage instead of a memory card; writing to cards uses more power.
  • Remove communications cards when not in use.

The three power scheme timeouts, Switch to Dim, Switch to Stand-By and Switch to Suspend, are cumulative: the unit suspends only after all three have elapsed in turn. Psion Teklogix recommends starting with a total of 10 minutes. The unit wakes from Dim and Stand-By almost instantly, and with all three set to Never it stays on.[16]

Protecting data

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Data in the Flash folder survives the discharge of both batteries and a soft or hard reset.[4] Rothberger measured about 10 MB of such non-volatile storage.[17] The Flash folder is also the backup location for Psion Teklogix's Total Recall utility, which can restore automatically after a hard reset but cannot extract individual files from a backup.[4][17]

Rebuilding the pack

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No rebuild guide specific to the netBook Pro is known. OpenPsion describe its pack as the netBook pack with higher-capacity cells, so the procedure on Psion netBook Battery Service applies.[6] The netBook Pro's cells were 2200 mAh from the factory,[5] so a rebuild with 2200 mAh cells restores the original capacity; on a 1500 mAh netBook pack the same cells increase it. A collector who planned to re-cell a netBook Pro pack in 2023 chose to spot weld the cells;[18] see Battery Refurbishment.

If you are rebuilding a dead pack, the battery management controller seems to go into a "storage or transport" mode which cuts power to the gold pads. If you replace the cells, the voltage is correct across the pack but you receive no voltage on the gold pads, follow the jump start procedure below.

  • Solder two lengths of wire to the pads on the back of the board (where the gold pins connect to). ENSURE THE POLARITY IS CORRECT!
  • Set a bench power supply to 12.6v at 200mA.
  • Supply power to the pack for approximately 20 seconds.
  • Check for voltage from the pack once bench power is removed.

After fitting a rebuilt pack, calibrate it with a full charge followed by a full discharge.[13]

Buying a pack

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Psionex in Lincoln lists the NB3000 main battery for the netBook, netBook Pro and Series 7. When checked in September 2026 it was out of stock.[10] AAA alkaline cells are a standard part.

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References

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  1. ↑ 1.0 1.1 1.2 Psion Teklogix, NETBOOK PRO User Manual, P/N 8100012 Rev C, 27 May 2004, pp. 16-18 (power management, main and backup batteries). Hosted on this wiki: File:Psion netBook Pro User Manual (Rev C).pdf.
  2. ↑ 2.0 2.1 2.2 2.3 NETBOOK PRO User Manual Rev C, p. 121 (battery life; charging times).
  3. ↑ 3.0 3.1 3.2 3.3 NETBOOK PRO User Manual Rev C, p. 18 (the internal backup battery).
  4. ↑ 4.0 4.1 4.2 NETBOOK PRO User Manual Rev C, p. 65 (The Flash folder).
  5. ↑ 5.0 5.1 5.2 NETBOOK PRO User Manual Rev C, p. 134 (power requirements).
  6. ↑ 6.0 6.1 6.2 OpenPsion, "Rebuilding a netBook's Lithium-Ion Battery". Retrieved 2026-09-30.
  7. ↑ Psion Teklogix, NETBOOK PRO Win CE 4.2 User Manual, P/N 8100012 Rev A, 10 October 2003, title page and p. 116 (power requirements). Hosted on this wiki: File:Psion netBook Pro User Manual (Rev A).pdf.
  8. ↑ Psion Computers PLC, netBook User Guide (December 1999), p. 205 (specification). Hosted on this wiki: File:Psion netBook User Guide (December 1999).pdf.
  9. ↑ "Netbook Pro battery?", comp.sys.psion.misc, 2003.
  10. ↑ 10.0 10.1 Psionex, "Batteries - Netbook & Series 7". Retrieved 2026-09-30.
  11. ↑ Psion Teklogix, "netBook" product datasheet, NBOOK-01/01-5K-A4-UK, February 2001. Hosted on this wiki: File:Psion netBook Datasheet (2001).pdf.
  12. ↑ NETBOOK PRO User Manual Rev C, p. 133 (physical specifications).
  13. ↑ 13.0 13.1 13.2 13.3 13.4 13.5 13.6 NETBOOK PRO User Manual Rev C, pp. 21-22 (Power Properties: battery tab, battery calibration).
  14. ↑ NETBOOK PRO User Manual Rev C, pp. 33-34 (soft and hard reset).
  15. ↑ NETBOOK PRO User Manual Rev C, p. 16 (power management).
  16. ↑ NETBOOK PRO User Manual Rev C, pp. 22-24 (power saving schemes).
  17. ↑ 17.0 17.1 Jürgen Rothberger, "Review: Psion Netbook Pro" (in German), July 2007. Retrieved 2026-09-30.
  18. ↑ hassilon, post of 28 September 2023, in "How bad is the 'hinge defect' on the Psion Teklogix Pro Netbook?", HPC:Factor forums. Retrieved 2026-09-30.


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