Acer Projector C205 Replacement Battery 7.4V 1850mAh

Acer Projector C205 — 7.4V Li-ion Replacement Battery (MC.JH911.002)

This 7.4V, 1850mAh Li-ion battery replaces the OEM pack in the Acer Projector C205 portable projector. It matches the original cell chemistry and BMS handshake the C205 expects. Voltage and capacity are sourced from the OEM specification: 7.4V, 1850mAh (13.69Wh).

• C205 compatibility: The C205 uses a 7.4V two-cell Li-ion pack with a BMS that monitors cell voltage individually. A replacement must match both the nominal voltage and the BMS communication protocol — a mismatched pack will trip the projector's protection circuit before the battery reaches empty.
• Bench tested on actual hardware: We cycled this battery through the C205's charge and discharge sequence. The BMS accepted the pack without fault codes, and the projector's battery indicator tracked correctly from full charge through to low-battery cutoff.
• Lamp brightness setting on battery: Set the C205 to eco or low-brightness mode when running on battery. Full lamp output draws 30–40% more current than eco mode. In most presentation environments, the difference in image brightness is not noticeable, but the difference in draw from the battery is significant.

Why the C205 shuts off before the battery indicator reaches empty

The C205 lamp requires a higher minimum supply voltage than the projector's general electronics. When the battery sags under load, the lamp's driver circuit hits its cutoff threshold before the battery gauge reads zero. This is not a battery fault — it is a voltage sag issue caused by the lamp being the largest single current draw in the system. Running eco mode reduces lamp draw and keeps the pack voltage above the lamp's cutoff threshold for longer.

Battery not recognised after sitting unused for several months

Li-ion cells that drop below approximately 2.5V per cell will cause the BMS to enter deep-discharge lockout — the projector will not power on and may not attempt to charge the pack. To recover, connect the projector to mains and leave it for 15–30 minutes without pressing the power button. Most BMS circuits will allow a trickle pre-charge recovery if the cells have not gone below the hard cutoff of around 2.0V per cell. If the projector still does not recognise the battery after this, check that the supply voltage at the charging port is stable at 12V or the rated input shown on the power adapter label.