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ZTE Axon 40 Ultra Li3949T44P8h806459 4900mAh Battery

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Fits ZTE Axon 40 Ultra, Axon 40 Ultra 5G, and A2023P; replaces OEM Li3949T44P8h806459.
3.89V and 4900mAh rating sustains the modem, display, and processor through a full workday.
Connector slides onto the proprietary ZTE contact pad; orientation keyed by the notch on left edge.
We ran full discharge cycles on bench; the BMS accepted standard USB-PD without throttling on cycle two.
On first charge after installation, disable fast charging for one complete discharge-charge cycle to let the fuel gauge IC recalibrate against the new cell's discharge curve.
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

3.89V

Amp

4900mAh

ZTE Axon 40 Ultra — 3.89V Li-Polymer Replacement Battery (Li3949T44P8h806459)

This is a 4900mAh lithium-polymer replacement battery for the ZTE Axon 40 Ultra and Axon 40 Ultra 5G (A2023P, A2023PH). It runs at 3.89V nominal and delivers 19.06Wh of stored energy. It replaces the original OEM cell when the factory battery has degraded and no longer holds adequate charge.

  • Axon 40 Ultra platform fit: The A2023P and A2023PH share the same internal chassis, connector pinout, and BMS handshake protocol — one cell fits both. The flex connector and NTC thermistor line up without modification.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the Axon 40 Ultra platform and confirmed the BMS accepted the cell, reported state-of-charge without error flags, and held voltage through full-load screen and modem draw.
  • First-cycle fast charge calibration: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Why the Axon 40 Ultra reports wrong battery percentage after a cell swap

The fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual chemistry. The IC reads voltage and estimates charge based on the old model, so the percentage can read 20% higher or lower than reality. One full discharge to automatic shutdown followed by a full charge to 100% forces the IC to rewrite its calibration table against the new cell. After that cycle, percentage reporting typically stabilises within 2–3%.

Sudden shutdown at 20–30% remaining on the replacement cell

This happens when the fuel gauge IC is still using the old cell's voltage-to-capacity curve. The new cell hits its minimum sustain voltage under modem or display load before the IC expects it — the system shuts down to protect the cell even though the reported percentage looks safe. It is not a fault with the replacement cell. Complete one full discharge-charge cycle without fast charging, let the IC recalibrate, and the cutoff point will move back to the correct low-voltage threshold near 3.4V per cell.

Compatible Models

Axon 40 Ultra Axon 40 Ultra 5G A2023P A2023PH

Replaces Part Numbers

Li3949T44P8h806459

Technical Specifications

Voltage3.89V
Amp Hours4900mAh
Capacity4900mAh
Rate19.06Wh
Net Weight68g /2.40 oz
Gross Weight118g /4.16 oz
Approximate Weight118g /4.16 oz
Dimension 79.00 x 64.00 x 5.90mm

Product Highlights

  • Brand: ZTE
  • 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 phone won't turn on at all after sitting in a drawer for months — is the replacement battery dead too?

A cell that sat discharged for an extended period can drop below 2.5V, which triggers BMS lockout to prevent further discharge damage. The BMS will refuse to pass current to the board until the cell is trickle-charged back above that threshold. Plug into a wall charger — not a computer USB port — and leave it for 20–30 minutes without attempting to power on. If the charge LED does not appear after that, try a different cable and confirm the charger outputs at least 5V 1A.

Fast charging stopped working on the first charge after I installed the replacement battery — was it wired wrong?

Fast charge failing on the first cycle after a cell swap is a known USB-PD and proprietary protocol behaviour, not a wiring fault. The charge IC runs a negotiation handshake with the charger, and some firmware builds default to standard 5V charging on the first cycle after the BMS detects a new cell. Complete one full standard charge to 100%, then disconnect and reconnect the charger — fast charging typically resumes from the second cycle onward once the BMS marks the cell as initialised.

The battery percentage jumps around erratically — it drops from 60% to 34% in minutes, then climbs back up without charging.

Erratic percentage jumps are a fuel gauge IC recalibration symptom, not a defective cell. The coulomb counter accumulated drift on the old cell and is now applying that skewed model to the new one, producing readings that swing well outside actual state-of-charge. Run the phone down to automatic shutdown — do not force power-off — then charge uninterrupted to 100% with fast charging disabled. That full discharge-charge cycle resets the IC's reference endpoints and the percentage should stabilise within two to three cycles.

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ZTE Axon 40 Ultra Replacement Battery, 3.89V, 4900mAh, Li-Polymer 1

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