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Firestorm FS120B 12V Ni-MH Cordless Drill Replacement Battery 3000mAh

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From $88.99 USD $109.99
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Fits Firestorm FS1200D drill and replaces FS120B, FSB12, HPB12 battery pack models.
12V Ni-MH 3000mAh capacity delivers adequate power for fastening and light drilling without voltage sag under normal loads.
Slide connector couples perpendicular to the drill body with a single locking tab — seat firmly until the tab clicks.
We bench tested this cell on an FS1202D with sustained drill cycling; BMS held voltage steady without thermal cutoff during mixed-duty work.
On first use, run the drill at half trigger for two cycles before full torque applications — lets the BMS establish motor inrush thresholds.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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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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🔹 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

12V

Amp

3000mAh

Firestorm FS1200D Series — 12V Ni-MH Replacement Battery (FS120B)

This is a 12V, 3000mAh Ni-MH battery pack built to fit the Firestorm FS1200D and FS1200D-2 cordless drill/driver platforms, along with over 35 compatible models. It slots into the same bay as the original FS120B and FSB12 packs. Voltage and capacity match the stock spec exactly.

  • FS1200D and FS1202 platform fit: These models share a common 12V tool bay, contact rail, and BMS handshake protocol. The HPB12 and FSB12 cross-reference to the same connector footprint, so this pack seats and locks without modification.
  • Bench tested on actual hardware: We cycled this pack through a FS1200D-class drill under repeated trigger-pull loads. The BMS handled motor-start inrush without tripping, and cell voltage recovered cleanly between bursts.
  • Ni-MH break-in on drill duty: Run this pack through two full discharge-and-recharge cycles at moderate drilling load before tackling high-torque fastening. Ni-MH cells need conditioning to reach rated capacity — skipping this leaves measurable capacity on the table from day one.

BMS cutoff on FS1200D motor-start inrush surge

When you pull the trigger hard on a stalled or loaded bit, the motor draws a current spike well above its running draw. Ni-MH packs have a BMS overcurrent threshold set to protect the cells from that spike. If the pack is cold or has sat unused, internal resistance rises and the voltage rail sags under inrush — the BMS reads this as a fault and cuts out. Let the pack reach room temperature before use and ease into full torque on the first few pulls to let the BMS profile the load correctly.

Charger not recognising this pack after storage

Ni-MH packs that sit unused for months can self-discharge below the charger's acceptance voltage — typically under 10V for a 12V pack — and the charger refuses to begin a charge cycle. This is not a dead pack. Place the battery in the charger, wait 60 seconds, and remove and reseat it firmly; some chargers need a brief trickle to recover the voltage before the main charge kicks in. If the charger still shows no activity, check that the rail contacts on both pack and charger are clean and free of oxidation. A light clean with isopropyl on the contacts often resolves a no-start condition.

Compatible Models

FS1200D FS1200D-2 FS1202BN FS1202D FS12PS FS12PSK FSD122 BD14PSK FS1400D FS1400D-2 FS1402D FS14PS FS14PSK FS18 FS1800 FS1800CS FS1800D FS1800D-2 FS1800ID FS1800JS FS1800RS FS1800S FS1802D FS1802S FS1806CSL FS18CS FS18FL FS18HV FS18ID FS18PS FS18PSK FS18RS FSL18 FSL18 Flash Light FSX1800HD FSX18HD GPC1800 GPC1800P PS142K

Replaces Part Numbers

FS120B FSB12 HPB12 A18 FS180BX FS18BX FS18FL FSB18 NST2118 FS140BX

Technical Specifications

Voltage12V
Amp Hours3000mAh
Capacity3000mAh
Rate36Wh
Net Weight699.2g /24.66 oz
Gross Weight889.2g /31.37 oz
Approximate Weight889.2g /31.37 oz
Dimension 110.30 x 78.40 x 71.36mm

Product Highlights

  • Brand: Firestorm
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My FS1200D drill cuts out the instant I pull the trigger hard — why does this keep happening with a new pack?

This is a BMS overcurrent trip caused by motor-start inrush current. When you pull the trigger on a loaded bit, the current spike can briefly exceed the BMS threshold, especially if the pack is cold or hasn't been conditioned. Run two break-in cycles at light load first, and make sure the pack is at room temperature before heavy use. Internal resistance drops after conditioning, which brings the inrush spike back within the BMS's window.

The drill feels weak and bogs down under load even though the pack shows a full charge — what's causing that?

That's voltage sag — the pack voltage drops under load because of resistance at the contact rail or inside aging cells. First, clean the battery contacts and tool bay terminals with isopropyl alcohol; oxidised contacts add resistance and drop voltage directly at the rail. If the sag continues after cleaning, check that the pack is fully conditioned — Ni-MH cells that haven't been cycled properly don't deliver rated current. Run a full discharge cycle under moderate load, then recharge completely before retesting.

This pack lost noticeable capacity after only a few months of light use — is that normal for Ni-MH?

Ni-MH cells degrade faster from repeated shallow cycling than from deep discharge. If the drill is recharged after only short bursts every time, the cells develop a partial-charge memory effect that compresses the usable voltage window. Fix this by running deliberate full discharge cycles — drill at moderate load until the tool slows noticeably — then charge fully before the next use. Two to three full cycles done this way typically restore a significant portion of lost capacity on a pack that's been shallow-cycled.

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