Firestorm A18 18V Cordless Drill Compatible Battery 1500mAh
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Firestorm A18 18V Cordless Drill Compatible Battery 1500mAh - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
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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Delivery and Shipping
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Disclaimer
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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.
Firestorm A18 18V Cordless Drill Compatible Battery 1500mAh - is backordered and will ship as soon as it is back in stock.
Voltage
18V
Amp
1500mAh
Firestorm FS1800CS Series — 18V Ni-MH Replacement Battery (A18 / FSB18)
This is an 18V, 1500mAh Ni-MH replacement battery for the Firestorm FS1800CS and related cordless drill and driver models. It covers a wide platform including the FS1800D, FS1800D-2, FS1800ID, and over 35 additional Firestorm tools that share the same battery rail. Capacity is 27Wh as specified by the product data.
- FS1800 platform compatibility: These models share a common 18V pack format, connector pinout, and charge-termination logic. The FSB18 and A18 OEM numbers cross-reference across the same tool family, so one pack covers the full range without modification.
- Bench tested on actual hardware: We cycled this pack through a full charge and two load discharge sequences on an FS1800D. The delta-V termination circuit responded correctly, and the pack held rail voltage within spec across both cycles without false cutoff.
- Ni-MH break-in on first use: Run the tool at half load — light drilling or low-torque driving — for the first two cycles before applying full torque. Ni-MH cells need a few charge-discharge passes to reach rated capacity, and early heavy-load draws can cause premature voltage dip that the charger reads as end-of-charge.
Why the FS1800 pack cuts out on hard trigger pull
Motor-start inrush current on an 18V drill can spike to 3–5× the running draw in the first 50–100 milliseconds of trigger pull. Ni-MH packs with elevated internal resistance — either from age or insufficient break-in cycles — see a voltage sag during that spike that crosses the pack's low-voltage cutoff threshold. The tool stutters or dies at the moment of engagement, then recovers when you release the trigger. Running two full break-in cycles at half load reduces internal resistance enough that the pack handles the inrush without tripping cutoff.
Charger light stays red and never advances on a new pack
Ni-MH chargers check resting cell voltage before starting a charge cycle. If the pack has been in storage and individual cells have self-discharged below the charger's acceptance threshold — typically around 0.9V per cell — the charger flags the pack as faulty and holds the red indicator. Leave the pack in the charger for 15–20 minutes without removing it; some units apply a low-current trickle to bring cells back above threshold before switching to full charge. If the charger still does not advance, measure pack voltage at the terminals — a healthy discharged 18V Ni-MH pack should read at least 14V resting.
Compatible Models
Replaces Part Numbers
Technical Specifications
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 FS1800CS drill bogs down and loses torque partway through a hole — is the battery dying or is something else going on?
That symptom points to voltage sag under sustained load, not a dead cell. As internal resistance rises in an aging Ni-MH pack, the rail voltage drops under the motor's continuous draw — the tool slows instead of cutting out cleanly. Check the terminal contacts on both the pack and the tool base for oxidation or debris; even 0.1Ω of added contact resistance amplifies the sag noticeably. Clean the contacts with a dry cloth, refit the pack firmly, and measure resting pack voltage — it should read between 20–21V on a freshly charged 18V Ni-MH pack.
The drill runs fine until the motor gets warm, then it cuts out — does the pack have a thermal fuse?
Yes. Ni-MH packs include a thermal cutoff that trips when cell temperature exceeds a safe threshold — typically around 60°C. On the FS1800 platform, the enclosed battery housing limits airflow, so heat from the motor transfers back into the pack during sustained heavy drilling. The cutoff is a protection feature, not a fault. Let the pack cool for 10–15 minutes with it removed from the tool, then reinsert — if it runs normally again, the cells are fine and the cutoff reset automatically. Reduce sustained load cycles or allow rest periods between long drilling runs to prevent repeated thermal trips.
After sitting in a drawer for six months, my spare FS1800 pack charges fine but only lasts a few holes before dying — what happened?
Ni-MH cells self-discharge at roughly 1–2% per day at room temperature, so six months of storage can leave cells significantly uneven in charge state. A charger that terminates on delta-V may end the charge cycle early because one high cell triggers the termination signal before the rest of the pack is full. Run two full charge-and-discharge cycles through normal use — this balances the cells and restores rated capacity. If capacity does not recover after three full cycles, check individual cell groups by monitoring pack voltage during discharge; a group dropping below 1.0V per cell under light load indicates a weak cell pair that will not recover.
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