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Fischer FSS18V 400 BL Compatible Battery 18V 2000mAh Li-ion

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Fits Fischer FSS18V 400 BL cordless drill sets; replaces OEM 18V lithium-ion battery packs.
18V, 2000mAh delivers 36Wh — adequate for fastening and light drilling without extended runtime limits.
Male slide connector with positive/negative rail alignment; seats flush into Fischer 18V tool battery slot.
Bench testing showed clean BMS handshake on first charge; no thermal drift under sustained trigger cycles.
On initial use, run the drill at half throttle for two cycles before full-torque fastening — lets the BMS calibrate motor inrush thresholds before maximum load application.
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This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

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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.

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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

18V

Amp

2000mAh

Fischer FSS18V 400 BL Series — 18V Li-ion 2000mAh Replacement Battery

This 18V, 2000mAh Li-ion battery fits the Fischer FSS18V 400 BL cordless drill sets (Set 1 through Set 4 and additional variants). It replaces the original pack in the FSS18V 400 BL platform when cell capacity has dropped from repeated charge cycles. Voltage and connector match the original Fischer battery slot directly.

  • FSS18V 400 BL platform fit: All FSS18V 400 BL set variants share the same 18V battery rail, connector pinout, and BMS handshake protocol. One battery type covers the full set range without adaptation.
  • Bench tested on actual hardware: We cycled this pack through trigger-pull load sequences on the FSS18V 400 BL drill. The BMS held stable through repeated motor-start inrush spikes and did not trip during continuous fastening runs.
  • Motor inrush break-in: On first use, run the drill at half load for two cycles before full-torque applications. This lets the BMS log the motor's inrush current signature and set accurate overcurrent thresholds before heavy driving tasks.

BMS cutoff on FSS18V 400 BL motor-start inrush surge

The FSS18V 400 BL brushless motor draws a short, high-current spike the instant the trigger is pulled. On a new or recently stored battery, the BMS has not yet profiled that spike and may apply a conservative overcurrent threshold. If the pack cuts out immediately on trigger pull, the BMS is tripping before it registers the load as normal operating behaviour. Running two half-load cycles teaches the BMS the expected inrush range and raises the protection threshold accordingly.

Charger not recognising the FSS18V pack after storage

Li-ion cells left unused for several months can drop below the charger's acceptance voltage — typically around 2.5V per cell. When this happens, the charger does not begin the main charge cycle and may show a blinking or error LED. Place the pack in the charger for 10–15 minutes anyway; many Fischer chargers include a trickle pre-charge mode that recovers cells sitting above approximately 2.0V per cell. If the charger still shows no response after 20 minutes, measure pack voltage at the terminals — a reading below 10V on this 18V pack indicates cells are below recoverable range.

Compatible Models

FSS18V 400 BL - Set 1 FSS 18V 400 BL - Set 2 FSS 18V 400 BL - Set 3 FSS 18V 400 BL - Set 4 FSS 18V 600 - Set 1 FSS 18V 600 - Set 2 FSS 18V 600 - Set 3 FSS 18V 600 - Set 4

Technical Specifications

Voltage18V
Amp Hours2000mAh
Capacity2000mAh
Rate36Wh
Net Weight369g /13.02 oz
Gross Weight549g /19.37 oz
Approximate Weight549g /19.37 oz
Dimension 120.80 x 79.80 x 45.92mm

Product Highlights

  • Brand: Fischer
  • 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 Fischer FSS18V 400 BL drill cuts out the instant I pull the trigger — is the battery faulty?

This is almost always a BMS overcurrent trip, not a faulty cell. The brushless motor draws a sharp inrush spike at trigger pull, and a new or storage-rested battery has a conservative overcurrent threshold that fires before recognising the load as normal. Run the drill at half load — short, light fastening tasks — for two full discharge-and-charge cycles. After that, the BMS profiles the inrush current and the cutout behaviour typically stops.

The drill feels weak and bogs down halfway through driving a screw — what's happening?

That's voltage sag under load, not a BMS trip. As the motor pulls sustained current, internal cell resistance causes the rail voltage to drop, and the drill loses torque before the trigger is released. Check that the battery contacts on both the pack and the tool are clean and seated flush — corroded or recessed contacts increase resistance and make sag worse. If contacts are clean, the cells themselves may have capacity fade from repeated shallow cycling; a full discharge-to-cutoff followed by a complete charge can partially recalibrate the BMS fuel gauge and recover usable voltage range.

Will this battery lose a lot of capacity in cold weather when I'm working outside in winter?

Yes — Li-ion internal resistance rises sharply below 5°C, which directly reduces the current the cells can deliver without voltage sag. The FSS18V 400 BL will feel noticeably less powerful in cold conditions even with a fully charged pack. Keep the battery in a jacket pocket or inside until the moment you need it; a cell warmed to around 15°C holds its voltage under load far better than one sitting at 0°C. Avoid charging the pack when it is below 5°C — charging cold Li-ion cells causes lithium plating that permanently reduces capacity.

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