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Asus ZenFone 3s Max C11P1614 Replacement Battery 3.85V 5000mAh

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From $26.99 USD $33.99
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Fits Asus ZenFone 3s Max and ZC521TL models, replacing OEM part C11P1614.
3.85V nominal, 5000mAh capacity sustains the large display and modem without mid-day recharge.
Connector slides straight into the battery slot with no locking tab — orientation is keyed.
We charged from dead and saw normal BMS handshake; the fuel gauge IC settled after one full cycle.
On first use after installation, disable fast charging for one complete discharge-charge cycle so the coulomb counter recalibrates against the new cell's discharge curve.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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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

3.85V

Amp

5000mAh

Asus ZenFone 3s Max — 3.85V Li-Polymer Replacement Battery (C11P1614)

This 3.85V, 5000mAh Li-Polymer cell replaces the original C11P1614 battery in the Asus ZenFone 3s Max. It fits the ZC521TL, ZenFone 3s Max Dual SIM TD-LTE IN, and ZenFone Pegasus 3S variants. Rated at 19.25Wh, it matches the factory spec so the phone's charge IC operates within its intended parameters.

  • ZC521TL and Pegasus 3S fitment: These variants share the same 3.85V power rail, connector pinout, and BMS handshake as the standard ZenFone 3s Max, so one cell covers all listed models without adapter or modification.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on a ZC521TL unit. The BMS accepted the charge IC handshake on the first cycle, held voltage through heavy screen-on load, and tripped no protection cutoffs.
  • Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after installation. The ZenFone 3s Max uses a coulomb counter that calibrated its curve against the old cell — running one slow cycle gives the fuel gauge IC accurate endpoints before fast charge current is applied.

Why the ZenFone 3s Max reports wrong battery percentage after a cell swap

The ZenFone 3s Max uses a coulomb counter that tracks charge flow relative to a stored discharge curve from the original cell. When a new cell goes in, the counter still references that old curve, so percentages drift from the actual state of charge. The gauge does not auto-reset — it needs at least one full cycle from 100% charge down to automatic shutdown and back to full. After that single cycle, the reported percentage aligns closely with real cell voltage across the 3.85V nominal range.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC has not yet mapped the new cell's voltage cliff. Li-Polymer cells drop voltage steeply below roughly 3.5V per cell, and the modem or display load can pull the cell below that threshold faster than the uncalibrated counter expects. The phone interprets this as a hard undervoltage event and cuts power before the reported percentage reaches zero. Run one full discharge cycle to let the gauge learn the new cliff point — after calibration, shutdowns below 15% stop occurring.

Compatible Models

ZenFone 3s Max ZenFone 3s Max Dual SIM TD-LTE IN ZC521TL ZenFone Pegasus 3S ZenFone Pegasus 3S Dual SIM TD-LTE

Replaces Part Numbers

C11P1614

Technical Specifications

Voltage3.85V
Amp Hours5000mAh
Capacity5000mAh
Rate19.25Wh
Net Weight64.8g /2.29 oz
Gross Weight100g /3.53 oz
Approximate Weight100g /3.53 oz
Dimension 87.20 x 64.52 x 4.70mm

Product Highlights

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

Frequently Asked Questions

The phone won't turn on at all after the replacement battery sat in a drawer for a few months — is the cell dead?

Probably not dead, but the BMS has locked out due to deep discharge. Li-Polymer cells dropped below 2.5V trigger a protection circuit that blocks normal boot. Plug the phone into a wall charger — not a computer USB port — and leave it for 30–45 minutes without pressing the power button. Once the cell recovers above 3.0V, the BMS releases and the phone boots normally.

Fast charging stopped working the first time I charged the replacement — it only trickle charges now.

The ZenFone 3s Max's charge IC runs a handshake on the first cycle with a new cell and may default to trickle rate if it flags any impedance mismatch. This is normal on cycle one with a fresh Li-Polymer cell that has higher internal impedance before conditioning. Let the first charge complete at the slow rate, discharge the phone to around 10%, then charge again — the IC renegotiates at the correct fast-charge current on the second cycle. If fast charging still does not engage, check that the charger outputs at least 5V/2A.

The battery percentage jumps around erratically — it reads 45%, then skips to 60%, then drops back to 38% within minutes.

That erratic jump is the coulomb counter actively recalibrating against the new cell's discharge curve. The stored reference points from the old cell are mismatched to the new chemistry, so the gauge corrects in visible steps rather than smoothly. It is not a fault in the replacement cell. Complete two full discharge-charge cycles — draining to automatic shutdown each time — and the percentage will stabilise because the counter will have mapped at least two accurate endpoints on the C11P1614 curve.

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