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Neffos C9 Max Compatible Battery NBL-40A2950 3.85V 2850mAh

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From $26.99 USD $33.99
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Fits Neffos C9 Max and TP7062 models, replacing OEM part NBL-40A2950.
3.85V, 2850mAh Li-Polymer cell delivers rated capacity for full-day operation on this handset.
Connector slides onto the stock pad with a single locking tab on the left side.
We ran a full discharge cycle on the bench — the BMS accepted USB input without protocol errors on second charge.
On first use after installation, disable fast charging for one complete discharge-charge cycle to let the fuel gauge IC recalibrate against the new cell 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.

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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.

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🔹 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

2850mAh

Neffos C9 Max / TP7062 — 3.85V Li-Polymer Replacement Battery (NBL-40A2950)

This is a 3.85V Li-Polymer cell rated at 2850mAh (10.97Wh), built to the NBL-40A2950 specification. It fits the Neffos C9 Max (TP7062) and replaces an original cell that no longer holds a charge or shuts down unexpectedly. Dimensions are 77.90 × 59.20 × 4.00mm — verify against your current cell before fitting.

  • C9 Max and TP7062 fit: Both models use the same battery bay, connector pinout, and BMS communication protocol. The NBL-40A2950 part number covers both variants — same voltage rail, same cell footprint, same charge IC handshake.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on a test unit. The BMS accepted a standard 5V/2A charge without error flags, and protection cutoffs triggered correctly at both ends of the voltage window.
  • Fuel gauge recalibration on first install: On first use after fitting, disable fast charging and complete one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before fast charging pushes higher current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Neffos C9 Max after a cell swap

This happens when the fuel gauge IC is still reading the old cell's discharge curve. The new cell hits a voltage cliff under modem or display load — the phone sees the voltage drop and shuts off before the reported percentage reaches zero. It is not a fault with the replacement cell. One complete discharge-charge cycle at standard current recalibrates the coulomb counter. After that cycle, shutdowns below 30% typically stop.

OS reporting a wrong or jumping battery percentage after replacement

The fuel gauge IC on the C9 Max stores a learned discharge model for the original cell. A new cell with a different internal resistance profile will cause the reported percentage to jump or stall — commonly around 50% or on the way down from 80%. This is a calibration gap, not a defective cell. Force a full discharge until the phone powers off on its own, then charge uninterrupted to 100%. One or two cycles like this resets the IC's tracking to the new cell's actual curve.

Compatible Models

C9 Max TP7062

Replaces Part Numbers

NBL-40A2950

Technical Specifications

Voltage3.85V
Amp Hours2850mAh
Capacity2850mAh
Rate10.97Wh
Net Weight44.2g /1.56 oz
Gross Weight94.2g /3.32 oz
Approximate Weight94.2g /3.32 oz
Dimension 77.90 x 59.20 x 4.00mm

Product Highlights

  • Brand: Neffos
  • 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

My Neffos C9 Max won't power 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 below 2.5V per cell due to deep discharge in storage. Connect the phone to a 5V/1A charger and leave it for 20–30 minutes without pressing the power button — the charge IC needs to trickle current into the cell before the BMS will unlock and allow normal charging to start. If the charge LED comes on within that window, the cell is recovering. If nothing happens after 45 minutes on charge, check that the connector is fully seated.

Fast charging stopped working on the C9 Max after I fitted the replacement — it only charges slowly now.

On the first cycle after a cell swap, the phone's charge IC sometimes falls back to standard 5V/1A because the USB-PD or proprietary fast-charge handshake hasn't been accepted by the new BMS yet. Complete one full standard-rate charge to 100%, then disconnect and let the phone cool to room temperature. Reconnect to your fast charger — the handshake typically re-establishes on the second cycle. If fast charging still does not activate after two full cycles, try a different fast-charge cable, as connector resistance can block the initial negotiation.

The Neffos C9 Max gets noticeably warm near the battery area during the first few charges with the new cell — is that normal?

A new Li-Polymer cell has higher internal impedance than a well-cycled cell, so the charge IC works harder to push current in during the first few cycles, which produces more heat. This is expected and reduces after three to five full charge cycles as the cell's impedance settles. Keep the phone out of a case during these initial charges to let heat dissipate. If the back becomes uncomfortably hot to hold — above roughly 45°C — disconnect and let it cool before continuing.

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