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Bambook SD928+ E-Reader Replacement Battery 3.7V 1300mAh

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From $23.99 USD $29.99
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Fits Bambook SD928+ e-reader; replaces OEM battery MLP454261.
3.7V, 1300mAh lithium-polymer cell delivers adequate capacity for multi-week reading between charges on this e-ink device.
Connector plugs directly into SD928+ battery slot; polarization prevents reverse insertion and secures without adhesive tabs.
We bench tested this cell on the SD928+ mainboard — BMS engaged at 3.7V, no early cutoff, discharge curve stable across full discharge cycle.
After installation, charge via USB for one complete cycle before reading — SD928+ firmware needs a full charge to recalibrate battery percentage display after cell swap.
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.

Disclaimer

⚠️ 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

3.7V

Amp

1300mAh

Bambook SD928+ — 3.7V Li-Polymer Replacement Battery (MLP454261)

This 3.7V, 1300mAh lithium-polymer battery replaces the MLP454261 cell in the Bambook SD928+ e-reader. It restores power to the e-ink display and onboard processor after the original cell degrades or fails to hold charge. Dimensions are 63.00 × 41.70 × 4.70 mm — confirm against your existing cell before fitting.

  • SD928+ fit: The SD928+ uses a compact LiPo cell on a dedicated power rail that drives the e-ink controller and CPU. This cell matches the connector pinout and BMS voltage thresholds the SD928+ firmware expects — no modifications needed.
  • Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the bench. The BMS responded correctly at low-voltage cutoff and held stable voltage through e-ink refresh draws without dropping into protection mode.
  • Post-swap charge cycle: After fitting this cell, connect via USB and run one full charge before powering on. The SD928+ firmware recalibrates its battery percentage display from a full-charge baseline — skipping this step causes the indicator to report inaccurate levels.

Why the SD928+ shows low battery immediately after a new cell is installed

LiPo cells ship in storage mode — typically between 3.6V and 3.85V — to reduce degradation during transit. The SD928+ firmware reads this as a partially depleted cell and flags a low-battery warning. The cell is not faulty. Connect the device to USB power and allow it to charge fully before first boot. Once it reaches 4.2V, the firmware will display an accurate percentage.

Page turns slowing down or freezing after a battery swap

E-ink displays require a voltage spike to refresh the panel — if the cell voltage sags below approximately 3.5V mid-draw, the controller throttles refresh speed or stalls entirely. This happens most often if the new cell was not fully charged before use. A full charge cycle resolves it. If sluggishness continues after charging, check that the battery connector is seated flat — a partial connection causes intermittent voltage drops under refresh load.

Compatible Models

SD928+

Replaces Part Numbers

MLP454261

Technical Specifications

Voltage3.7V
Amp Hours1300mAh
Capacity1300mAh
Rate4.81Wh
Net Weight27.8g /0.98 oz
Gross Weight53g /1.87 oz
Approximate Weight53g /1.87 oz
Dimension 63.00 x 41.70 x 4.70 mm

Product Highlights

  • Brand: Bambook
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Bambook SD928+ won't turn on at all after fitting the new battery — is the cell dead?

Almost certainly not. LiPo cells ship at storage voltage, which can sit below the minimum boot threshold the SD928+ needs to start. Connect it to a USB charger and leave it for 10–15 minutes before pressing the power button — the device will not boot from a depleted starting point. Once the cell climbs above 3.7V, the device should start normally.

The battery percentage on my SD928+ is jumping around — it reads 80%, then drops to 20% a few minutes later.

This is firmware recalibration. The SD928+ estimates charge level against a baseline it builds from the previous cell — when a new cell goes in, those reference points no longer match. Run two full charge and discharge cycles without interruption. The firmware recalculates its fuel gauge curve against the new cell's actual capacity, and the percentage readout stabilises after that.

The SD928+ drains noticeably faster when WiFi sync is turned on — is something wrong with the replacement cell?

Nothing is wrong. WiFi draw on an e-reader is significantly higher than e-ink display refresh alone — the radio pulls a sustained current the cell has to supply on top of normal operation. This is expected behaviour, not a cell defect. Turn WiFi off between manual syncs if you want the charge to last longer between top-ups; the cell capacity at 1300mAh is unchanged from the original specification.

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