Hafele dimmer switches causing LED flicking

[Wills]

I have 2 X Hafele dimmer switches in use with 1M LED light strips that share the same 12v supply. They both work fine individually but when they’re on together both LED strips flicker.
I’ve fed 1 dimmer direct from the LB and that eliminates the flicker.
I’ve used a 12v USB feed for 1 dimmer and there’s flicker.
I’ve used the heavy duty fridge supply with 1 dimmer and that eliminates the flicker.
Is there a common issue with this set up and is there a recommended solution? I’m assuming some sort of dimmer interaction with the supply voltage? How can I isolate the supplies? Any other possibility?

 

[roadtripper]

The dimmers will likely be doing PWM to dim LED. They shouldn't really be putting any kind of pulsing load on the power supply but it sounds like they might be, or part of the PWM signal is inductively coupled across the cables.

What wattage are your LED strips? Possibly with both on you are getting voltage drops?

 

[roadtripper]

Electrical noise on the cables can often be dealt with using a snap on ferrite core on the supply cable - a lot of laptop power supplies have them - but my suspicion at the minute is voltage drop as it seems to go away when you use higher current capacity feeds.

 

[Wills]

I’m using COB LED’s but did have cheaper standard LED’s but they both experienced the same.
I suspect voltage fluctuation / induction so have reasonably separated the supplies but no joy.
The thought is to isolate both feeds so there’s no interaction but how to with the 12V supply?