Batteries for HT 280 Headphones

Can someone please explain why only Avantree rechargeable batteries will work in these 'phones?
Why do non-Avantree batteries, even of the correct spec, ie the same Voltage and Amperage, not work? Do the Avantree batteries have some "secret ingredient"??
Also, are the "original" batteries available in the UK (it appears to be US only)?

I was wondering this as well. Looking at their website, it looks like only Avantree rechargeable batteries work, but I'm not sure why: https://avantree.com/product-support/WSH...-batteries
Maybe there is some "secret ingredient" involved haha.
Also, I was able to find the batteries on the UK site here: https://avantree.com/uk/battery-for-ht280

Can someone please explain why only Avantree rechargeable batteries will work in these 'phones?
Why do non-Avantree batteries, even of the correct spec, ie the same Voltage and Amperage, not work? Do the Avantree batteries have some "secret ingredient"??
Also, are the "original" batteries available in the UK (it appears to be US only)?

These were indeed engineered to be priority batteries for the HT280, however, we can speak with our engineering department. There is a loophole depending on the battery brand/model, you can take the battery wrapper off and then it will function properly. Is this something you'd be interested trying?