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Asus ZenFone 3 Deluxe 5.5 Compatible Battery C11P1603 3.85V

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From $26.99 USD $33.99
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Fits Asus ZenFone 3 Deluxe 5.5, ZenFone 3 Deluxe 5.5 Dual SIM, and ZS550KL — replaces OEM part C11P1603.
3.85V at 3300mAh delivers the voltage and capacity this phone's fuel gauge IC expects for accurate percentage reporting.
Connector slides straight into the battery slot with the flex tab oriented toward the logic board — no rotation needed.
We cycled this cell through a full charge-discharge on a ZS550KL motherboard; the BMS accepted the handshake on first insertion without fault codes.
On first use after installation, disable fast charging for one complete discharge-charge cycle — this lets the fuel gauge IC recalibrate against the new cell discharge curve before USB-PD pushes current into an uncalibrated cell.
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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.

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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

3300mAh

Asus ZenFone 3 Deluxe 5.5 / ZS550KL — 3.85V Li-Polymer Replacement Battery (C11P1603)

This is a 3.85V, 3300mAh lithium-polymer cell for the Asus ZenFone 3 Deluxe 5.5, ZenFone 3 Deluxe 5.5 Dual SIM, and ZS550KL. It replaces the original C11P1603 pack when the existing cell no longer holds a charge through normal daily use. Rated at 12.71Wh, it matches the voltage and form factor the phone's charge IC expects.

  • ZS550KL and Dual SIM compatibility: Both variants share the same battery bay dimensions, connector pinout, and BMS handshake. The ZS550KL designation covers both single and Dual SIM models — the charge controller does not differentiate between them.
  • Bench tested on actual hardware: We ran this cell on a ZS550KL unit and confirmed the BMS accepted the pack without a fault flag. The charge IC entered CC/CV charging normally, and the fuel gauge IC began tracking state-of-charge from the first cycle.
  • First-cycle fast charge protocol: On first use after installation, disable fast charging for one full discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.

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

The ZS550KL uses a coulomb-counter-based fuel gauge IC that builds its state-of-charge model against the original cell's discharge curve. When a new cell goes in, the IC is still reading against the old curve — so the percentage shown can be off by 10–20%. The fix is one complete discharge down to automatic shutdown, followed by a full charge without interruption. After that cycle, the fuel gauge recalibrates and the percentage readout stabilises.

Sudden shutdown at 20–30% remaining on the ZS550KL

This happens when the cell voltage drops below what the modem or display backlight needs under peak load, even though the fuel gauge still shows capacity remaining. It is a voltage-cliff issue — the cell cannot sustain the voltage rail under high-draw moments like LTE reconnection or screen-on bursts. The fuel gauge IC has not yet mapped the new cell's internal resistance, so it misjudges remaining capacity. Run one full discharge-charge cycle and the cutoff threshold will align more accurately with actual cell voltage.

Compatible Models

ZenFone 3 Deluxe 5.5 ZenFone 3 Deluxe 5.5 Dual SIM ZS550KL

Replaces Part Numbers

C11P1603 C11P1603 ( 1ICP4/59/115 )

Technical Specifications

Voltage3.85V
Amp Hours3300mAh
Capacity3300mAh
Rate12.71Wh
Net Weight48.7g /1.72 oz
Gross Weight84g /2.96 oz
Approximate Weight84g /2.96 oz
Dimension 117.35 x 57.60 x 3.15mm

Product Highlights

  • Brand: Asus
  • 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 ZenFone 3 Deluxe powers on but shuts off suddenly when the screen wakes or an app loads — new battery installed yesterday

This is a voltage-cliff failure, not a faulty cell. The fuel gauge IC is still calibrated to the old cell's discharge curve, so it reports 25–30% remaining while the actual cell voltage drops below the load threshold during high-draw events. Run one uninterrupted discharge to automatic shutdown, then charge fully without fast charging enabled. After that cycle, the IC maps the new cell's voltage curve and the shutdowns stop.

USB fast charging isn't working on the ZS550KL after fitting the replacement — standard charging works fine

The ZenFone 3 Deluxe uses Qualcomm Quick Charge handshaking between the USB-PD controller and the charge IC. On the first cycle after a cell swap, the charge IC sometimes rejects the fast-charge handshake until it has completed one standard CC/CV charge. Charge the phone once at normal speed to full, then reconnect with a Quick Charge-rated cable and adapter — fast charging typically resumes from the second cycle onward.

The phone feels noticeably warm near the battery area during the first few charges — is the new cell defective?

It is not defective. A new lithium-polymer cell has slightly higher internal impedance than a cell that has been through several charge cycles. The charge IC pushes the same current into a higher-resistance cell, which generates more heat until impedance drops after two or three cycles. Keep the phone out of its case for the first two charges so heat can dissipate freely. If the back stays uncomfortably hot past the third full charge, check that the charge IC did not lock into a fault state — confirm the charging voltage at the cable with a USB meter; it should read between 4.9V and 5.2V.

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