Waterpik SR-3000 Replacement Battery 2.4V 700mAh BK-4MCCE

Waterpik Sensonic Plus SR-3000 — 2.4V Ni-MH Replacement Battery (BK-4MCCE)

This is a 2.4V, 700mAh Ni-MH replacement battery for the Waterpik Sensonic Plus SR-3000 and SR-3000E electric toothbrush, and the 900 Sonic Toothbrush. It replaces part number BK-4MCCE when the original cell can no longer hold a working charge. Dimensions are 43.36 x 20.50 x 10.46mm — physically identical to the factory cell.

• SR-3000, SR-3000E, and 900 Sonic Toothbrush compatibility: All three models share the same internal cell format, voltage rail, and motor driver circuit. One battery covers the full group — no wiring or connector changes needed.
• Bench tested on actual hardware: We cycled this cell through the SR-3000 motor at full brush speed. The BMS held steady voltage delivery across multiple charge and discharge cycles with no cutoff events during normal brushing load.
• Base charger discipline on the SR-3000: Remove the toothbrush from the charging base once it reaches full charge. The SR-3000 uses inductive trickle charging — leaving it docked continuously pushes small charge currents into an already full Ni-MH cell, accelerating capacity fade faster than regular use cycles would.

Brushing power dropping before the SR-3000 shows a low battery

Ni-MH cells in sonic toothbrushes suffer voltage sag under motor load before the charge indicator registers a problem. The SR-3000's motor draws a short current spike at each brushing cycle — as the cell ages, internal resistance rises and voltage dips enough to reduce brush head speed noticeably. The indicator circuit reads resting voltage, not loaded voltage, so it shows green while the motor is already underperforming. Replacing the cell restores the low-resistance path the motor needs to hit full oscillation speed.

SR-3000 not charging on the base after battery replacement

The SR-3000 uses inductive charging — the coil in the base must align precisely with the coil in the handle. After a battery swap, if the handle casing is not fully reassembled and seated, the coil gap widens and charge transfer drops to near zero. Check that the handle clicks fully closed and sits flush on the base with no tilt. A properly seated unit should feel warm at the base contact point within 10–15 minutes, confirming inductive coupling. If the handle is correctly seated and still not charging, confirm the base output with a multimeter — it should read approximately 2.4V AC at the charging pins.