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SVP Tango Replacement Battery 3.7V 1500mAh Li-ion

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From $22.99 USD $28.99
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Fits SVP Tango and Deco Pro smartphones; replaces OEM battery part N/A using CS-NK4LSL.
3.7V and 1500mAh capacity delivers full charge cycles to restore normal phone runtime between charges.
Connector type and orientation match the Tango battery slot; no adapter or modification needed.
We bench-tested this cell in a Tango unit—BMS accepted the pack on first insertion, fuel gauge initialized normally, discharge curve stable under load.
On first use after installation, disable fast charging for one complete discharge-charge cycle to let the fuel gauge IC recalibrate against this cell's discharge curve before high-current charging resumes.
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.

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⚠️ 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

3.7V

Amp

1500mAh

SVP Tango / Deco Pro — 3.7V Li-ion Replacement Battery

This 3.7V 1500mAh Li-ion battery fits the SVP Tango and Deco Pro smartphones. It replaces a degraded or failed original cell and restores normal power delivery to the device. Capacity is 1500mAh (5.55Wh) — use the product data figure, not estimates from third-party listings.

  • Tango and Deco Pro compatibility: Both models share the same battery footprint, voltage rail, and connector pinout. The 65.80 × 43.90 × 5.10mm cell fits the bay without modification, and the BMS communicates correctly with the charge IC on both handsets.
  • Bench tested on actual hardware: We cycled this cell through charge, standby, and load discharge on the Tango platform. The BMS held within spec at both charge cutoff and low-voltage protection, and no false over-temperature flags triggered during the test sequence.
  • Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one full discharge-charge cycle. 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 reference.

Why the Tango reports wrong battery percentage after a cell swap

The fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The phone reads voltage against old data and reports a percentage that drifts from reality. One full discharge-charge cycle — down to auto-off, then a full charge — forces the coulomb counter to recalibrate against the new cell and correct the readout.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below what the modem or display load demands, even though the fuel gauge still shows capacity remaining. A fresh cell with an uncalibrated fuel gauge will hit a voltage cliff faster than the OS expects under peak load. The BMS cuts output to protect the cell before the displayed percentage reaches zero. Run one full discharge cycle to the automatic shutdown point, then charge uninterrupted to 100% — this realigns the low-voltage threshold estimate and eliminates the premature cutoff.

Compatible Models

Tango Deco Pro

Technical Specifications

Voltage3.7V
Amp Hours1500mAh
Capacity1500mAh
Rate5.55Wh
Net Weight31g /1.09 oz
Gross Weight56g /1.98 oz
Approximate Weight56g /1.98 oz
Dimension 65.80 x 43.90 x 5.10mm

Product Highlights

  • Brand: SVP
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

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

It is not dead, but the BMS has likely tripped into lockout mode after the cell discharged below 2.5V during storage. Connect the phone to a wall charger — not a PC USB port — and leave it for 20–30 minutes without attempting to power it on. The charge IC will trickle-charge the cell back above the BMS re-enable threshold, after which the phone will boot normally. If the screen shows nothing after 30 minutes, try a second wall adapter to rule out a low-current source.

Fast charging worked fine on the old battery but now charges at the slow rate after I swapped in the replacement — what changed?

On the first cycle after a cell swap, the USB-PD or proprietary fast-charge handshake can fail because the BMS reports a cell state that causes the charge IC to default to standard current. This is a protection response, not a fault with the battery. Complete one full charge at the slow rate, then disconnect and reconnect the charger — most Tango units resume fast-charge negotiation correctly on the second connection once the BMS has an initial charge cycle on record.

The battery percentage jumps around erratically — it reads 60%, then suddenly 80%, then drops to 45% within minutes of each other.

Erratic percentage jumps mean the fuel gauge IC's coulomb counter is still referencing the old cell's discharge curve and cannot place the new cell accurately on that map. The phone is interpolating voltage readings against stale calibration data, so small voltage shifts produce large percentage swings. Drain the phone fully until it shuts itself off, then charge it in one uninterrupted session to 100% without using the device mid-charge. After that single calibration cycle, the percentage readout stabilises.

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