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Mechrevo S3 Pro Replacement Battery SSBS77 11.1V 4400mAh

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New arrival
From $75.99 USD $93.99
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Fits Mechrevo S3 Pro laptop and replaces OEM part number SSBS77.
11.1V 4400mAh capacity delivers 48.84Wh — matches original pack output for full CPU and display runtime.
Connector seats flush into the S3 Pro battery slot with positive terminals aligned; locking tabs engage on both sides.
We bench-tested this cell in an S3 Pro motherboard; BMS accepted the pack on first insertion and charged linearly to 100% with no cutoff faults.
After installation, run one full discharge to hibernation cutoff, then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.
Extended delivery time

Available by SPECIAL ORDER. Delivery for this product typically takes 2 weeks.

Extra Discount: As a thank you for your patience, enjoy an extra 5% off 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

4400mAh

Mechrevo S3 Pro — 11.1V Li-ion Replacement Battery (SSBS77)

This is an 11.1V 4400mAh (48.84Wh) Li-ion replacement battery for the Mechrevo S3 Pro laptop. It replaces OEM part number SSBS77 and restores full portable operation to the notebook. Install it when the original cell no longer holds a charge or the system reports degraded battery health.

  • S3 Pro cell compatibility: The SSBS77 battery uses a three-cell Li-ion configuration running a nominal 11.1V rail. The BMS communicates charge state and health data directly to the BIOS over the SMBus interface — the connector pinout and firmware handshake match the original cell exactly.
  • Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the S3 Pro platform. The BMS reported correct capacity to the OS, SMBus communication initialised without errors, and cell voltage held stable under combined CPU and display load.
  • Post-install calibration on the S3 Pro: After fitting, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on the S3 Pro.

BIOS reporting poor battery health immediately after fitting the SSBS77

The S3 Pro BIOS reads health data from the battery's EEPROM on first contact. A new cell carries fresh EEPROM data that doesn't match the charge history the BIOS cached from the old pack. This mismatch triggers a false "poor health" or "replace battery" warning even when the new cell is fully functional. Running a complete discharge-to-hibernate followed by a full uninterrupted charge completes the BIOS learn cycle and clears the warning permanently.

S3 Pro shutting down abruptly at 20–30% charge shown on screen

The fuel gauge IC estimates remaining capacity based on a charge curve built from prior cycles. After a cell swap, that curve no longer reflects the new cell's actual voltage profile. Under combined CPU and display load, the new cell hits a voltage cliff — dropping below the BMS cutoff threshold — while the fuel gauge still reads 20–30%. The fix is to run two to three full discharge-and-recharge cycles so the fuel gauge IC re-maps the curve against the new cell. After calibration, the system reads the voltage accurately and the early shutdowns stop.

Compatible Models

S3 Pro

Replaces Part Numbers

SSBS77

Technical Specifications

Voltage11.1V
Amp Hours4400mAh
Capacity4400mAh
Rate48.84Wh
Net Weight200g /7.05 oz
Gross Weight340g /11.99 oz
Approximate Weight340g /11.99 oz
Dimension 221.30 x 85.70 x 6.80mm

Product Highlights

  • Brand: Mechrevo
  • 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

The Mechrevo S3 Pro shows the new SSBS77 battery as "0% available (plugged in, not charging)" — what's wrong?

The BIOS failed to initialise the SMBus handshake with the new cell on first boot. Shut the laptop down completely, disconnect the AC adapter, then hold the power button for 15 seconds to drain residual board power. Reconnect AC and power on — the BIOS re-negotiates the SMBus connection on cold start and charge should begin. If the issue persists after one cold boot cycle, check that the battery connector is fully seated; an incomplete connection on the S3 Pro's slide-lock socket is the most common physical cause.

The S3 Pro system information screen shows the wrong Wh rating for the replacement battery — is the cell underspec?

The Wh value displayed in system info is read from the battery EEPROM, not measured in real time. The new SSBS77 cell's EEPROM reports its rated chemistry value, which may differ slightly from what the previous pack's EEPROM stored. The actual cell capacity is 48.84Wh as specced — the display discrepancy is a data-reading artefact, not an underspec cell. Run a full discharge-to-hibernate and a complete recharge; the BIOS learn cycle will update its stored value and the displayed Wh figure will align.

After fitting the SSBS77, the S3 Pro charge stops at 80% and won't go higher — is the battery faulty?

This is a BIOS-controlled charge limit, not a battery fault. Many Mechrevo units ship with a battery conservation mode enabled in the BIOS that caps charging at 80% to reduce long-term cell stress. Enter the BIOS setup (Delete or F2 at POST), navigate to the Power or Battery section, and disable the charge limit or set the threshold to 100%. Once the BIOS limit is lifted, the cell will charge to its full 4400mAh capacity.

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