GARLYN SR-400 Replacement Battery 14.4V 3400mAh Li-ion

GARLYN SR-400 / SR-600 / SR-700 — 14.4V Li-ion Replacement Battery

This is a 14.4V, 3400mAh (48.96Wh) lithium-ion battery for the GARLYN SR-400, SR-600, and SR-700 cordless stick vacuums. It replaces the original pack when the cell no longer holds enough charge to run a full cleaning session. Same voltage, same form factor — slides into the battery slot the same way the original does.

• SR-400, SR-600, SR-700 compatibility: These three models run the same 14.4V battery rail and share an identical battery bay footprint. The connector pinout and BMS communication protocol are the same across the range, so one cell covers all three.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a SR-series unit. The BMS negotiated correctly with the charger, cell voltage held steady at 14.4V nominal, and the protection circuit triggered at the expected low-voltage cutoff without nuisance tripping.
• Dock charging habit for SR-series vacuums: Do not leave the vacuum sitting on the charging dock between uses. SR-series vacuums on continuous dock charge develop capacity fade faster than units charged only when the battery is depleted. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

This happens when the motor draws more current than the BMS expects — usually caused by a partially blocked filter rather than a weak battery. Restricted airflow forces the motor to work harder, pulling higher current and causing voltage to sag under load even when cell charge looks adequate. The BMS reads this as a low-voltage condition and throttles output. Clean or replace the filter first, then test again — if suction holds, the battery is not the problem.

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

This is a BMS overcurrent trip, not a dead battery. When suction is restricted — by a clogged filter, a blockage, or heavy carpet fibres — the motor sustains a high-draw stall that pushes current past the BMS trip threshold. The BMS disconnects to protect the cell, then resets after the thermal or current condition clears. Clear any blockage, check the filter, and confirm the floor head roller is not jammed before concluding the battery is at fault.