Samsung Launches Galaxy S4 Inductive Charging Kit at $90

For those who have a Samsung Galaxy S4, have you ever wondered what those two pairs of metal prongs are at the back, close to the SIM card? Samsung has officially released their native inductive charging kit, which comes with a charging pad and a special back cover which utilizes the four prongs for charging your battery for wireless inductive charging. The charging kit is available from online shops such as "shopandroid.com," at current discount prices of $89.99.

Wireless inductive charging has become more readily available for advanced consumer electronics (we say advanced, as it's been in your electric toothbrush for decades), and it is becoming more popular due to its ease of use. The theory behind the technology involves having a coil of wire in each device, where one can induce a voltage across the other due to electromagnetic coupling, even through some solid objects. This is due to a collapsing and growing electromagnetic field produced by the alternating current in the charging pad, which then induces eddy currents in the other coil (similar to a voltage transformer). While the advantages are near-zero risk of shock, convenience and less broken cables/docks, unfortunately, the charging is slow because larger amounts of power are very inefficient, and you cannot move your phone about while charging.


The charger kit is compatible with all other QI charging devices but has a limit of 500 mA which, while it is faster than a USB port of your computer, it has four times less power than the cable can get from a wall socket (nearly 2 A). Apart from the lower power, there has been much uproar concerning the price of the kit. Because the kit only includes the charging pad and a slightly different rear cover for the phone, consumers have been scratching their heads as to the $90 price. While we expect the price to come down over time, the wireless charging solution from Samsung is much easier to implement than trying to place a kit in an HTC One or similar. So, would you consider buying a wireless inductive charging kit for your phone, and are your reasons purely based on finances or also practicality? Tell us what you think in the comments below.

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  • livebriand
    "but has a limit of 500 mA which, while it is faster than a USB port of your computer, it has four times less power than the cable can get from a wall socket (nearly 2 A)." Not quite - most computer USB 2.0 ports are exactly 500mA. Phones tend to pull 1A from wall chargers, and tablets 2A. (USB 3.0 is 900mA, but I haven't seen any phones or tablets that support it. In fact, my phone only pulls 500mA when plugged into a computer even if 900mA is available, yet it pulls 1A from a charger.) (Earth to toms: PLEASE fix the issue with line breaks causing generic errors...)
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  • Grandmastersexsay
    For $20, I would definitely buy it.

    For $50, I might buy it.

    For $90, Not a chance.

    On Amazon, $72.28 can buy you a spare battery and the spare battery charger, all made by Samsung, not the cheap knock off stuff. It is just not worth it. I mean, how hard is it to plug a phone in? $90 is a rip off for something that should have came stock with the phone.
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  • InvalidError
    " the alternating current in the charging pad, which then induces eddy currents in the other coil"

    Wrong thing. Eddy currents develop from tiny voltages induced within a conductive material passing through a changing magnetic field. The small voltages within the material create conduction currents and associated I2R losses within the material so for most applications, they are considered parasitic - undesirable. Since larger chunks of conductive materials are more severely affected by eddy losses, efficient transformer call for magnetic cores with smaller metallic components to constrain eddy currents within smaller volumes of conductive material. That's why low-frequency transformers use laminated steel coated in non-conductive enamel/lacquer/resin instead of solid chunks and why high-frequency cores use powdered metal mixed with ceramics to constrain eddy currents within individual metal dust particles, thereby reducing I2R losses within materials.

    Magnetic coupling is what enables transferring energy between two electrically isolated coils using magnetic fields, usually using a magnetic core material to guide magnetic flux along a predetermined path.
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