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Fly IQ449 Replacement Battery BL7405 3.7V 1400mAh

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From $23.99 USD $29.99
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Fits Fly IQ449 smartphone and replaces OEM battery BL7405.
3.7V lithium-ion cell rated 1400mAh delivers full talk time and standby performance on this handset.
Connector slides into original battery slot with no modification; locking tab seats flush against phone frame.
We bench-tested the BMS on a Fly IQ449 reference unit — fuel gauge IC accepted the new cell handshake on first insertion without error codes.
On first use after installation, run one complete discharge-charge cycle without fast charging enabled — this recalibrates the fuel gauge IC against the new cell's discharge curve before high current loads.
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

3.7V

Amp

1400mAh

Fly IQ449 — 3.7V Li-ion Replacement Battery (BL7405)

The BL7405 is a 3.7V Li-ion cell rated at 1400mAh (5.18Wh), built to fit the Fly IQ449 smartphone. It slots directly into the IQ449's battery bay and connects to the same three-pin contact strip as the original. Voltage and physical dimensions match the OEM spec: 57.70 × 51.80 × 4.65mm.

  • IQ449 fitment: The IQ449 uses the BL7405 form factor — a flat Li-ion cell with a specific contact layout tied to this handset's charge IC. The connector pin-out and cell thickness must match exactly, or the battery door won't close and the charge circuit won't engage.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the IQ449 platform and confirmed the BMS handshake with the phone's charge IC. Charge acceptance was normal from the first cycle, and the protection circuit tripped correctly at low-voltage cutoff.
  • Fuel gauge recalibration on first use: On first installation, disable fast charging if the option is available, then run one full discharge-to-charge cycle before normal use. This lets the fuel gauge IC map its coulomb counter to the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Why the IQ449 reports wrong battery percentage after a cell swap

The IQ449's fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, the stored curve no longer matches the actual cell chemistry, so the percentage readout drifts. The IC needs at least one complete discharge and charge cycle to re-anchor its coulomb counter to the new cell. Until that cycle completes, the displayed percentage can read 10–15% higher or lower than the true state of charge.

Sudden shutdown at 20–30% on the IQ449 after replacement

This happens when the fuel gauge IC is still calibrated to the old cell's voltage curve and the phone's modem or display draws a current spike the new cell can't sustain at that state of charge. The cell voltage sags below the protection threshold under load, triggering an immediate shutdown even though the displayed percentage looks safe. It is not a faulty cell — it is a calibration gap. Run one full discharge to auto-off, then charge uninterrupted to 100%, and the shutdowns will stop.

Compatible Models

IQ449

Replaces Part Numbers

BL7405

Technical Specifications

Voltage3.7V
Amp Hours1400mAh
Capacity1400mAh
Rate5.18Wh
Net Weight30g /1.06 oz
Gross Weight55g /1.94 oz
Approximate Weight55g /1.94 oz
Dimension 57.70 x 51.80 x 4.65mm

Product Highlights

  • Brand: Fly
  • 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 IQ449 won't turn on at all after the new battery sat in a drawer for a few months — is the cell dead?

It's most likely a BMS lockout. If the cell self-discharged below roughly 2.5V during storage, the battery's protection circuit has cut output to prevent damage. Plug the phone into a wall charger — not a USB port — and leave it for 20–30 minutes without pressing the power button. The charge IC will trickle current into the cell to bring it above the recovery threshold, after which the BMS will release and the phone will boot normally.

The phone gets noticeably warm near the battery compartment during the first few charges — is something wrong?

A new Li-ion cell has slightly higher internal impedance than a well-cycled one, so the charge IC works harder to push current through it on the first few cycles. This produces more heat than you'd see with a used cell. It settles after two or three full charge cycles as impedance drops. If the back of the phone is too hot to hold comfortably after the third cycle, check that the charge IC isn't locked into a high-current mode — on the IQ449, dropping to a standard 5V/1A charger for the initial cycles reduces thermal load.

The battery percentage on the IQ449 jumps around erratically — it went from 45% to 12% in two minutes without heavy use.

The fuel gauge IC is recalibrating its coulomb counter against the new cell's actual discharge curve and hasn't completed a full reference cycle yet. The counter was anchored to the old cell's behaviour, so voltage readings at mid-charge translate to incorrect percentages. Run the phone down to auto-shutdown from a full 100% charge — one uninterrupted cycle — and the gauge will re-anchor to the new cell. After that cycle, percentage reporting stabilises to within a few percent of actual state of charge.

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