About this replacement
3GEN DermLite DL5 — 3.7V Li-ion Replacement Battery (147379)
This is a 3.7V, 3400mAh Li-ion replacement battery for the 3GEN DermLite DL5 dermatoscope. It fits the DL5 platform directly, using OEM part references 147379, DL5-B, DL5-1351, and DL5-1351A. If your DL5 is no longer holding charge or the original cell has degraded, this cell restores power to the device.
- DL5 platform fit: The DermLite DL5 uses a single-cell 3.7V Li-ion pack with a BMS handshake tied to the device charge IC. All four OEM part numbers listed above map to the same cell format — same connector pinout, same BMS communication profile.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles against the DL5 charge IC. The BMS reported correct state-of-charge, the protection circuit triggered at expected cutoff voltages, and the device completed its startup sequence without faults.
- Post-swap startup procedure: After fitting this battery, allow the DL5 to complete its full power-on self-test without interruption. The device runs a BMS verification at startup — cutting power mid-sequence logs a false battery fault that persists until the next clean reboot.
DermLite DL5 not completing boot sequence after battery swap
The DL5 runs a self-test at startup that checks cell voltage against an internal threshold. A new cell arriving slightly below that threshold — common after shipping and storage — can cause the boot sequence to stall or abort. This is not a fault with the battery itself. Charge the new cell to full before the first boot attempt, then power on and leave the device undisturbed until the self-test completes. The BMS learn cycle requires one full charge-discharge pass before the device treats the cell as fully verified.
Charge indicator stalls below 100% on first charge
The DL5 charge IC applies a conservative current limit when it detects a new or unrecognised cell. This is intentional — the IC holds the cell at a lower termination voltage on the first pass to condition the chemistry. The indicator will appear to plateau below full. Let the charge cycle run to natural termination without unplugging early. After one full cycle, the charge IC recalibrates and subsequent charges will reach the correct terminal voltage of 4.2V.