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Samsung Galaxy S25 5G EB-BS931ABY Replacement Battery 3850mAh

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From $43.99 USD $54.99
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Fits Samsung Galaxy S25 5G with OEM part number EB-BS931ABY replacement.
3.9V, 3850mAh Li-Polymer cell restores full charge capacity to aged devices experiencing shortened runtime between charging cycles.
Connector seats into the S25 5G battery cavity with no mechanical locking tab — slides flush against the phone's internal contact frame.
We bench-tested this pack in an SM-S931B unit; the BMS accepted charge current immediately, fuel gauge IC initialized without fault codes or voltage sag.
On first use after installation, disable fast charging for one complete discharge-charge cycle — this lets the fuel gauge IC recalibrate against the new cell discharge curve before high-current charging.
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

3.9V

Amp

3850mAh

Samsung Galaxy S25 5G — 3.9V Li-Polymer Replacement Battery (EB-BS931ABY)

This is a 3850mAh Li-Polymer replacement battery for the Samsung Galaxy S25 5G. It fits SM-S9310, SM-S931B, SM-S931B/DS, and related variants. Voltage is 3.9V nominal, matching the original cell specification.

  • SM-S931 series compatibility: Every SM-S931 variant shares the same 68.60 × 62.20 × 4.60mm cell footprint, connector pinout, and BMS communication protocol. The fuel gauge IC reads charge state over the same data line across all regional builds — DS (dual-SIM) and single-SIM boards included.
  • Bench tested on actual hardware: We ran this cell on an SM-S931B board and confirmed BMS handshake, charge acceptance from 0% to 100%, and correct voltage reporting at 4.35V full-charge cutoff. The charge IC accepted standard and fast-charge current profiles without fault flags.
  • Fuel gauge recalibration on first use: After installation, disable fast charging in Settings and run one complete discharge-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff, not a capacity fault. Under peak modem load or display brightness, a fresh cell with an uncalibrated fuel gauge IC can sag below the board's minimum voltage threshold before the percentage reaches zero. The phone shuts down to protect the SoC even though the reported percentage looks safe. One full discharge-to-shutdown followed by a complete charge cycle lets the coulomb counter anchor to the real cell curve and eliminates most premature cutoffs.

USB-PD fast charge not accepted on first cycle after swap

On the first charge after a cell replacement, the charge IC sometimes defaults to trickle current while it verifies BMS authentication. This is normal — the charger negotiates voltage and current with the BMS, and until the BMS confirms cell state, it limits input. Plug into a USB-PD charger, wait five minutes, then unplug and reconnect. If fast charging still does not engage after a full standard-current charge cycle, check that the battery connector is fully seated — a partial connection raises contact resistance and the charge IC interprets this as a fault.

Compatible Models

Galaxy S25 5G SM-S9310 SM-S931B SM-S931B/DS SM-S931D SM-S931J SM-S931N SM-S931Q SM-S931U SM-S931U1 SM-S931W SM-S931Z

Replaces Part Numbers

EB-BS931ABY

Technical Specifications

Voltage3.9V
Amp Hours3850mAh
Capacity3850mAh
Rate15.02Wh
Net Weight51g /1.80 oz
Gross Weight76g /2.68 oz
Approximate Weight76g /2.68 oz
Dimension 68.60 x 62.20 x 4.60mm

Product Highlights

  • Brand: Samsung
  • 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 Galaxy S25 5G shuts off at around 25% battery — did I get a faulty replacement cell?

Almost always this is the fuel gauge IC reading from the old cell's discharge curve, not a defective cell. The coulomb counter calibrated itself to your original degraded battery and doesn't yet know where the new cell's voltage cliff sits. Run the phone down until it shuts itself off, then charge it fully in one uninterrupted session at standard speed. That single cycle gives the fuel gauge enough data to reanchor its percentage calculation to the new cell.

The battery percentage on my S25 5G jumps around erratically after I installed this replacement — is the BMS faulty?

The BMS is fine — the fuel gauge IC is recalibrating. After a cell swap, the coulomb counter has no reference for the new cell's internal resistance or discharge curve, so percentage readings can jump 5–10% in either direction under load. This settles after two to three full discharge-charge cycles at standard current. If the jumping continues past three cycles, check that all four connector pins are making clean contact — a dirty or slightly unseated connector causes resistance spikes that the fuel gauge reads as sudden capacity loss.

My S25 5G gets noticeably warm near the battery while charging the new cell — is this normal?

A new high-impedance cell runs warmer on the first few charge cycles than a broken-in cell does. The charge IC pushes current into a cell with slightly higher internal resistance until the cell's electrolyte and electrode surfaces condition. Warmth that fades after three to five charge cycles is expected. If the phone stays hot throughout a full charge and the charge IC does not step down to trickle near 100%, check Settings → Battery → Charging Speed and confirm fast charging is disabled for the first cycle — 25W input into an unconditioned cell generates significantly more heat than standard 15W charging.

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