Hello.
I have a wireless charging base for my phone.
Last week I was gifted a portable battery thingy that has a wireless charging pad built in. (Samsung EBU1200 https://www.samsung.com/us/mobile/mobile-accessories/phones/wireless-charger-portable-battery-silver-eb-u1200csegus/ )
I am going to presume that I should not put the portable battery on top of the phone's wireless charger, but should I keep them well away from each other as well?