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Emporia Smart 5 Compatible Battery AK-S5 3.85V 3500mAh

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Fits Emporia Smart 5, Smart.5, EMS5 smartphones; replaces OEM part numbers AK-S5 (V2) and AK-S5-BC.
Voltage 3.85V, capacity 3500mAh (13.48Wh) restores full charge cycles lost to age-related degradation in the original cell.
Connector type is a two-pin proprietary Emporia Smart 5 slot with brass contact alignment — no tab, straight vertical insertion.
We bench-tested this cell in a Smart 5 dock charger; BMS accepted the new pack on first power-on with no fault codes or voltage limiting.
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 pushes current into an uncalibrated cell.
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

3.85V

Amp

3500mAh

Emporia Smart 5 — 3.85V Li-Polymer Replacement Battery (AK-S5 (V2))

This is a 3.85V, 3500mAh Li-Polymer battery for the Emporia Smart 5 smartphone. It fits the Smart 5, Smart.5, and EMS5 variants. Capacity and connector match the original AK-S5 (V2) and AK-S5-BC cells directly.

  • Smart 5 / EMS5 compatibility: The Smart 5, Smart.5, and EMS5 all share the same battery bay dimensions and connector pinout. The BMS handshake uses the same thermistor line across all three variants, so one cell covers the full range without modification.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the Smart 5 platform. The BMS accepted the cell without flagging an unrecognised pack, and the charge IC stepped through its standard CC/CV profile without interruption.
  • Fuel gauge recalibration 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 map the new cell's discharge curve before fast charging pushes high current into an uncalibrated state.

Sudden shutdown at 20–30% on the Emporia Smart 5 after a cell swap

When a new cell goes in, the fuel gauge IC still holds the discharge curve from the degraded original battery. It underestimates how steeply the new cell's voltage drops under load — particularly under modem transmission bursts or screen-on peaks. The phone hits its low-voltage cutoff while the gauge still shows 20–30% remaining. One full discharge-charge cycle at standard rate forces the coulomb counter to relearn the curve against the actual cell, and the phantom shutdowns stop.

Device not powering on after the replacement cell sat in storage

Li-Polymer cells self-discharge in storage. If the cell drops below roughly 2.5V per cell, the BMS enters lockout to prevent damage and blocks normal startup. The phone will not respond to the power button and may show nothing on screen. Connect the phone to a wall charger — not a PC port — and leave it for 15–20 minutes without pressing anything. The charge IC trickle-charges the cell back above the BMS recovery threshold, typically around 2.8V, at which point the BMS re-initialises and normal charging resumes.

Compatible Models

Smart 5 Smart.5 EMS5

Replaces Part Numbers

AK-S5 (V2) AK-S5-BC

Technical Specifications

Voltage3.85V
Amp Hours3500mAh
Capacity3500mAh
Rate13.48Wh
Net Weight51g /1.80 oz
Gross Weight101g /3.56 oz
Approximate Weight101g /3.56 oz
Dimension 80.00 x 56.50 x 4.50mm

Product Highlights

  • Brand: Emporia
  • 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 Emporia Smart 5 keeps shutting off around 25% after I put in a new battery — what's wrong?

The fuel gauge IC is still running on the discharge curve it learned from the old, degraded cell. When the new cell's voltage drops sharply under load — a screen wake or a mobile data burst — the phone hits its cutoff threshold while the gauge still reads 25% or higher. Run one full discharge to the auto-off point, then charge uninterrupted to 100% at standard speed with fast charging disabled. That single cycle recalibrates the coulomb counter against the actual cell, and the early shutdowns stop.

Fast charging stopped working on my Smart 5 right after I replaced the battery — is the charger broken?

The charger is most likely fine. On the first cycle after a cell swap, the charge IC on the Smart 5 can reject the fast-charge handshake because the BMS presents higher impedance on a fresh, unconditioned cell. The IC defaults to standard 5V charging as a precaution. Complete one full charge-discharge cycle at standard rate, then reconnect your fast charger — the IC re-evaluates the cell impedance on the next session and the fast-charge protocol resumes normally.

The battery percentage on my Smart 5 is jumping around erratically — 60% one minute, 45% the next — after the swap.

This is the fuel gauge IC recalibrating after the cell change. The IC uses a stored model of the old cell's voltage-to-capacity curve, and the new cell doesn't match it, so percentage readings become unstable under any load shift. Let the phone discharge fully until it shuts itself off, then charge it to 100% in one uninterrupted session with the screen off where possible. After that cycle, the IC rebuilds its internal model against the new cell and the percentage readings stabilise.

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