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BL-T39 LG G7 ThinQ Replacement Battery 3.85V 2900mAh

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New arrival
From $23.99 USD $29.99
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Fits LG G7 ThinQ and replaces OEM battery BL-T39 and EAC63878401.
Delivers 3.85V at 2900mAh—enough capacity to power the Snapdragon processor and display between full charge cycles.
Connector slides into the factory slot with standard LG phone battery orientation and locking tab.
We ran the cell through a full discharge cycle on the G7 motherboard; the BMS accepted the charge handshake without fault codes.
On first use after installation, disable fast charging for one complete discharge-charge cycle so the fuel gauge IC recalibrates against this 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

3.85V

Amp

2900mAh

LG G7 ThinQ — 3.85V Li-Polymer Replacement Battery (BL-T39)

This is a 3.85V, 2900mAh Li-Polymer replacement battery for the LG G7 ThinQ smartphone. It replaces OEM part BL-T39 (also listed as EAC63878401) and fits the G7 ThinQ, G7 ThinQ LTE-A, LMG710AWMH, and the Judy platform variants. Install this when the original cell no longer holds a charge or causes unexpected shutdowns.

  • G7 ThinQ platform fit: The G7 ThinQ, G7 ThinQ LTE-A, and LMG710AWMH variants all share the same battery bay geometry, connector pinout, and BMS handshake protocol — one cell design covers the full lineup without modification.
  • Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the G7 ThinQ platform. The BMS accepted the cell without fault flags, charge termination triggered correctly at 4.35V, and the fuel gauge IC tracked state-of-charge without erratic jumps after one full calibration cycle.
  • First-cycle fast charge tip: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current fast charging pushes into an uncalibrated cell.

Why the G7 ThinQ reports wrong battery percentage after a cell swap

The G7 ThinQ uses a coulomb-counting fuel gauge IC that builds its state-of-charge model against the original cell's discharge curve. Swap the cell, and that model no longer matches the new cell's chemistry profile. The IC keeps referencing its old calibration data, so it reports inaccurate percentages — often reading high and then dropping fast. One complete discharge down to automatic cutoff followed by a full charge to 100% forces the IC to rewrite its reference curve against the new cell.

Sudden shutdown at 20–30% remaining on the G7 ThinQ

This is a voltage cliff failure, not a capacity failure. Under high instantaneous load — modem transmitting, display at full brightness, GPS active — the cell voltage sags below the BMS cutoff threshold even though the fuel gauge still shows charge remaining. An aged or weakened cell cannot sustain voltage under that combined draw. If this happens on a new replacement cell, run the fuel gauge recalibration cycle first. If shutdowns persist after calibration, check that the connector is fully seated — a partially connected cell increases internal resistance and accelerates voltage sag under load, triggering cutoff earlier.

Compatible Models

G7 ThinQ LMG710AWMH G7 ThinQ LTE-A Judy LMG710EMW G7 ThinQ Dual SIM G7 ThinQ Dual SIM TD-LTE LMG710EAW G7+ ThinQ G7 Plus ThinQ G7+ ThinQ Dual SIM G7+ ThinQ Dual SIM TD-LTE G7 Plus ThinQ Dual SIM G7 Plus ThinQ Dual SIM TD-LTE G710VMX LMG710ULM LMG710TM LMG710VM G710N LMG710PM LMG710EM G710EM K40 2019 L423DL L423DL Solo LMX420QM6 X420QN LMX420QN X420QM LMX420QM X420TM LMX420TM LMX420AS8 Xpression Plus 2 LMX420MM LMX420AS LMX420N LMX420HM LMX420BMW K12+ 2019 LMX420EM LMX420EMW LM-G710V Q7+ LM-Q610TA LM-G710TM Phoenix 5 LM-K300MM LM-K300AM LM-K300TM LM-X320APM Arena 2 X320AP X320Q L322DL Journey LMX320AM8 X320TA LMX320TA Aristo 4+ Aristo 4 Plus X320AA LMX320AA Prime 2 LMX320CM Escape Plu Escape Plus LTE X320CM LMX320QM K30 2019 X320QM LMX220N X2 2019 X220N LMQ850QMD G7 Fit Q850QMD Q850EA LMQ850EA Q850EAW LMQ850EAW LMQ850QM LMQ850QM5 LMQ850QM6 Q925L Q9 Q925S LMQ850EM LMQ850EMW

Replaces Part Numbers

BL-T39 EAC63878401

Technical Specifications

Voltage3.85V
Amp Hours2900mAh
Capacity2900mAh
Rate11.17Wh
Net Weight42g /1.48 oz
Gross Weight77g /2.72 oz
Approximate Weight77g /2.72 oz
Dimension 87.60 x 39.05 x 4.90mm

Product Highlights

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

Frequently Asked Questions

My G7 ThinQ won't turn on after the replacement battery sat in a drawer for a few months — is it dead?

Likely not dead, but the BMS has locked out below 2.5V per cell after deep discharge in storage. Plug the phone into a wall charger — not a PC port — and leave it for 20–30 minutes without pressing the power button. The charge IC will trickle current into the cell to bring it back above the BMS recovery threshold. Once the charging indicator appears on screen, a normal charge cycle will restore the cell fully.

USB fast charging stopped working after I installed the replacement battery — what's wrong?

On the first cycle after a cell swap, the G7 ThinQ's USB-PD and Qualcomm Quick Charge handshake can fail to negotiate because the BMS presents unfamiliar impedance characteristics to the charge IC. Run one full standard-rate charge cycle first. After that cycle completes and the fuel gauge IC has a baseline reading, plug back into a fast charger — the protocol negotiation typically succeeds from the second cycle onward. If fast charging still won't activate, try a different QC-certified cable, as the handshake is sensitive to cable resistance at higher current.

The battery percentage on my G7 ThinQ keeps jumping around erratically — 60%, then 45%, then back to 55% within minutes.

This is the fuel gauge IC recalibrating against a new cell it has no reference data for. The coulomb counter's stored discharge model was built on the old cell and is now misreading the new one's voltage-to-capacity curve. Discharge the phone fully until it shuts itself off, then charge uninterrupted to 100% without unplugging early. That single full cycle gives the IC enough data to rewrite its model, and percentage reporting stabilises from that point.

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