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T-Mobile G2 Replacement Battery BA S450 3.7V 1500mAh

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From $22.99 USD $28.99
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Fits T-Mobile G2 smartphone; replaces OEM battery part numbers BA S450, 35H00140-00M, and 35H00140-01M.
3.7V at 1500mAh capacity delivers stable voltage across calling, messaging, and app use on the G2.
Connector slides into the battery slot with a locking tab; orient the gold contacts toward the device terminals.
We tested the new BMS on a G2 unit; fuel gauge IC stabilized after one full discharge-charge cycle.
On first use after installation, disable fast charging for one complete discharge-charge cycle so the coulomb counter recalibrates against the new cell 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

3.7V

Amp

1500mAh

T-Mobile G2 — 3.7V Li-ion Replacement Battery (BA S450)

This is a 3.7V, 1500mAh Li-ion replacement battery for the T-Mobile G2 smartphone. It fits the G2 directly and uses OEM part numbers BA S450, 35H00140-00M, and 35H00140-01M. Replace this battery when the original cell no longer holds adequate charge or fails to power the device.

  • T-Mobile G2 fit: The G2 uses a dedicated battery bay sized for this 65 x 43 x 5mm cell. The connector and BMS handshake are matched to the phone's charge IC — no adapter or modification needed.
  • Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the G2 platform. The BMS communicated correctly with the phone's fuel gauge IC, and charge termination triggered at the correct cutoff voltage without fault flags.
  • Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the T-Mobile G2 after a cell swap

The G2's fuel gauge IC holds a discharge curve learned from the original cell. A new cell has a different internal resistance profile, so the gauge miscalculates remaining capacity. Under modem or screen load, the cell voltage drops faster than the gauge predicts and the phone shuts off to protect the BMS — even though the reported percentage looked safe. One full discharge-charge cycle forces the coulomb counter to relearn the new cell's voltage-to-capacity curve and eliminates premature shutdowns.

Phone not powering on after the replacement battery sat in storage

Li-ion cells self-discharge over time in storage. If the cell drops below approximately 2.5V, the BMS enters lockout mode and the phone will not power on — even with a charger connected. Connect the phone to a wall charger and leave it for 20–30 minutes without pressing the power button. The charge IC needs time to trickle-charge the cell back above the BMS wake threshold before a normal boot is possible.

Compatible Models

G2

Replaces Part Numbers

BA S450 35H00140-00M 35H00140-01M

Technical Specifications

Voltage3.7V
Amp Hours1500mAh
Capacity1500mAh
Rate5.55Wh
Net Weight30g /1.06 oz
Gross Weight55g /1.94 oz
Approximate Weight55g /1.94 oz
Dimension 65.00 x 43.00 x 5.00mm

Product Highlights

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

Frequently Asked Questions

My T-Mobile G2 shows 25% battery and then shuts off without warning — is this the new cell?

Yes. The fuel gauge IC on the G2 is calibrated to the original cell's discharge curve. A replacement cell has a different internal resistance, so the gauge underestimates how fast voltage drops under load — the phone cuts power before the reported percentage reaches zero. Run one full discharge-to-charge cycle without interruption and the coulomb counter will relearn the new cell's curve. Shutdowns at 20–30% typically stop after that single calibration cycle.

The G2 percentage keeps jumping around erratically after I put this battery in — what's happening?

Erratic percentage jumps are a fuel gauge IC recalibration issue, not a faulty cell. The G2's coulomb counter is comparing the new cell's voltage readings against an old learned curve, so it oscillates between estimates as the mismatch becomes apparent under varying loads. Do not top up or partially charge during this period. Let the battery drain to auto-shutdown, then charge to 100% in a single uninterrupted session — the gauge IC will lock onto the correct curve after that cycle.

Fast charging stopped working on the G2 after I replaced the battery — the phone just slow-charges now.

On the first cycle after a cell swap, the G2's charge IC defaults to a conservative current profile because it has no BMS history for the new cell. This is expected behaviour — the phone is protecting an uncalibrated cell from high-current input. Complete one full slow charge to 100%, then discharge to auto-shutdown. After that cycle, the charge IC recognises the cell's impedance profile and re-enables its higher charge current on subsequent sessions.

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