Sunmi M2 Max Replacement Battery JKLK 3.85V 8400mAh
This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.
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Sunmi M2 Max Replacement Battery JKLK 3.85V 8400mAh - 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
⚠️ 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.
Sunmi M2 Max Replacement Battery JKLK 3.85V 8400mAh - is backordered and will ship as soon as it is back in stock.
Voltage
3.85V
Amp
8400mAh
Sunmi M2 Max — 3.85V Li-Polymer Replacement Battery (JKLK)
This is a 3.85V, 8400mAh lithium-polymer battery for the Sunmi M2 Max commercial Android tablet. It fits the M2 Max and P10010016 model variants. Swap this in when the original cell has degraded and the tablet can no longer hold a full working charge.
- M2 Max and P10010016 compatibility: Both variants use the same battery bay geometry, connector pinout, and charge IC handshake. The JKLK part number is the shared OEM reference across the M2 Max line — no adapter or modification needed.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the M2 Max platform. The BMS accepted the charge IC handshake on first connection, voltage held stable under combined display and WiFi load, and protection thresholds tripped correctly at low-voltage cutoff.
- Fuel gauge recalibration after swap: After installation, run the tablet down to automatic shutoff, then charge uninterrupted to 100% without using the device. This forces the fuel gauge IC to recalibrate against the new cell's actual capacity curve and clears the inaccurate percentage readings that appear immediately after a battery replacement.
Tablet shutting down at 15–25% remaining after battery swap
This happens because the fuel gauge IC is still calibrated to the old cell's voltage curve. The new cell hits a voltage cliff under combined display, WiFi, and background process load — the tablet reads this drop as critically low and shuts down, even though capacity remains. It is not a fault with the replacement cell. Run one full discharge to automatic shutoff followed by an uninterrupted charge to 100%, and the shutdowns will stop. After that cycle, the IC maps the correct low-voltage threshold at approximately 3.5V per cell.
Fast charging not available on the M2 Max after a battery replacement
USB-PD negotiation on the M2 Max requires at least one completed charge cycle before the charge controller steps up to higher wattage with a new cell. On the first charge after installation, the controller runs a conservative profile while it characterises the new cell's internal resistance. Plug in, let the tablet charge fully without interruption, and fast charge will be available from the second charge cycle onward. If it still does not appear, confirm the charger is the original Sunmi adapter — third-party chargers often fail USB-PD negotiation entirely.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Sunmi
- 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
The Sunmi M2 Max is showing 60% battery but just switched itself off — is the new cell faulty?
The cell is almost certainly fine. The fuel gauge IC was calibrated to the old battery and its voltage curve does not match the new cell — so the tablet reads a sharp voltage drop under load and shuts down before the real charge is exhausted. Run the tablet all the way down to automatic shutoff, then charge it uninterrupted to 100%. After that single full cycle, the IC recalibrates and the premature shutdowns stop.
The M2 Max battery percentage is jumping around — it reads 80%, drops to 55% in ten minutes, then jumps back up. What's causing this?
Fuel gauge drift after a battery swap. The charge IC is still using the old cell's discharge curve as its reference, so percentage readings are unreliable until the new cell is properly mapped. Do one complete discharge to automatic shutoff followed by a full uninterrupted charge to 100%. That single calibration cycle gives the IC an accurate low-point and high-point reference, and the erratic jumps resolve. Do not interrupt the charge cycle partway — a partial charge will not recalibrate the gauge.
The M2 Max feels warm near the charging port while charging the new battery — should I be concerned?
Mild warmth during the first few charge cycles is normal. The charge IC runs a slow characterisation profile on a new cell to measure internal resistance before it allows higher charge rates, and that process generates low-level heat. If the tablet is warm but not hot to the touch and cools down once charging completes, nothing is wrong. If the back becomes uncomfortably hot or charging stops and restarts repeatedly, check that the charger output matches the Sunmi OEM spec — the M2 Max charge controller will throttle or cut off if input voltage is out of range.
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