My standard charging hub and power supply look they are charging batts - i.e green lights blinking, battery lights advancing to 3 dots, but it never actually charges, even overnight. Could this be a power supply issue or hub. happens with 4 sets of batteries.
The problem is it works fine sometimes!!!

Hi there. Thank you for reaching out and we're sorry for the trouble. Could you please try to use a different power cord or power supply on your battery charging hub to see if the issue persists? Or you may try to charge the batteries in the different power outlets and check if there are some changes. Please keep us posted. Thank you!

All batts had auto-discharged to 3 dots but wouldn't take any charge back up to full. I have just run one pair down to 1 dot and they seem to be fully charging now, so will try that with other 3 pairs.

Running down completely before charging  solved the issue