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Philips FC6401 18.5V Replacement Battery 2500mAh Li-ion

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From $66.99 USD $82.99
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Fits Philips FC6401, FC6402, and PowerPro Aqua stick vacuums; replaces OEM part INR18650X25.
18.5V and 2500mAh deliver full motor torque on carpet and hard floors throughout cleaning cycles.
Connector slides straight in with a locking tab — no rotation needed, seats flush every time.
We bench-tested this cell in the FC6401 motor circuit; BMS accepted load immediately without fault delay or cutoff lag.
Do not leave the vacuum on the charging dock continuously — sustained trickle charge degrades capacity faster than standard charge-and-remove cycles.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

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⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

18.5V

Amp

2500mAh

Philips FC6401 / PowerPro Aqua — 18.5V Li-ion Replacement Battery (INR18650X25)

This 18.5V Li-ion battery replaces the OEM pack in the Philips FC6401, FC6402, and PowerPro Aqua stick vacuum cleaner range. Capacity is 2500mAh (46.25Wh) — matching the original specification. It fits the FC6401/01 and related variants that share the same battery housing and connector.

  • FC6401 / FC6402 / PowerPro Aqua compatibility: These models run the same 18.5V motor rail and use an identical battery footprint, connector pin-out, and BMS communication protocol. One cell pack covers the full group.
  • Bench tested on actual hardware: We ran this pack through charge and discharge cycles on an FC6401 unit. The BMS handshook correctly with the Philips charger, and overcurrent protection tripped as expected under a simulated blockage load before recovering cleanly on restart.
  • Dock charging on the PowerPro Aqua: Do not leave the vacuum sitting on the charging dock continuously. The Philips dock does not cut trickle charge once full, and sustained low-current charge degrades cell capacity faster than normal cycle wear. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

The FC6401 motor draws harder when the filter is partially blocked — pulling more current than the BMS expects under normal load. This causes the battery voltage to sag earlier than the indicator reflects, and suction weakens noticeably while the LED still shows adequate charge. The indicator measures resting cell voltage, not load voltage, so the two can diverge. Clean or replace the filter first — if suction recovers, the battery is not the issue.

Motor cuts out mid-clean then restarts after a short pause

This is a BMS overcurrent trip, not a dead battery. When the vacuum runs with a blocked filter or a restricted nozzle, sustained high current draw pushes past the BMS protection threshold and the pack shuts output. The vacuum goes silent, then recovers after the BMS resets — usually within 10 to 30 seconds. Clear the blockage, check the filter, and restart. If the trip keeps recurring with a clean filter, measure resting pack voltage — it should read at or above 18.5V after a full charge.

Compatible Models

FC6401 FC6402 PowerPro Aqua Stick vacuum cleaner FC6401/01 PowerPro Aqua FC6401 PowerPro Aqua FC6402 PowerPro Aqua 18V FC6402/61

Replaces Part Numbers

INR18650X25

Technical Specifications

Voltage18.5V
Amp Hours2500mAh
Capacity2500mAh
Rate46.25Wh
Net Weight255g /8.99 oz
Gross Weight325g /11.46 oz
Approximate Weight325g /11.46 oz
Dimension 69.30 x 63.30 x 38.30mm

Product Highlights

  • Brand: Philips
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My FC6401 loses suction halfway through a clean but the battery light still shows full — is the battery failing?

Not necessarily. When the filter is partially blocked, the motor draws more current than rated and the cell voltage sags under that load — even though the indicator reads full at rest. Clean or replace the foam and mesh filters first. If suction returns to normal, the battery is fine; the filter was forcing the motor to work harder than the BMS tolerates long-term.

The vacuum cuts out suddenly, then works again after sitting for 30 seconds — what triggers that?

That's the BMS tripping on overcurrent, not a dead pack. A blocked nozzle or restricted filter forces the motor to pull sustained current above the protection threshold, and the BMS shuts output to protect the cells. It resets automatically after a short pause. Clear any blockage, clean the filter, and restart — if it keeps tripping on a clean filter and unrestricted airflow, charge the pack fully and check that voltage at the terminals reads at or above 18.5V before assuming a fault.

I left my PowerPro Aqua on the dock for several weeks and now the battery barely lasts — did the dock damage it?

Yes, continuous dock charging degrades Li-ion cells. The Philips dock does not stop trickle current once the pack is full, so cells sitting fully charged under low continuous current develop capacity fade faster than cells charged only when depleted. The damage is cumulative and partly irreversible in a degraded pack. Going forward, charge to full and remove the vacuum from the dock — only return it when the pack needs charging again.

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