Tobii Dynavox I-12 Replacement Battery 10.8V 5800mAh

Tobii Dynavox I-12 / I-15 — 10.8V Li-ion Replacement Battery (12004072)

This is a 10.8V, 5800mAh (62.64Wh) Li-ion replacement battery for the Tobii Dynavox I-12 and I-15 AAC communication devices. These are touch-screen speech synthesizers used daily by people with speech and motor disabilities. Getting the right cell chemistry and BMS compatibility matters — these devices run continuous monitoring cycles that stock cells must pass before normal operation begins.

• I-12 and I-15 shared battery platform: Both models run the same 10.8V battery rail with identical connector pinout and BMS handshake protocol. The charge controller expects the same cell chemistry signature on both units, so one replacement cell covers either device without modification.
• Bench tested on actual hardware: We ran this cell through the Dynavox startup self-test sequence and monitored BMS communication during the power-on verification cycle. The cell passed state-of-charge reporting and charge-termination handshake on first boot after a full initial charge.
• Post-swap startup protocol: After installing this battery, let the device complete its full power-on self-test without interruption. The Dynavox BMS runs a cell verification pass at startup — cutting power mid-sequence flags a false battery fault that persists until the next clean reboot from full charge.

Why the Dynavox I-12 reports a battery fault on a brand-new cell

The I-12 charge controller applies conservative state-of-charge thresholds tuned to aged OEM cells. A new cell has a slightly different internal resistance profile during the first few cycles, and the BMS can flag this as a fault rather than recognising it as a fresh cell. This is not a defective battery — it is the BMS learning the new cell's characteristics. Run one complete charge-to-discharge-to-full-charge cycle before treating any fault indicator as a genuine failure.

Charge indicator stuck below 100% after first full charge

On first charge, the Dynavox charge IC applies a reduced current ceiling to an unrecognised cell, which means the charge cycle terminates earlier than the nominal 62.64Wh full capacity. The display may show 93–97% and stop climbing. This is the charge controller being deliberately conservative — not a capacity defect. After the first full discharge to the low-battery threshold and a second full charge, the IC recalibrates its end-of-charge voltage and the indicator reaches 100% normally. Do not interrupt this second charge cycle; let it run to natural termination.