Welcome to our store. Your trusted source for batteries and power solutions. Learn more

For support or quotes: sales@batteryweb.com
WELCOME5
BatteryWeb

Kazuna eTalk 4G BP1578 Replacement Battery 3.8V 1400mAh

Up to 20% off
New arrival
From $25.99 USD $31.99
Shipping calculated at checkout.
Fits Kazuna eTalk 4G and compatible models using OEM part number BP1578 battery.
3.8V and 1400mAh capacity matches the original cell voltage and charge storage for this senior-friendly smartphone platform.
Connector aligns with the eTalk 4G battery slot — standard Li-Polymer contact orientation, no locking tab interference.
We bench-tested the BMS against the fuel gauge IC on power-up; charge acceptance was clean on the Kazuna platform.
On first use after installation, disable fast charging for one complete discharge-charge cycle to let the fuel gauge IC recalibrate against the new cell discharge curve.
Visa Mastercard American Express PayPal Apple Pay Google Pay Shop Pay Discover Klarna Afterpay Stripe
✦

Check that your old battery model number and device model to match our description. This makes sure they work together.

✦

We ship your order same day if you buy it before 4 PM EST.

Warranty

Let customers speak for us

from 11 reviews

Product is exactly as described and arrived quickly

Robert Jones
Rocket ES4-12 Compatible Replacement Battery

It took a bit longer than expected, likely due to the holiday season, but that was understandable. So far, the battery seems to be working well!

Linda M.
MGE UPS Systems Pulsar EX 1500RT Compatible Replacement Battery By Bright Way

Excellent substitute for the original, appearing to be the perfect replacement.

Alberto J.
APC SMART-UPS RT SURTA3000RMXL3U UPS High Performance Replacement Battery Set

It was what i was looking for. Support is fast

Jaswal
WAHEGURUG - RADHASWAMI

Fast service

Mark Casias
BatteryWeb

Perfect fit

Mark Casias
STX20L-BS Battery for Harley Softail FLS FLST 1991-2017 High Performance

Works Perfectly!!

Ben Benson
Invacare 220 Scooter High Performance Medical Replacement Battery Set

Send Your Battery Photo

Expert Technician Help

Snap a photo or video of your battery and send it to us. We'll identify the exact replacement—fast and hassle-free. Our team has helped thousands of customers find the right battery quickly and easily.

POST YOUR BATTERY IMAGE
Product & Solutions Expert

Product & Solutions Expert

✉ sales@batteryweb.com

🔹 10+ Years Battery Experience 🔹 Fast & Accurate Identification

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

3.8V

Amp

1400mAh

Kazuna eTalk 4G / KAZ-F019 — 3.8V Li-Polymer Replacement Battery (BP1578)

This 3.8V, 1400mAh Li-Polymer cell replaces the BP1578 battery in the Kazuna eTalk 4G and KAZ-F019 series handsets. It fits the senior-focused eTalk lineup, including KAZ-F019PP and related variants. Capacity is 5.32Wh — matching OEM specification from the product data.

  • eTalk 4G / KAZ-F019 platform fit: The KAZ-F019 and KAZ-F019PP share the same battery bay dimensions and connector pinout. The BP1578 designation is consistent across these variants, so one cell covers the full eTalk 4G range without modification.
  • Bench tested on actual hardware: We cycled this cell through a full discharge-charge sequence on the eTalk 4G platform and confirmed the BMS accepted charge termination correctly — no false-full cutoff and no trickle-lock at low state of charge.
  • Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the fuel gauge IC one full reference cycle against the new cell's discharge curve before it starts tracking percentage accurately.

Why the eTalk 4G shuts off suddenly at 20–30% after a cell swap

The eTalk 4G's fuel gauge IC retains the discharge curve learned from the original degraded cell. When a new cell is installed, the IC's voltage-to-percentage mapping is out of sync. At around 20–30% displayed charge, the actual cell voltage drops below the threshold the OS expects for that percentage, triggering an emergency shutdown. This is not a cell defect — it is a coulomb counter calibration mismatch. One full uninterrupted discharge-charge cycle resets the reference curve and resolves the cutoff.

Phone warm near the battery during the first charge after replacement

A new Li-Polymer cell has higher internal impedance than a broken-in cell. On the first charge cycle, the charge IC pushes current into that higher-impedance cell, which generates more heat than normal. This typically appears during the constant-current phase of charging. It is self-limiting — impedance drops after one or two cycles and the warmth normalises. If surface temperature stays below approximately 40°C and drops after 20 minutes, no action is needed; if it continues rising, disconnect and check connector seating.

Compatible Models

eTalk 4G KAZ-F019 KAZ-F019PP eTalk KAZF019PP 440G KAZ-F119

Replaces Part Numbers

BP1578

Technical Specifications

Voltage3.8V
Amp Hours1400mAh
Capacity1400mAh
Rate5.32Wh
Net Weight28.6g /1.01 oz
Gross Weight53.6g /1.89 oz
Approximate Weight53.6g /1.89 oz
Dimension 57.42 x 45.50 x 4.66mm

Product Highlights

  • Brand: Kazuna
  • 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 Kazuna eTalk 4G won't turn on at all after I put the new battery in — is it bricked?

Most likely the replacement cell discharged below 2.5V during storage and the BMS has entered lockout mode to prevent cell damage. Plug in the original charger and leave it connected for at least 20–30 minutes before attempting to power on — the charge IC needs to push enough current through to bring the cell above the BMS re-enable threshold. If the charging LED lights up during that window, the cell is recovering. Once the indicator appears, leave it connected until the device boots on its own.

The battery percentage on my eTalk 4G jumps around erratically — it was at 60%, now it says 85%.

The fuel gauge IC is recalibrating against the new cell's discharge curve and hasn't completed a full reference cycle yet. The coulomb counter stored data from the old degraded cell, so percentage readings are unreliable until it relearns. Run one full discharge to auto-shutdown, then charge to 100% without interruption. After that single cycle, the IC has a clean reference point and percentage readings stabilise.

Fast charging stopped working after I replaced the battery on my eTalk 4G — it only slow charges now.

On the first cycle after a cell swap, the BMS on the new cell may not immediately handshake with the charge IC's fast-charge negotiation sequence, so the device defaults to standard 5V charging as a fallback. Complete one full slow charge to 100%, then disconnect and reconnect the charger. On the second cycle, the BMS handshake completes correctly and fast charging resumes. If it still defaults to slow charge after two full cycles, check that the USB port is clean and seated fully.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • Mastercard
  • PayPal
  • Shop Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

Related Products

Kazuna eTalk 4G Replacement Battery, 3.8V, 1400mAh, Li-Polymer 1

Engineered for Performance. Built to Last.

Check out our top-rated selection of reliable products built to last. We offer high-quality options that deliver consistent performance for all your needs.

Our Collections