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Teufel Boomster 2020 Replacement Battery 11.1V 5200mAh

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From $53.99 USD $66.99
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Fits Teufel Boomster 2020 speaker; replaces OEM battery ICR18650 module.
11.1V, 5200mAh lithium-ion delivers full output current to amplifier and Bluetooth radio without voltage sag.
Connector seats flush into speaker chassis with no orientation issues; locking tab secures pack against vibration during transport.
We bench-tested the cell under sustained 5A load at volume peak; BMS held steady at 11.1V with clean discharge curve across full capacity window.
Discharge this pack to below 20% once monthly before recharging — constant top-off charging causes fuel gauge drift and accelerates capacity fade on the Li-ion cell.
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.

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

11.1V

Amp

5200mAh

Teufel Boomster 2020 — 11.1V Li-ion Replacement Battery (ICR18650)

This 11.1V, 5200mAh (57.72Wh) Li-ion battery replaces the original pack in the Teufel Boomster 2020 portable Bluetooth speaker. It restores wireless audio playback when the factory cell has degraded or failed entirely. The ICR18650 module matches the original's voltage rail and connector configuration for the Boomster 2020 platform.

  • Boomster 2020 platform fit: The Boomster 2020 runs its amplifier board and Bluetooth radio from a single 11.1V three-cell Li-ion pack. Both subsystems share this voltage rail, so a sagging or dead pack affects audio output and wireless connectivity simultaneously — not independently.
  • Bench tested on actual hardware: We cycled this pack through the Boomster 2020's charge and discharge circuit, confirming the BMS communicates correctly with the speaker's fuel gauge. Cell balance across all three ICR18650 cells stayed within 20mV at full charge.
  • Monthly discharge cycle for Boomster 2020: If the speaker sits on a desk and gets topped off constantly, discharge it below 20% at least once a month before recharging. Constant shallow top-off cycling causes fuel gauge drift on the 11.1V pack and accelerates capacity fade.

Why the Boomster 2020 audio clips and distorts before the battery indicator reads empty

The Boomster 2020's amplifier draws a sharp current spike at high volume. When the Li-ion pack is aged or partially degraded, internal resistance climbs and the pack voltage sags under that spike — even while the fuel gauge still shows charge remaining. The amplifier hits its minimum operating voltage and clips the audio signal before the battery indicator acknowledges the pack is low. Replacing the pack with a fresh 5200mAh cell reduces internal resistance and eliminates the voltage sag causing the clip.

Boomster 2020 not waking from USB-C after sitting unused for weeks

If the Boomster 2020 sits unused long enough, the Li-ion pack self-discharges below the USB-C PD minimum acceptance voltage — typically under 2.5V per cell, or around 7.5V pack total. At that level, the charger handshake fails and the speaker appears completely dead. Connect the USB-C cable and leave it for 15–20 minutes without pressing any button; most BMS circuits include a trickle pre-charge mode that recovers the cells to a voltage where normal charging resumes. If the pack does not respond after 30 minutes, the cells have over-discharged beyond BMS recovery and the pack needs replacement.

Compatible Models

Boomster 2020

Replaces Part Numbers

ICR18650

Technical Specifications

Voltage11.1V
Amp Hours5200mAh
Capacity5200mAh
Rate57.72Wh
Net Weight280g /9.88 oz
Gross Weight430g /15.17 oz
Approximate Weight430g /15.17 oz
Dimension 198.00 x 36.80 x 25.50mm

Product Highlights

  • Brand: Teufel
  • 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 Boomster 2020 plays fine for a while then Bluetooth keeps cutting out at higher volumes — is this the battery?

Yes, and the cause is voltage sag under combined load. At high volume, the amplifier and Bluetooth radio both draw current simultaneously, and an aged or degraded 11.1V pack can't sustain the voltage both subsystems need. The Bluetooth radio loses its supply voltage first and drops the connection, even though the amplifier keeps running at reduced output. Fit a fresh 5200mAh pack and confirm the resting pack voltage reads at least 12.4V off the charger before testing again.

My Boomster 2020 battery drains noticeably faster than it did a year ago even though I charge it every day — what's happening?

Charging it every day is the problem. Constant shallow top-off cycles — plugging in at 60–70% without ever running the pack down — cause Li-ion capacity fade faster than deep cycling does. The fuel gauge also drifts, so the percentage shown stops reflecting actual charge remaining. Run the speaker down below 20% at least once a month before recharging to slow the fade and recalibrate the gauge.

The Boomster 2020 gets noticeably warm on the side during long play sessions — is that the battery overheating?

Heat comes from two sources stacked in a compact housing: the Class D amplifier generates heat under sustained load, and the Li-ion cells generate heat as they discharge. In the Boomster 2020's fabric-covered enclosure there's limited airflow, so both heat sources accumulate. Warm to the touch is normal; hot enough to be uncomfortable is not. If the speaker reaches that point, it typically means the amplifier is working harder than it should due to voltage sag from a degraded pack — replace the 11.1V cell and the thermal load drops back to normal operating range.

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