About this replacement
Alcatel OT-980 Series — 3.7V Li-ion Replacement Battery (OT-BY70)
This is a 3.7V, 1000mAh Li-ion replacement battery for the Alcatel OT-980 and OT-981 series smartphones, including the OT-980A and OT-981A. It matches OEM part numbers OT-BY70, CAB3170000C1, and CAB31LL0000C1. Swap this in when the original cell no longer holds charge through a normal day of calls and messaging.
- OT-980 and OT-981 series compatibility: Both the OT-980 and OT-981 lines share the same battery bay dimensions, connector pinout, and BMS handshake protocol — that is why one cell covers over 40 model variants across the range.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on OT-980 hardware. The BMS negotiated correctly with the charge IC, hit the expected 4.2V full-charge cutoff, and held stable voltage under sustained modem and display load.
- Fuel gauge recalibration on first use: After installation, disable any fast-charge mode and run one complete discharge-to-charge cycle at standard current. This allows the fuel gauge IC to map the new cell's discharge curve before it tries to calculate state-of-charge accurately.
Sudden shutdown at 20–30% on the OT-980 after a cell swap
This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. When the new cell's voltage drops under load — during a call or screen-on burst — the IC misreads remaining capacity and triggers a low-voltage shutdown earlier than the percentage shown. The fix is one full discharge cycle without interruption, letting the coulomb counter reset against real cell data. After that cycle, the reported percentage and actual cutoff voltage should align at around 3.4–3.5V under load.
OT-980 won't power on after sitting in storage for months
Li-ion cells self-discharge in storage. If the cell dropped below approximately 2.5V, the BMS enters a lockout state to prevent damage and will refuse to pass current to the phone. Connect the phone to a charger and leave it for 15–20 minutes without attempting to power it on — the charge IC needs time to trickle current into the cell and bring it above the BMS re-enable threshold. Once the cell reaches roughly 3.0V, the BMS releases, the charge IC switches to normal CC/CV charging, and the phone will power on.