Psion Series 7 Battery Service
Battery service for the Psion Series 7.
The Series 7 and the 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.
What the Series 7 takes
| 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"[1][2] |
| Backup battery | CR2032 lithium coin cell[2] |
| 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[1][2] |
| Runtime | 8½ hours quoted; over 10 hours at lowest brightness with no peripherals. Roughly 50 % less at full brightness[1][3] |
| Charge time | Up to 3 hours, machine on or off[1] |
The Series 7 does not run on AA cells and never did. There is no alternative internal power source.[1]
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 netBook battery page.[1]
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".[1]
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:[3][1]
| 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.[1]
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.[3]
- 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.[3]
⚠️ 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.[4]
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.[4]
- 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.[4]
The backup cell
A standard CR2032, still made in quantity and available anywhere, including badged for the machine by battery specialists.[5]
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.[1]
- 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.[6]
- There is no memory effect on these cells; partial charging does them no harm and full discharges do.[1][6]
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.[6]
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
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 "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.
- ↑ 2.0 2.1 2.2 OpenPsion, "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.
- ↑ 3.0 3.1 3.2 3.3 "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.
- ↑ 4.0 4.1 4.2 "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.
- ↑ "Batteries — Netbook & Series 7", Psionex, Lincoln. Source for the CR2032 and NB3000 stock position described. Stock changes; check before relying on it.
- ↑ 6.0 6.1 6.2 OpenPsion, "Rebuilding a netBook's Lithium-Ion Battery". Source for the ageing-from-manufacture point, the absence of memory effect and the charge-controller behaviour.