PowerBook 100 Battery Replacement
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The PowerBook 100 has a sealed lead-acid main battery, which is not shared with any other PowerBook, and three lithium coin cells that back up the parameter RAM and clock.[1][2]
Main battery
[edit | edit source]| Item | Value |
|---|---|
| Type | Sealed lead-acid[1] |
| Voltage | 7 V (Service Source); the developer note's block diagram says 6.5 V[1][3] |
| Capacity | 2.5 Ah[3] |
| Run time | 2.5 hours maximum[1] |
| Service part | 661-0782, battery with case[1] |
Removing it
[edit | edit source]- Shut down with the Shut Down command and disconnect the adapter.[1]
- Put the elevation feet in the "up" position, slide the main battery cover to the right, pull on the right side of the cover and take the battery out.[1]
- The cover comes off the battery by prying its locking tabs apart with needlenose pliers and sliding it off.[1]
Testing and charging
[edit | edit source]Measure across the battery terminals on a meter's 10 V DC range; below 5.7 V, recharge or replace it.[1] Apple's external battery recharger runs from the PowerBook adapter: yellow means charging, green means ready, and no light means the charger is unplugged or the battery, adapter or charger is faulty.[1]
Apple's handling instructions: do not leave the battery in the computer for longer than a week without connecting the adapter, keep it in its case, do not store it for more than six months without recharging, and never short the terminals. Apple also warns against opening the plastic case, exposing the battery to flame or putting it in household rubbish, and says to wash skin for at least five minutes after touching a damaged battery.[1]
Rebuilding
[edit | edit source]Original packs are dead, and the third-party lead-acid packs sold in the 1990s have also failed with age.[4] Owners who rebuild them use lithium cells in the old case:
- MacPlus2300 used two 3.7 V lithium-ion cells in series with a 2S battery management board, and charges the pack outside the computer.[4]
- finkmac built a LiFePO4 pack with a battery management board that charges in the PowerBook, because LiFePO4 behaves more like lead-acid.[4]
- Frederick designed a 3D-printed ABS shell for two lithium polymer pouch cells with a management board and a regulator.[5]
aladds cautions that getting the PowerBook to charge a substitute safely is the hard part, and that the PowerBook 100 battery is not the same as the 140-180 battery.[4] Any lithium substitute needs its own protection board.
Power adapter
[edit | edit source]Apple's adapter specification is 85-270 V AC in and 7.0-7.6 V out, 7.5 V nominal, at up to 2 A (1.5 A nominal). Apple's test: 7.5-7.9 V between the inside (positive) and the outside of the plug, measured on the 10 V DC range.[1] The original 100-series adapters leak their capacitors; see PowerBook 140 Troubleshooting#Power adapter.
Backup batteries
[edit | edit source]The parameter RAM and clock are backed up by three lithium coin cells, industry-standard CR2430, which Apple's documents rate at 3.5 V each.[1][3] A dead set shows as lost Control Panel settings whenever the main battery is changed.[1]
Replacing them
[edit | edit source]- Leave the main battery in or the adapter connected while you work, so the parameter RAM is not lost.[1]
- Put the elevation feet down, press the latch and open the connector panel cover at the back.[1]
- Pry open the backup battery door and ease the cells out.[1]
- Fit three new CR2430 cells with the positive side of each facing up, and close the door.[1]
Apple warns that the lithium cells can explode if handled or discarded wrongly.[1] Removing every power source, including these cells, clears the time and other parameter RAM settings; Apple counts that as normal.[1]
Storage switch
[edit | edit source]A switch on the back of the PowerBook 100 disconnects all power for long-term storage. Using it clears the RAM disk and the parameter RAM, and a machine that will not start may simply have it set to off.[2][1]
Related pages
[edit | edit source]- PowerBook 100
- PowerBook 100 General Maintenance
- PowerBook 100 Troubleshooting
- PowerBook 140 Battery Replacement
- Battery Refurbishment
- Battery Explosion, Capacitor or Corrosion Damage
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 Apple Computer, PowerBook 100 Service Source, hosted here as File:PowerBook 100 Service Source.pdf (see PowerBook 100 Service Source). PDF page numbers: Electrical p. 10 (main battery sealed lead-acid, 7 V, 2.5 hours maximum; backup batteries three 3.5 V lithium cells, industry-standard CR-2430); Power Adapter p. 11; Power symptom charts pp. 16-18; Backup Batteries pp. 39-41; Main Battery pp. 44-45; Main Battery Cover pp. 46-47; Battery Recharger pp. 101-102; Battery Handling pp. 105-107; Battery Verification pp. 108-109; AC Adapter Verification pp. 110-111; Exploded View p. 116 (main battery with case 661-0782, main battery door 949-0365, backup battery door 949-0336).
- ↑ 2.0 2.1 Low End Mac, "PowerBook 100" (retrieved 2026-10-02). 7 V lead-acid battery unique to the PB 100; PRAM battery 3 × CR-2430; AC adapter 7.5 V, 1.5 A nominal; the rear switch shuts off all power and clears the RAM disk and PRAM. Secondary source.
- ↑ 3.0 3.1 3.2 Apple Computer, Macintosh PowerBook 100 Developer Note (1991), hosted here as File:PowerBook 100 Developer Note (1991).pdf (see PowerBook 100 Documentation). Features, p. 3: 2.5 Ah sealed lead-acid rechargeable battery, backup from three 3.5 V lithium batteries; block diagram labels the main battery "6.5V SLA".
- ↑ 4.0 4.1 4.2 4.3 68kMLA forum thread "My Simple DIY PowerBook 100 Battery Rebuild!", August 2026. MacPlus2300: original Apple battery and a 1994 third-party lead-acid pack both dead; rebuilt with two 3.7 V 3000 mAh lithium-ion cells and a 2S battery management board, charged externally; aladds: running from any supply of the right voltage is easy, charging safely in the PowerBook is harder, and the PB100 battery differs from the 140-180 battery; finkmac: built a LiFePO4 pack with a BMS that charges in the machine, LiFePO4 being similar in behaviour to lead-acid. Community repair reports.
- ↑ 68kMLA forum thread "Powerbook 100 Battery", May 2026. Frederick: two LiPo pouch cells in series, 2S BMS and a regulator in a 3D-printed ABS shell. Community project.