About this replacement
Alarm.com ADC-VDB770 / C-VDB770 Video Doorbell — 3.7V Li-Polymer Replacement Battery (3795)
This 3.7V 500mAh Li-Polymer battery replaces part number 3795 in the Alarm.com Video Doorbell lineup. It fits the ADC-VDB770, ADC-VDB770-S, and C-VDB770 Touchless Video Doorbell models. At 32.40 × 29.50 × 6.00mm, the cell matches the original footprint exactly.
- ADC-VDB770 and C-VDB770 platform: These models share the same voltage rail, connector pinout, and BMS handshake requirements — one cell covers all variants listed. The 3795 part number is common across the touchless and standard ADC-VDB770 hardware revisions.
- Bench tested on actual hardware: We ran this cell through charge cycles on the ADC-VDB770 platform and monitored BMS communication during motion-triggered recording events. The protection circuit held voltage within spec across combined IR LED and processor load spikes.
- First-install power cycle: After fitting this cell, power cycle the doorbell once through the Alarm.com app. The firmware must register the new cell before the motion recording log syncs correctly to cloud storage — skipping this step can cause missed clips after the first trigger.
ADC-VDB770 going offline in the Alarm.com app after battery swap
When the original cell drops below the BMS re-entry threshold, the doorbell loses its session token with the Alarm.com cloud. Fitting a fresh battery restores power, but the firmware does not automatically re-establish that token. The camera appears online at the hardware level but shows as offline or unresponsive in the app. Re-adding the device through the Alarm.com app — or triggering a soft reset via the doorbell's reset button — forces a new token handshake and clears the offline status.
App reporting 0% or incorrect charge level after installing the new cell
The ADC-VDB770 uses a voltage-threshold indicator, not a fuel gauge IC — it reads state-of-charge from cell voltage at fixed reference points, not from charge tracking. When a new cell first powers the unit, the firmware reads voltage mid-ramp and may display 0% or an arbitrary figure. Run one full charge cycle to 4.2V and let the doorbell discharge through normal operation — the indicator recalibrates against the new cell's voltage curve and displays an accurate percentage from that point forward.