How to Add Magnet to Coil Center Without Affecting Charging

coilmagnetmagneticswireless-charging

I have a very nice wireless charger which can charge my smartwatch.

Smartwatch itself contains a neodymium magnet on its back (and there are chargers which also contain another neodymium magnet to align the charger and chargee).

This is how it looks like when a charger has the magnet:

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And this is how mine looks like:

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Mine has two coils because it can charge both watches and phones (not at the same time!)

The wires are glued onto a back plate (black one on the picture) which is kind of a metal plate (a magnet is pulling it aggressively) – to increase the coils effective (I think).

I hoped to improve my charger by adding a magnet to align my watch and keep it aligned during the charging phase.

Now, I bought some neodymium magnets and put it into the middle of the coil in my charger:

Pro: it can align my watch perfectly.
Cons: it ruins the charging algorithm, feedback led blinks red (which normally means misaligned device).

I tried with several smaller magnets, but it is always ruining the charging.

Then I have created a metal "pot" to hold my magnet and force its field towards one direction to pull the watch but don't disturb the charger coils: kindof like this:

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But this "pot" even without inserting the magnet ruins the charging algorithm.

I might have to create this pot from something else than iron, but I am out of ideas now.

Anyone has any idea I would appreciate it: how can I insert a magnet into the center of this coil without ruining the coil's effect?

Ps: I know these chargers are finetuned, and also doing protocol negotiation before and during the charging, but who knows, Community might always have some great ideas.

Update:
I have some new images of that ferrite "bed" around the coil:

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Best Answer

Think about this: -

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Ferrite material is non-conducting and therefore eddy current losses (due to induction) are very low. But, its main use is to divert the magnetic field away from the static magnet.