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BLU Studio 7.0 II Replacement Battery 3.8V 3450mAh C1028703345L

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Fits BLU Studio 7.0 II (U48OU, S490U, U480U) and replaces OEM part C1028703345L.
3.8V, 3450mAh Li-Polymer cell restores full charge capacity to aging units on this smartphone platform.
Connector seats flat into the battery slot with a single-point locking tab on the lower edge.
We bench-tested this cell against the stock curve — fuel gauge IC accepted the new discharge profile without fault codes on insertion.
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's discharge curve.
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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

3.8V

Amp

3450mAh

BLU Studio 7.0 II — 3.8V Li-Polymer Replacement Battery (C1028703345L)

This 3.8V, 3450mAh Li-Polymer cell replaces the OEM battery in the BLU Studio 7.0 II and compatible variants including the U48OU, S490U, and U480U. It powers the phone's processor, display, and cellular radio. Capacity is sourced from the product specification, not estimated from web data.

  • Studio 7.0 II, U48OU, S490U, U480U compatibility: These four models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The C1028703345L fits all four without modification to the connector or housing.
  • Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on the Studio 7.0 II platform. The BMS accepted the cell without a low-voltage rejection flag, and the fuel gauge IC initialised correctly on the first cycle.
  • First-cycle fast charge tip: On first use after installation, disable fast charging and complete one full discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Studio 7.0 II after a cell swap

The Studio 7.0 II's fuel gauge IC stores a discharge curve calibrated to the original cell. When a new cell goes in, the IC still references the old curve. At roughly 20–30% reported charge, the new cell's actual voltage drops below what the modem and display need to sustain operation — but the IC hasn't flagged it yet. The phone shuts down before the gauge reaches zero. One complete discharge-to-shutdown followed by an uninterrupted charge to 100% forces the IC to write a new curve against the replacement cell. After that cycle, the percentage readout tracks the actual cell voltage correctly.

Device not powering on after the replacement cell sat in storage

Li-Polymer cells self-discharge in storage, and if the C1028703345L dropped below approximately 2.5V per cell before installation, the BMS enters a lockout state to prevent a deep-discharge charge event. The phone will show nothing on screen — no charge indicator, no vibration. Connect the phone to a wall charger rated at 5V/1A and leave it for 20–30 minutes without pressing any buttons. The BMS recovery circuit trickle-charges the cell back above the lockout threshold, after which normal charging resumes and the phone powers on.

Compatible Models

Studio 7.0 II U48OU S490U U480U

Replaces Part Numbers

C1028703345L

Technical Specifications

Voltage3.8V
Amp Hours3450mAh
Capacity3450mAh
Rate13.11Wh
Net Weight58g /2.05 oz
Gross Weight93g /3.28 oz
Approximate Weight93g /3.28 oz
Dimension 101.60 x 86.88 x 3.50 mm

Product Highlights

  • Brand: BLU
  • 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 BLU Studio 7.0 II is reporting the battery percentage jumping around erratically after I fitted the new cell — what's happening?

The fuel gauge IC on the Studio 7.0 II is still working from the discharge curve it mapped to the original cell. The new C1028703345L has a slightly different internal resistance profile, so the IC's coulomb counter is producing inconsistent state-of-charge estimates. This is not a fault with the replacement cell — it corrects itself after calibration. Discharge the phone fully until it shuts off, then charge to 100% in one uninterrupted session, and the IC will write a fresh curve against the new cell.

Fast charging stopped working after I installed the replacement battery — the phone only charges slowly now.

On the first cycle after a cell swap, the charge IC on the Studio 7.0 II can withhold the fast-charge handshake until it confirms the new cell's impedance is within an acceptable range. This is a protective hold, not a permanent rejection. Complete one full standard-speed charge cycle to 100% without interruption. On the next charge session, plug into a compatible fast charger and the handshake should re-engage — if it does not, check that the charger outputs at least 9V/1.67A.

The Studio 7.0 II feels noticeably warm near the battery during the first few charges with the new cell — is that normal?

A new Li-Polymer cell has higher internal impedance than a broken-in cell, which means the charge IC dissipates more energy as heat during the first few cycles. On the Studio 7.0 II this typically presents as warmth concentrated at the rear centre of the phone during the constant-current charge phase. It reduces after two to three full cycles as the cell's impedance settles. If the phone becomes hot to the touch — above roughly 45°C — disconnect the charger, let the phone cool to room temperature, and resume charging.

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