If you are looking here then you probably already have one of those thin wireless receivers that goes under original cover and looking for an alternative because those receivers SUX.
If not and you are thinking of getting one - DO NOT. They heat alot making your phone hot to touch, they break a water seal on the cover - and they charge VERY SLOW.
Ok now the official wireless charging cover is very good alternative which worms just a little during charging and charges much faster then one of those receivers, but probably still little slower then with a cable. But one big disadvantage is that it is thicker then original cover which adds bulk to the phone making most of the cases not fit including Otterbox Defender. You can see difference in thickness between two covers on this picture:
Here is the pictures of the original cover and wireless cover on the bottom of an Otterbox case. Note how the wireless cover sticks to the top when the original cover is flush with the case:
So I decided to modify the Otterbox Defender case (that I Love and do not want to change for anything else) so it will fit my phone with an official wireless charging cover (Of course I tried first on the cover I am not using no more). There are some Cons. to my modified case: to make the phone with wireless back fit I removed portion in the back of the Otterbox case which should reduce the protection in the back of the phone also with the back removed there is no more plastic inserts around camera and speaker. But there is still thick rubber cover in a back so you still get some protection, probably not as much as original. Also there are no more foam in a back of the case. You can see the pictures of the original back and the back with the removed portion here:
The front piece of an Otterbox case is not modified so no changes there.
Overall I love my invention because all of the futures of an Otterbox case still functional, the clip works just like with unmodified case and all the plastic inserts around the phone still present just not in a back.
So if you up to it please note that Otterbox probably won't honor the warranty on the modified case
so everything you do is at your own risk.
Modification is pretty simple. I used a Dremel with pictured attachments:
Just cut it out with a cut out attachment then make a litte slope from the bottom of the case:
and then remove all the imperfections with the knife or sand paper:
Then put a wireless cover on a bottom of a case and make sure the ends of a cover are flush with the case, if not find the pressure points and grind them some more:
And that is all there is to it. Just close it back and enjoy your phone with wireless charging capability in Otterbox Defender case.
Hope I could help someone.
If not and you are thinking of getting one - DO NOT. They heat alot making your phone hot to touch, they break a water seal on the cover - and they charge VERY SLOW.
Ok now the official wireless charging cover is very good alternative which worms just a little during charging and charges much faster then one of those receivers, but probably still little slower then with a cable. But one big disadvantage is that it is thicker then original cover which adds bulk to the phone making most of the cases not fit including Otterbox Defender. You can see difference in thickness between two covers on this picture:

Here is the pictures of the original cover and wireless cover on the bottom of an Otterbox case. Note how the wireless cover sticks to the top when the original cover is flush with the case:


So I decided to modify the Otterbox Defender case (that I Love and do not want to change for anything else) so it will fit my phone with an official wireless charging cover (Of course I tried first on the cover I am not using no more). There are some Cons. to my modified case: to make the phone with wireless back fit I removed portion in the back of the Otterbox case which should reduce the protection in the back of the phone also with the back removed there is no more plastic inserts around camera and speaker. But there is still thick rubber cover in a back so you still get some protection, probably not as much as original. Also there are no more foam in a back of the case. You can see the pictures of the original back and the back with the removed portion here:



The front piece of an Otterbox case is not modified so no changes there.
Overall I love my invention because all of the futures of an Otterbox case still functional, the clip works just like with unmodified case and all the plastic inserts around the phone still present just not in a back.
So if you up to it please note that Otterbox probably won't honor the warranty on the modified case

Modification is pretty simple. I used a Dremel with pictured attachments:

Just cut it out with a cut out attachment then make a litte slope from the bottom of the case:

and then remove all the imperfections with the knife or sand paper:

Then put a wireless cover on a bottom of a case and make sure the ends of a cover are flush with the case, if not find the pressure points and grind them some more:

And that is all there is to it. Just close it back and enjoy your phone with wireless charging capability in Otterbox Defender case.
Hope I could help someone.