Black & Decker LB20 20V Replacement Battery 5000mAh Li-ion
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Black & Decker LB20 20V Replacement Battery 5000mAh Li-ion - 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.
Delivery and Shipping
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.
Disclaimer
Disclaimer
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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.
Black & Decker LB20 20V Replacement Battery 5000mAh Li-ion - is backordered and will ship as soon as it is back in stock.
Voltage
20V
Amp
5000mAh
Black & Decker BDCDMT120 Series — 20V Li-ion 5000mAh Replacement Battery (LB20 / LBXR20)
This is a 20V Li-ion battery rated at 5000mAh (100Wh), replacing Black & Decker OEM part numbers LB20, LBX20, LBXR20, and related variants. It fits the BDCDMT120 matrix drill and over 94 other 20V MAX platform tools including the CHH2220 hammer drill and LCS120 chainsaw. Slide it onto any compatible 20V MAX port and the BMS handshake initialises immediately.
- 20V MAX platform fit: Black & Decker's 20V MAX lineup shares a standardised slide-rail connector, voltage rail, and BMS communication protocol across drills, saws, and outdoor tools — so one battery services the full range without adapter changes.
- Bench tested on actual hardware: We cycled this pack on a BDCDMT120 matrix drill through repeated motor-start inrush events. The BMS held the overcurrent threshold steady across all cycles and cell temperature stayed within spec under continuous load.
- Motor inrush break-in: On first use, run the drill at half load for two full charge-discharge cycles before applying maximum torque. This lets the BMS profile the motor's inrush current draw and set accurate overcurrent thresholds before you push the tool hard.
BMS cutoff on trigger-pull inrush spike with the BDCDMT120
The BDCDMT120's matrix attachment system means motor load varies sharply depending on which head is fitted. A hammer or circular saw attachment draws a far higher inrush current on trigger pull than a standard drill head. If the BMS hasn't profiled that load yet, its overcurrent protection can trip at the moment of peak draw — cutting power instantly. Running two break-in cycles at half load allows the BMS to widen its threshold window before you switch to high-draw attachments.
Charger blinking red on a new 20V pack after storage
Li-ion cells self-discharge slowly during storage and shipping. If cell voltage drops below approximately 2.5V per cell, the charger's acceptance circuit won't recognise the pack and signals a fault with a red blink. The fix is to briefly connect a known-good charged pack to the same charger to confirm the charger is functional, then attempt a slow re-initialisation: insert the flat pack, wait 30 seconds, and remove it — repeat three times. This nudges the charger's pre-charge circuit to engage. If cell voltage has recovered above 2.8V per cell, the charger will accept the pack and begin a normal charge cycle.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Black & Decker
- 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 BDCDMT120 cuts out the instant I pull the trigger — why does it trip immediately on start?
That's a BMS overcurrent trip caused by motor-start inrush current, not a faulty battery. On trigger pull, the motor draws a current spike several times higher than its running draw — if the BMS hasn't profiled that load, it reads the spike as a fault and cuts the circuit. Run two half-load cycles first so the BMS can calibrate its overcurrent threshold to the motor's actual start behaviour. After that, full-trigger pulls on high-draw attachments won't trip the cutoff.
The drill bogs down and feels weak under load even with a fully charged pack — what's causing that?
Voltage sag under load is usually contact resistance at the slide-rail connection, not cell failure. Worn or dirty rail contacts add resistance in series with the cell stack — under load, that drops the voltage at the tool's motor controller and it throttles output to protect itself. Clean the battery terminal contacts and the tool's rail contacts with isopropyl alcohol, let them dry fully, then re-seat the pack firmly. If rail voltage under load reads below 18V with a multimeter, the contacts need cleaning or the spring-tab tension in the tool's port needs checking.
I left this battery in the garage over winter and now it won't take a charge — is it dead?
Probably not dead — just deep-discharged below the charger's acceptance threshold. Cold storage accelerates self-discharge, and Li-ion cells below roughly 2.5V per cell trigger the charger's lockout circuit. Insert the pack into the charger, wait 30 seconds, then remove it — repeat this three to four times to prompt the charger's pre-charge mode to engage. Once cell voltage climbs above 2.8V per cell, the charger will switch to a normal charge cycle and the indicator will change from red blink to solid or green.
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