Philips PPX4350 Replacement Battery 3.7V 1500mAh Li-Polymer

Philips PPX4350 — 3.7V Li-Polymer Replacement Battery (AEC974241)

This is a 3.7V, 1500mAh Li-Polymer battery for the Philips PPX4350 portable projector. It replaces OEM part AEC974241 and restores battery-powered projection for presentations and video playback. The cell measures 43.00 × 40.00 × 8.20mm and fits the PPX4350's internal battery compartment.

• PPX4350 platform fit: The PPX4350 uses a slim Li-Polymer cell at 3.7V nominal to keep the chassis thin. The battery's BMS communicates with the projector's charge controller — voltage, cell format, and connector pinout all need to match exactly, which is why this cell is listed for the PPX4350 only.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on PPX4350 units. The BMS held cutoff at low-end voltage correctly, the projector recognised the battery without fault codes, and the charge LED cycled through to full as expected.
• Lamp brightness setting on battery: Set the PPX4350 to eco or low-brightness mode when running on battery. Full lamp output draws 30–40% more current than eco mode. The projector's minimum operating voltage is higher than the battery's empty threshold — high lamp draw accelerates voltage sag and triggers shutdown before the battery indicator reaches empty.

PPX4350 shutting off before the battery indicator reaches empty

The PPX4350's lamp requires a higher minimum supply voltage than the point at which the battery indicator shows empty. When current draw is high — full brightness, maximum volume — the battery's internal voltage sags under load faster than the indicator tracks. The projector's power circuit hits its cutoff threshold and shuts down even though the indicator shows charge remaining. Switching to eco mode reduces current draw and keeps cell voltage above the projector's cutoff threshold longer.

PPX4350 not charging when connected to mains

The PPX4350's internal charger is calibrated for a Li-Polymer cell at 3.7V nominal — it expects a specific charge profile to initiate current flow. If the replacement cell's voltage has dropped below approximately 2.5V from deep discharge, the charger may not detect a valid cell and will not start charging. Connect the projector to mains and leave it for 15–20 minutes without powering on; some charge controllers send a trickle current first to recover a deeply discharged cell before switching to full charge current. If the charge LED does not respond, the cell voltage has likely dropped below recovery threshold.