ok to add metal disc between battery and coil?
I am modding a S4 for touchstone charging while mounted vertically in my car... so I need to add some metal or magnets to the battery cover so it holds the phone to the dash in the car. I have a touchstone coil card from ebay (made for the S4 charge points), so here's what I'm thinking:
1. use double side tape to attach coil card to the inside of my S4 battery cover (after confirming alignment of charge pins)
2. tape a thin metal circle (1.75" diameter , cut from an altoids can) to the coil card center, so the metal circle, coil card, and battery cover are all one flat piece.
3. Put cover on phone and phone on touchstone.
Since the touchstone has -some- grip on the S4 already, I'm hoping this extra metal will increase grip for vertical hold over speed bumbs/potholes, while not disrupting the magnetic field between the phone's coil and the touchstone's coil (since it sits between the battery and phone coil, not between the 2 coils like a metal battery cover would.)
If this mod isn't to thick , and the battery cover snaps on properly, are there other issues I should consider? should I be concerned about temp rise or fire risk? or would it charge slower from the metal proximity? Fishing for advice and theories, any input from modders helps.