Is NFC for Verizon in the rear door whereas Sprint is in the battery?General


  1. Johnny Cakes

    Johnny Cakes Well-Known Member

    PROBLEM SOLVED: Check out this thread.

    ==============
    I have Sprint S3 model.

    I am attempting to do some mods to have the Verizon Qi charging rear cover door work with Sprint. Only problem is that the Qi charging coil and magnet on the Verizon Qi charging door covers the battery. Since Sprint has the NFC antenna in the battery, the NFC ceases to work.

    The Verizon door seems to have the NFC antenna built into the rear cover itself, and then two contacts to connect it to the phone. Can anyone with Verizon confirm that that is correct?

    In this photo, I have circled the Qi circuit in green and what I believe is the NFC circuit in Red. Can anyone with Verizon confirm that the Verizon branded phone has contacts that would match up with the contacts circled in red?

    Thanks!
    [​IMG]

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  2. Mikestony

    Mikestony ~30% Carbon Black ± Moderator

    From what I understand, the Verizon NFC is in the battery.
    I did find this video about what you are attempting and perhaps you saw it also:)
  3. klinc

    klinc Well-Known Member

    Here are pictures of the Verizon phone. The cover is just a piece of plastic. Nothing is on/in it.

    The battery has "Near Field Communication" printed on it. From what I have read it holds the antenna for it.

    [​IMG]

    [​IMG]

    Hope this helps.
    Johnny Cakes likes this.
  4. Johnny Cakes

    Johnny Cakes Well-Known Member

    The Sprint phone does not have the two contact points shown in Kline's photo next to the SIM card (and yes I know Sprint is CDMA and doesn't have a SIM card)

    @Kline, thanks for the post -- that's exactly the info I was looking for. Question: when you remove the battery, does your Verizon phone have four contacts or two? I'm 99% sure your answer will be four, but would like to confirm.

    @Mikestony: Yes, I saw that video but I think he is going about it ass-backwards. Rather harvest the NFC circuitry from the Verizon back and transplanting it into the Sprint phone (which he said took him a day the first time and two hours the second time), my thought is to use the Verizon back INCLUDING the NFC circuitry with the Sprint phone.

    From Kline's photo, it appears that the Verizon phone has ADDITIONAL NFC antenna contact points next to the SIM card. This permits Verizon to have the Qi circuitry covering the battery (thus disabling it) but then use the NFC antenna which is part of he Qi case back and connect to the additional contacts.

    So rather than harvest the Qi stuff like they did in the video, I'm thinking of running a short jumper from the NFC antenna in the Verizon Qi back cover (circled in red in my original post) to the original NFC contacts in the Sprint battery compartment.

    Unless I'm missing something (and I hope someone will alert me if there is a flaw in my logic), this mod will take about two seconds and make the Verizon Qi cover work with the Sprint phone, while keeping NFC functionality.
  5. klinc

    klinc Well-Known Member

    Definitely 4 contacts on the battery. Almost posted a pic of that too... lol
  6. Johnny Cakes

    Johnny Cakes Well-Known Member

    Actually asking about contacts on the phone in the battery compartment, not the battery itself.

    My theory is that Verizon has built in TWO different places for the NFC antenna to connect to the phone: (1) Battery compartment, for normal operation; and (2) next to SIM card for when consumer has purchased Qi rear cover.

    If this theory is correct, then the Verizon phone should have four contacts in the battery compartment: two for voltage from the battery (pos/neg) and two for the NFC antenna.
  7. klinc

    klinc Well-Known Member

    Here you go... Contacts on both.

    [​IMG]
  8. Johnny Cakes

    Johnny Cakes Well-Known Member

    Thanks for the confirmation.

    I wired it up today to prove the concept and it works fine. I am going to get some conductive cooper tape to really do it right. But the bottom line is that Verizon cover will work on a Sprint phone, and you can have NFC and inductive wireless charging with a simple one-minute modification to the battery and absolutely no modification to the phone (i.e. no warranty issues).

    I can post a You Tube step-by-step video if anyone is interested.
  9. iPredator

    iPredator Well-Known Member

    I am thinking about doing this i would like a step by step video im positive i no how to do it but just to make sure
  10. Johnny Cakes

    Johnny Cakes Well-Known Member

    I received many PM's on this one so I went ahead and created a step-by-step tutorial on how to make modifications so the Verizon inductive charging back can work with the Sprint phone. The directions are located here.

    Thanks to everyone who helped me think through this mod, especially Klic.
    iPredator likes this.
  11. pwalt

    pwalt Well-Known Member

    Sidebar:

    So if my husband switches to a non-OEM extended battery and back does he no longer have the NFC option?
  12. iPredator

    iPredator Well-Known Member

    Depends some extended battery have been tested and nfc works and some dont and some of them havent even been tested they usually say there is also a thread on here about extended batterys

    http://androidforums.com/samsung-ga...te-battery-list-cases-extended-batteries.html here you go look at some of these extended batteries some work with NFC
    pwalt likes this.
  13. Johnny Cakes

    Johnny Cakes Well-Known Member

    Even some "regular" non-OEM batteries don't have the NFC antenna built in. On eBay, some of the batteries that purport to be OEM often are counterfeit and don't have the NFC antenna. Check out this thread about the perils of eBay batteries claiming to be OEM.

    Like iPredator said, some non-OEM have NFC, some don't. Its sorta a crap shoot.
    pwalt likes this.
  14. rexster314

    rexster314 Active Member

    Yep, I bought a "genuine" Samsung battery that picture indicated NFC. When I got it no NFC of course. When I contacted the seller he didn't volunteer to replace the battery, just to send it back for a refund. So I figured what he was selling wasn't legitimate Samsung battery
    pwalt likes this.

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