(REVIEW EDIT.. I did leave it on an overnight charge and I admit it has performed very well since… used for vr headset which can eat a battery in no time.. 90 minutes usage it has barely depleted at all, headset remained fully charged while in use ) The Venom clip on battery (3500 mAh) is down to almost zero on my son’s headset playing the same game for the same length of time.
ORIGINAL REVIEW … after 8 hours of charging up using a good quality usb adapter one is still only at about 25%… I’ll leave it overnight but if it is still charging in the morning I’ll be sending it back..