About this replacement
Canon Wordtank Z400 / Z800 / Z900 Series — 3.7V Li-Polymer Replacement Battery (DB-10)
This is a 3.7V, 1600mAh Li-Polymer replacement for the Canon DB-10 battery. It fits the Wordtank Z400, Z410, Z800, and Z900 electronic dictionaries. Swap it in when the original no longer powers the device through a full reading session.
- Wordtank Z400 / Z410 / Z800 / Z900 compatibility: All four models use the same DB-10 cell — same 3.7V rail, same flat Li-Polymer form factor, same connector footprint. One battery covers the full Wordtank Z-series range listed here.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Z400 platform. The BMS held cutoff at the correct low-voltage threshold and accepted a full charge without flagging a fault on the device's power management circuit.
- Contact seating after replacement: The Wordtank Z-series uses a flat Li-Polymer pack with a friction-fit connector. After installing, press the battery firmly down before closing the rear cover. A connector that is even slightly unseated will prevent the device from powering on at all — not just cause reduced capacity.
Why the Wordtank Z400 loses saved words and bookmarks after a battery swap
The Wordtank Z-series stores user data — saved vocabulary, bookmarks, and history — in RAM that is backed by battery voltage. When the battery is fully removed, that RAM loses power and the data is gone. This is not a fault with the replacement battery. Before pulling the old cell, export or photograph any saved content you need. Once the new DB-10 is seated and the device powers on, you can re-enter saved words manually.
Backlight not working after fitting a new DB-10
The backlight circuit on the Wordtank Z400 draws more current than the base display and requires the battery to be above a minimum threshold before it activates. If the replacement cell shipped in a partially discharged state, the display may work but the backlight stays off. Charge the battery fully via the device's USB port before testing backlight function. Once the cell reaches a full charge, the backlight should respond normally to the brightness control.