About this replacement
Digital Ally DVM-500PL Series — 3.7V Li-ion Replacement Battery (135-0036)
This is a 3.7V 1100mAh Li-ion replacement cell for the Digital Ally DVM-500PL in-vehicle camera system, cross-referenced to OEM part number 135-0036. It also fits the DVM-750, DV-500ULTRA, and DVB-500 units. All four models share the same voltage rail, physical footprint, and connector pinout.
- DVM-500PL, DVM-750, DV-500ULTRA, DVB-500 platform: These units use the same 3.7V cell format and BMS handshake across the line. The shared connector and protection circuit spec means one cell covers the full group without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge passes on the DVM-500PL platform. The BMS accepted the cell without fault codes, and protection cutoffs triggered correctly at both ends of the charge curve.
- First-install charge cycle on the DVM-500PL: Run the first full charge through the camera unit itself, not an external charger. The DVM-500PL's onboard BMS maps the new cell's discharge curve during that initial cycle — skipping it can cause the battery indicator to read inaccurately for the first several sessions.
Why the DVM-500PL battery indicator reads full then drops suddenly
The DVM-500PL uses a voltage-threshold method to estimate charge level rather than coulomb counting. A new Li-ion cell has a slightly different discharge curve than a worn original, so the camera's fixed voltage thresholds don't map cleanly on the first few cycles. The indicator can sit at full until the cell crosses a threshold, then jump several bars at once. After two or three full charge-discharge cycles through the camera body, the readings stabilise.
DVM-500PL showing no battery detected after cell replacement
This happens when the BMS hasn't completed an initialisation handshake with the new cell. The fix is a full charge cycle via the camera's own charging port — not an external bay charger. Once the internal BMS completes that cycle, the camera registers the cell correctly. If the no-detection message persists after one full charge, confirm the cell is seated flush and the connector tab is making clean contact at all three pins.