Electrolux EFP31312 Replacement Battery 14.4V 3500mAh

Electrolux EFP31312 / Ultimatehome 300 — 14.4V Li-ion Replacement Battery (200GD-INR-H18650CH-4S1P)

This 14.4V 3500mAh Li-ion battery replaces the original pack in the Electrolux EFP31312, EFR31223, EP31-15GYA, and Ultimatehome 300 cordless stick vacuums. It slots into the same battery bay and connects through the same BMS handshake as the factory cell. Capacity is 3500mAh (50.4Wh) — matched to the original specification.

• EFP31312 and Ultimatehome 300 platform: These models share the same 14.4V rail, battery bay geometry, and BMS communication protocol. That is why a single cell covers all listed variants — the connector pinout and charge handshake are identical across the range.
• Bench tested on actual hardware: We cycled this cell through sustained motor load on a restricted nozzle to trigger the BMS overcurrent threshold. The protection circuit tripped and reset cleanly without latching off, confirming normal behaviour under blockage events.
• Dock charging behaviour on this vacuum: Do not leave the vacuum seated on the charging dock permanently. These Electrolux cordless models trickle-charge continuously when docked, which accelerates capacity fade in Li-ion cells. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

On the EFP31312, the motor draws significantly more current when the filter is partially blocked or the nozzle is restricted. That extra draw causes voltage to sag at the cell terminals before the state-of-charge indicator registers a low reading. The BMS reads terminal voltage, not state of charge directly, so the display lags behind real capacity under load. Clean or replace the filter first — if suction restores, the battery is not the cause.

Motor cutting out mid-clean and recovering after a short pause

This is a BMS overcurrent trip, not a dead battery. When sustained suction restriction forces the motor to pull beyond the cell's rated discharge current, the protection circuit cuts power to prevent cell damage. The BMS resets once current drops — which is why a 30-second pause brings the vacuum back. Check the filter and nozzle for blockage before assuming the battery is at fault. If the motor cuts out on an unobstructed run, verify the replacement cell is seated fully and the terminal contacts are clean and making firm contact.