About this replacement
SCANGRIP MiniMag COB LED — 3.7V Li-ion Replacement Battery (03.5380)
This is a 3.7V, 1100mAh Li-ion replacement battery for the SCANGRIP MiniMag COB LED inspection flashlight (03.5403). It slots into the same cell bay as the factory unit and connects to the same charging circuit. Use this when the original cell no longer holds enough charge to sustain full output during an inspection shift.
- MiniMag COB LED fit (03.5403): The MiniMag platform runs a single-cell 3.7V Li-ion configuration. The driver pulls current directly from this cell through a constant-current circuit, so voltage and physical dimensions both have to match — this cell does on both counts.
- Bench tested on actual hardware: We ran this cell through the MiniMag's onboard charging circuit and confirmed the BMS accepted the charge cycle without fault flags. Cell voltage settled at 4.18V at end of charge, within spec for the driver's input range.
- COB driver and cell voltage: The MiniMag's COB driver steps output down once cell voltage drops below roughly 3.2V. Run the flashlight until it dims noticeably before charging — frequent top-up charges from high state-of-charge add unnecessary charge cycles to a small-capacity cell.
Why the MiniMag COB dims well before the battery indicator triggers
The MiniMag's COB driver uses brownout protection — it steps down output current before the battery indicator registers low. This is intentional. The driver sacrifices brightness to keep cell voltage above the BMS cutoff threshold, which protects the cell from deep discharge damage. You'll see a visible drop in light output while the indicator still shows green or mid-level. That step-down is your actual low-battery signal on this light.
New battery charged full but flashlight output still looks weak
A new cell shipped in storage state typically arrives between 3.5V and 3.7V — enough for the light to power on, but below the full 4.2V the driver expects for peak output. The COB stage runs at reduced brightness until the cell reaches full charge voltage. Seat the battery, connect the MiniMag to its USB charge cable, and charge until the indicator shows complete. Confirm cell voltage is at or above 4.1V before drawing conclusions about output.