About this replacement
Motorola K1m / A3100 / Evoke QA4 — 3.7V Li-ion Replacement Battery (SNN5782)
This is a 3.7V, 880mAh Li-ion replacement battery for the Motorola K1m, A3100, Evoke QA4, Tundra VA76R, and compatible models. It replaces OEM part numbers SNN5782, SNN5782B, SNN5762, SNN5762A, BT60, SNN5819, SNN5819B, HKNN4014, and HKNN4014A. If your original cell has degraded or failed, this is the direct swap.
- Cross-model fit — K1m, A3100, Evoke QA4, Tundra VA76R: These devices share the same 3.7V single-cell architecture, BMS handshake protocol, and connector pinout. One cell covers the full lineup because the charge IC and protection circuit requirements are identical across the platform.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the A3100 platform. The BMS accepted the cell without triggering over-voltage or under-voltage cutoff, and the protection circuit responded correctly to simulated load spikes from the radio and display.
- Fuel gauge recalibration on first install: On first use after installation, run one complete discharge-charge cycle with fast charging disabled. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging begins against an uncalibrated reference.
Sudden shutdown at 20–30% on the K1m and A3100
This is the most common complaint after a cell swap on these devices. The fuel gauge IC still holds the discharge curve of the old, degraded cell in memory. When the new cell hits a voltage point the IC associates with near-empty, it signals shutdown even though actual capacity remains. One full discharge-charge cycle without interruption forces the coulomb counter to rewrite its reference curve. After that cycle, the reported percentage tracks the real state of charge accurately.
Phone not powering on after the battery sat in storage
Li-ion cells that drop below approximately 2.5V per cell trigger BMS lockout as a protection measure. A cell stored for months in a discharged state can hit this threshold. The phone will not respond to the power button and may show no charging indicator when first connected. Connect to a known-good charger and leave it undisturbed for 20–30 minutes — the BMS pre-charge circuit will trickle current in at a low rate until cell voltage rises above the lockout threshold, typically around 3.0V, at which point normal charging resumes.