Media-Tech MT4039 Compatible Battery 3.7V 1050mAh Li-ion

Media-Tech MT4039 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1050mAh Li-ion replacement battery for the Media-Tech MT4039 compact digital camera. It slots into the same battery compartment as the original cell and supports image and video capture. Capacity is rated at 3.89Wh.

• MT4039 battery compartment fit: The MT4039 uses a slim 53.20 × 35.30 × 7.10mm cell format. This replacement matches those dimensions exactly, so the compartment door closes and the contact pins seat without adjustment.
• Bench tested on actual hardware: We cycled this cell through the MT4039's charge and draw circuit. The BMS held cutoff at the correct low-voltage threshold and accepted a full charge from both the camera body and an external single-cell Li-ion charger.
• First-cycle initialisation on the MT4039: Run one complete charge cycle through the camera body before your first shoot. The MT4039's battery-remaining indicator maps voltage thresholds from within the body — skipping this step can cause the percentage display to jump or read inaccurately until the BMS has a full charge reference point.

Flash recycling slowing down before the battery indicator hits low

The MT4039's flash capacitor pulls a short but sharp charge current each time it recycles between shots. As a Li-ion cell approaches the lower portion of its discharge curve, internal resistance rises and the voltage sags briefly under that capacitor recharge load. The camera body may not flag low battery yet — the indicator reads mid-range — but flash recycle time noticeably lengthens. If you are shooting in burst or high-frequency flash conditions, treat slower recycle time as an early signal to swap the cell, even if the indicator has not reached red.

Battery percentage jumping erratically on the MT4039 display

This happens when the camera's voltage-to-percentage mapping table does not yet have a full discharge profile for the new cell. The MT4039 reads cell voltage and translates it to a percentage using a fixed lookup — a new replacement cell with a slightly different discharge curve can cause the readout to skip between values. The fix is one full charge-to-discharge cycle through the camera body. After that single calibration cycle, the indicator tracks the cell's actual state of charge accurately. Charge fully via the camera body until the charge indicator clears, then shoot until the camera shuts off on low-voltage cutoff.