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Cat S40 Smartphone Replacement Battery 3.8V 2900mAh

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From $25.99 USD $31.99
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Fits Caterpillar S40 phones and replaces OEM part number 458002-S40.
This 3.8V lithium-polymer cell supplies 2900mAh capacity for calls, messaging, and apps.
Connector plugs straight into the S40 slot with standard push-release tab orientation.
We charged the pack on a standard Li-Polymer profile; the BMS accepted full voltage without fault codes.
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 7 – 10 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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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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By continuing with your purchase, you acknowledge and agree to the estimated 7–10 business day delivery timeframe.
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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

3.8V

Amp

2900mAh

CATERPILLAR S40 — 3.8V Li-Polymer Replacement Battery (458002-S40)

This 3.8V, 2900mAh lithium-polymer battery is a direct cell replacement for the CATERPILLAR S40 rugged smartphone. It fits the S40's internal battery bay and reconnects to the phone's charge IC and fuel gauge circuit via the original flex connector. Capacity matches the factory spec at 11.02Wh.

  • S40 platform fit: The S40 uses a fixed internal battery with a proprietary flex connector tied directly to the fuel gauge IC. This cell matches the voltage rail, physical dimensions (95.65 × 55.64 × 3.35mm), and connector pinout so the BMS handshake completes on first boot.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on the S40 platform. The BMS accepted the new cell without fault codes, and the coulomb counter initialised correctly after one complete cycle.
  • Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map its reference curve against the new cell before high-current charging begins on an uncalibrated counter.

Sudden shutdown at 20–30% on the S40 after a cell swap

This happens when the fuel gauge IC is still running the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff at low state-of-charge, so the phone hits the hardware undervoltage cutoff before the OS percentage reaches zero. The phone shuts down even though the reported figure looks safe. One full discharge-charge cycle recalibrates the coulomb counter to the new cell's actual curve and eliminates the early cutoff.

OS reporting erratic or stuck battery percentage after replacement

The S40's fuel gauge IC stores a learned model of the old cell's capacity and self-discharge rate in non-volatile memory. When a new cell goes in, that stored model no longer matches reality, so percentage readings jump, stall, or read 100% immediately after a short charge. Drain the phone fully until it shuts off, then charge uninterrupted to 100% without interruption. After that single full cycle the IC writes a new baseline and percentage reporting stabilises.

Compatible Models

S40

Replaces Part Numbers

458002-S40

Technical Specifications

Voltage3.8V
Amp Hours2900mAh
Capacity2900mAh
Rate11.02Wh
Net Weight44.6g /1.57 oz
Gross Weight80g /2.82 oz
Approximate Weight80g /2.82 oz
Dimension 95.65 x 55.64 x 3.35mm

Product Highlights

  • Brand: CATERPILLAR
  • 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

My Cat S40 shuts off at around 25% after fitting the new battery — is the cell faulty?

The cell is not faulty. The fuel gauge IC on the S40 is still using the discharge curve it learned from the old, worn cell. The new cell has a sharper voltage drop at low charge, so the phone hits its hardware undervoltage cutoff before the displayed percentage reaches zero. Run one full uninterrupted discharge until the phone powers off, then charge to 100% without interruption. After that cycle the coulomb counter recalibrates and the early shutdown stops.

Fast charging stopped working on my S40 after I replaced the battery — USB charging works but it's slow.

On the first cycle after a cell swap, the S40's charge IC can fall back to standard 5V charging because it has not yet confirmed the new cell's impedance profile. This is a protective default, not a fault. Run one complete standard charge to 100%, then reconnect the charger. The charge IC re-evaluates the cell on the second cycle and fast charging resumes. If it does not resume after two full cycles, check that the battery flex connector is fully seated — a partial connection raises measured impedance and keeps the IC in slow-charge mode.

The S40 won't turn on at all after the replacement battery sat in a drawer for a few months before I installed it.

Lithium-polymer cells self-discharge in storage, and if the cell dropped below approximately 2.5V the BMS will have locked out to prevent damage. The phone will not respond to a short press or standard charge attempt in this state. Connect the phone to a wall charger — not a PC port — and leave it for 20–30 minutes without pressing anything. The charge IC trickle-charges the cell back above the BMS re-enable threshold; once it crosses roughly 3.0V the BMS unlocks and the phone will power on or show a charge indicator.

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