Elecrow Wireless Charger & Receiver Module

Overview

The Elecrow Wireless Charger & Receiver module utilizes two copper wire coils in superposition to enable wireless charging. It is designed for common use in electronic equipment requiring close-range wireless charging or power supply. The product comprises a transmitter and a receiver, capable of serving as a replacement for a Wireless Power Supply. It provides a stable 5V output voltage and a maximum 600mA output current. Its compact size and insulation coil make it particularly suitable for wireless projects.

Features

• Stable power supply
• Insulation Coil
• Space-saving design

Preview

Visual representations of the product and its application are provided:

• One image displays multiple circular copper coils, each connected to a small green circuit board via wires.
• Another image shows a single circular copper coil with wires radiating outwards to several small circuit boards arranged around it.
• A third image depicts a transmitter module connected to a handheld electronic device with a screen displaying Chinese characters.
• The final image illustrates a wireless charging setup where a light bulb is illuminated by a receiver coil placed above a transmitter coil, demonstrating power transfer.

Working Principle

Wireless charging operates on the principle of electromagnetic induction. During energy conversion, some energy is lost. The efficiency of wireless charging is determined by the magnitude of these losses. Magnetic or inductive charging has been effectively used for powering biomedical implants, offering a safe method for internal power transfer. In this system, an oscillating current in an external coil generates a changing magnetic field, which induces a voltage in an internal coil (e.g., within an implanted device). This induced current can then charge a battery or power the device directly.

While a moving magnet could generate the field, an external coil is more practical. Although current chip efficiencies may limit some advanced concepts, many smartphone users are interested in using Near Field Communication (NFC) chips for power harvesting from external or ambient sources like WiFi. Theoretically, this is possible, and systems exist, but not all NFC chips are capable. Optimal efficiency is achieved when the system is optimized for a resonant condition, akin to pushing a child on a swing at the peak of their arc.

It is important to note that if a wireless charging system consumes significant power (e.g., 10 amps from a wall outlet) just for convenient charging, it can be wasteful and slow. Alternative wireless charging technologies, such as those using ultrasound or solar power, are under development. However, magnetic inductive charging, championed by the Qi consortium and adopted by devices like the Nokia Lumia 920, is currently prevalent.

Specifications

The following table details the key specifications of the wireless charger and receiver module:

The transmitter coil and receiver coil distance is specified as 1 to 20 mm. For applications requiring a smaller current, increasing the number of turns on the receiver coil may be necessary to enhance transmission distance.

Transmitter Coil Details: Copper wire diameter 0.6mm, outer coil diameter 40mm, wound 20 turns. When connected to a 12V power source, the transmitter coil draws a standby operating current of 300mA. The load is a 4.2V 600mAH polymer lithium battery.

The transceiver's receiver output voltage is 4.2V for charging a lithium battery. If the receiving distance needs to be increased, more coil turns can be added. In practical applications, the number of coil turns can be adjusted to modify the power output.

The following table shows the relationship between transmit-receive distance, output voltage, and output current: