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BN3A Redmi Go Compatible Battery 3.85V 2900mAh Li-Polymer

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From $24.99 USD $30.99
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Replaces Xiaomi Redmi Go original BN3A battery across M1903C3GH and M1903C3GG models.
Delivers 3.85V at 2900mAh—matches OEM capacity to restore full operational time on calls, messaging, and apps.
Single-cell Li-Polymer pack connects via vertical JST connector at top edge; alignment tab prevents reverse insertion.
We bench-tested this cell on a Go unit; fuel gauge IC showed flat voltage response through 80% discharge before stabilizing recovery curve.
On first use, disable fast charging for one complete discharge-charge cycle—lets the coulomb counter recalibrate against the new cell's discharge curve before high-current charging.
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.

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

Redmi Go (M1903C3GH / M1903C3GG) — 3.85V Li-Polymer Replacement Battery (BN3A)

This is a 3.85V, 2900mAh (11.17Wh) Li-Polymer replacement battery for the Redmi Go smartphone. It fits the M1903C3GH and M1903C3GG variants and replaces OEM part BN3A. Install it when the original cell has degraded, won't hold charge, or causes unexpected shutdowns.

  • Redmi Go variant compatibility: The M1903C3GH and M1903C3GG share the same battery bay dimensions, connector pinout, and BMS handshake protocol — both accept the BN3A cell without modification. The 3.85V nominal rail matches the charge IC on both boards.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Redmi Go unit. The BMS accepted charge from both standard 5V/1A and 5V/2A inputs without fault flags. Voltage held stable under simultaneous screen-on and LTE load.
  • Fuel gauge recalibration after swap: 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's discharge curve before high-current charging is applied to an uncalibrated cell.

Why the Redmi Go reports wrong battery percentage after a cell swap

The Redmi Go uses a coulomb counter IC that builds its charge map from cycles on the original cell. When a new cell goes in, that map no longer matches the actual discharge curve. The phone reads percentage from a stale reference table, so it can show 40% and then jump to 15% without warning. One full discharge to automatic shutdown, followed by a full charge to 100%, resets the counter and aligns the gauge to the new cell.

Sudden shutdown at 20–30% charge remaining

This is a voltage cliff issue, not a capacity problem. Under combined modem and display load, cell voltage drops sharply at lower states of charge — faster than the fuel gauge IC anticipates. When voltage sags below the shutdown threshold (typically around 3.4V), the phone cuts power even though the gauge still shows 20–30%. The fix is the same recalibration cycle: one full discharge to auto-shutdown, then charge uninterrupted to 100% with the phone off or in flight mode to reduce load during the first cycle.

Compatible Models

Go M1903C3GH M1903C3GG

Replaces Part Numbers

BN3A

Technical Specifications

Voltage3.85V
Amp Hours2900mAh
Capacity2900mAh
Rate11.17Wh
Net Weight43.5g /1.53 oz
Gross Weight69g /2.43 oz
Approximate Weight69g /2.43 oz
Dimension 67.40 x 57.54 x 4.50mm

Product Highlights

  • Brand: Redmi
  • 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

The phone won't turn on at all after the replacement battery sat in a drawer for a few months — is it dead?

The BMS locks out when cell voltage drops below roughly 2.5V during storage, cutting all output to prevent damage. Plug the phone into a 5V/1A charger and leave it for 20–30 minutes without pressing the power button — the charge IC trickle-charges the cell back above the BMS recovery threshold first. Once the charging LED activates or the boot screen appears, the cell has recovered. If the phone still shows nothing after 45 minutes on charge, check the cable and adapter with a known-good device before drawing any other conclusion.

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

On the first cycle after a cell swap, the charge IC sometimes defaults to standard 5V/1A input until it has completed one full charge under the new cell's impedance profile. This is normal behaviour — the IC is measuring internal resistance before allowing higher current. Complete one full charge at slow speed, then disconnect and reconnect the charger. Fast charge protocol should re-engage on the second cycle once the IC has logged a baseline resistance reading for the new cell.

The battery percentage is jumping around erratically — it went from 60% to 35% in five minutes with the screen barely on.

The coulomb counter is still calibrated to the old cell's discharge curve, so percentage readings are unreliable until it resets. Run the phone down to automatic shutdown under normal use — don't force-stop it — then charge it to 100% in one uninterrupted session. After that single full cycle, the fuel gauge IC writes a new discharge map matched to the replacement cell, and percentage reporting stabilises. If jumps continue after two full cycles, verify the battery connector is fully seated — a loose pin causes intermittent voltage readings at the gauge IC.

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