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4V 0.4Ah Sealed Lead Acid (SLA) Rechargeable Battery for Slim LED Torches and Mini Electronics

4V 0.4Ah Sealed Lead Acid (SLA) Rechargeable Battery for Slim LED Torches and Mini Electronics

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ComponentSpecification
ChemistrySealed Lead Acid (SLA)
Nominal Voltage4.0V
Capacity0.4Ah (400mAh)
Full Charge Voltage4.5V – 4.6V
Terminal TypeSolder Tabs / Flat Lead Connectors
Housing MaterialImpact-Resistant ABS Plastic
Price
₹ 33.90 ₹ 33.90
(Tax included)

Product Description The 4V 0.4Ah Sealed Lead Acid battery is one of the most compact SLA power sources available, specifically designed for ultra-slim portable electronics. With a 400mAh capacity, this battery is the standard choice for pocket-sized rechargeable LED flashlights, mini emergency light strips, and small handheld testers. Its valve-regulated, spill-proof construction ensures safe operation in any position, providing a rugged and cost-effective energy solution for compact DIY enclosures where lithium-ion may not be preferred.

Key Features

  • Ultra-Slim Footprint: Specifically engineered for "micro" electronics where space is at an absolute premium.

  • Maintenance-Free: Completely sealed design requires no electrolyte top-ups throughout its operational life.

  • Stable 4V Output: Maintains a steady voltage discharge, making it ideal for driving white LEDs (3.0V-3.4V) with high efficiency.

  • Rugged ABS Case: Built to withstand the vibrations and minor impacts common in portable handheld tools.

  • Low Self-Discharge: Retains its charge effectively over months of storage compared to older Ni-Cd battery technologies.

Technical Details

  • Dimensions: Approx. 18mm x 22mm x 48mm (Standard 4V 0.4Ah footprint)

  • Standard Charge Current: 40mA (0.1C)

  • Max Charge Voltage: 4.8V

  • Cycle Life: 200–300 Charge/Discharge cycles

  • Operating Temperature: -10°C to +50°C

  • Weight: Approx. 35g to 50g

Prototyping and Engineering Tips from Robogears

  • Precision Charging: To maintain the longevity of this small cell, avoid "fast charging." A constant current of 40mA is the recommended "sweet spot." For a simple DIY charger, use an LM317 regulator circuit set to a limit of 4.6V.

  • LED Efficiency: This battery is perfect for driving 1 to 2 high-brightness 5mm LEDs. Since the battery voltage (4V) is very close to the LED forward voltage (~3.2V), you only need a small $47\Omega$ to $100\Omega$ resistor to limit current, ensuring very little power is wasted as heat.

  • Deep Discharge Warning: Small SLA batteries are very sensitive to over-discharge. If the voltage drops below 3.5V, the internal chemistry can begin to degrade. Always charge the battery immediately after use to prevent "sulfation" of the lead plates.

  • Soldering Advice: When soldering wires to the tabs, use a pre-tinned wire and a hot iron. Complete the joint in under 2 seconds to prevent heat from traveling into the plastic casing and compromising the internal seals.

Package Includes

  • 1 x 4V 0.4Ah Sealed Lead Acid (SLA) Rechargeable Battery

Disclaimer

Images are for reference; actual dimensions or casing color may vary slightly by batch. Specifications subject to change by manufacturer. This product contains lead; please dispose of it responsibly at an authorized e-waste or battery recycling center.