For a while now, wireless charging has been slowly gaining momentum, and one of the phones that includes support is Samsung’s Galaxy S 4 (SGS4). For the past week, I’ve been using a review unit of Samsung’s wireless charging accessory kit for the aforementioned smartphone which includes both a Qi compatible wireless charging pad and battery back.

Using the wireless charging accessory is simple – you remove the stock battery back, snap on the new one, and plug the wireless charging pad into the Samsung charger that originally shipped with the phone. This last point is critical, as the wireless charging pad requires the 2 amp charger that Samsung supplies with the SGS4. I’ve touched on charging in the past before, but this charger includes the 1.2 V signaling across the D+ and D- pins which signals 2 amp (tablet-class) compatible charging to Samsung devices, like the charging pad. Using a normal BC 1.2 compatible charger won’t work, as that specification only stipulates up to 1.5 amp delivery on its dedicated charging port.

Of course, since the charging pad and SGS4 are Qi compliant, you can obviously use a variety of wireless charging pads that implement that standard to charge the device. I tested on my go-to Energizer dual position Qi charger, and the SGS4 with wireless charging back worked as expected.

The only downside with the wireless charging back is that it does add noticeably to the thickness of the SGS4. I broke out my calipers and measured an increase in thickness of just over 1.7 mm with the wireless charging back attached instead of the stock one.

Samsung Galaxy S 4 Charging Back Thickness (Measured)
SGS4 No Battery Cover 7.20 mm
SGS4 Stock Battery Cover 7.94 mm
SGS4 Wireless Charging Battery Cover 9.70 mm

It’s not a huge difference, but it is noticeable. I suppose one benefit to this added thickness is that the front vertex of the camera no longer is the thickest part of the SGS4, which adds a bit of protection if you’re laying it back-first, on a flat surface.

The back of the wireless charging back has two sets of two contact pads that mate up with the inside of the SGS4. I tested with my DMM and on one set you get a steady 5 volts when aligned with the charging pad, on the other nothing. I strongly suspect the wireless charging downstream controller is in this battery back, so Samsung can keep their handsets relatively standards-agnostic and just ship whatever wireless charging standard back they want. In addition this obviously would help keep the BOM cost lower on the device and avoids shipping controllers that customers might not use.

So the big last question is – how well does it work and how fast does it charge the SGS4? For a while now I’ve been measuring charge times for devices, something I believe enters just as strongly into the battery and power side of a device as its time through our battery life tests. The SGS4 is already one of the fastest charging devices out there considering its battery size thanks to the speedy (albeit proprietary) 2 amp charging signaling. Because there’s overhead involved with wireless charging, this obviously gets diminished with the wireless charger. I measured a fully drained to fully charged time of 3.922 hours with the wireless charging back attached and Samsung’s charging pad connected to the 2 amp charger.

Device Charge Time - 0 to 100 Percent

That’s a measurable and obvious increase in time over the dedicated 2 amp charger connected over USB (2.883 hours, so about 35 percent longer charge time), but that’s the price you pay for the added convenience of not having to plug anything in. On the device side wireless charging is implemented properly, you see the wireless charging splash screen while charging you see the wireless charging logo with the device off, and wireless charging indicators in Android.

As I mentioned earlier, wireless charging is slowly gaining momentum. It isn’t everywhere, but it’s starting to become more and more of a given instead of a one-off. I’m still waiting for my Qi-compliant nightstand table from IKEA, or charging pads at my local cafe, but who knows when that’ll finally (if ever) happen. Obviously uptake for Samsung would be faster were the SGS4 compatible without the need for an accessory back and charging pad, but the tradeoff would obviously be a thicker phone. I’m pleased with the wireless charging accessory, it works like it’s supposed to, and wireless charging definitely is an added convenience after you’ve used it for a while. The wireless charging pad from Samsung runs for $49, and the wireless charging cover runs $39, both of which are a little steep but still around what I would expect for the pad. Of course the nice thing about Qi is that after you have the cover, you can always shop around for a pad that suits you. 

Source: Samsung (Wireless Charging Pad) (Wireless Charging Cover)

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  • pati - Tuesday, July 16, 2013 - link

    In Europe there are other wireless charging Solutions like Qinside.
  • Bob Todd - Sunday, July 14, 2013 - link

    There might be something wrong with your N4 if the UI transitions aren't smooth. Even my old Galaxy Nexus was "buttery smooth" on Jelly Bean, and my Nexus 4 is no different. Are you on 4.2.2? What version was on it when you got it? I did have any issue with the GNex where it was noticeably slower after an update (I think from 4.1.2->4.2.x). Not iOS 4 on an iPhone 3G unusable bad, but it was obvious (e.g. home screen redraw time after exiting the app drawer). I had to do a clean install from the factory image to sort it out.
  • BugblatterIII - Sunday, July 14, 2013 - link

    I'm in the UK and there are Qi charging pads available both on UK retail sites and on ebay. When I was looking for one for my S3 I found comments saying they work with the Nexus 4.
  • Alexvrb - Sunday, July 14, 2013 - link

    The more phones that make use of the Qi standard, the better. It'd be nice if it was standard rather than an add-on, though. Probably could be made a lot thinner, in that scenario.
  • uhuznaa - Monday, July 15, 2013 - link

    Does the charging pad draw any power if there is no phone on it? If it draws power leaving it connected all the time comes at a cost (and will just waste power) and having to pull the plug after removing your phone would be more than just absurd...

    I would really be interested in some numbers here.
  • Margalus - Wednesday, July 17, 2013 - link

    all chargers draw a little power even when not in use. that is why it is recommended that you unplug them when not charging.
  • shanesaccount - Tuesday, July 16, 2013 - link

    I just ordered the tylt vu. I like the design and the way the phone can be put on at any angle. Will work much better for a charging stand by the bed.
  • prasanth2u - Friday, July 19, 2013 - link

    Hi, I just bought a Qi Wireless charging kit and its pretty cool! I bought it from the Bitmore UK site.
    They have a wide range of Qi (wireless charging) Devices and the one I bought is universal. You can charge any qi enabled devices on this pad.
    Chk it out at:
  • dannanners - Thursday, August 1, 2013 - link

    There is a new wireless charger with battery bank too
    They provide a thing tag for the S4 instead of a whole cover. I think this is much thinner than the official samsung cover and probably able to use normal phone cover even with the tag is pasted.
  • SiliconSorcerer - Saturday, August 10, 2013 - link

    Until they make a "cover" that's a "case" it's of little interest.
    I want a case on a phone for a little protection, Samsung makes this simple case (which I purchased and is fine), why couldn't they make a charging pad with a case/cover solution. Until this is done it's just not interesting to me and what I can tell most people.

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