While I rarely see an issue like yours, I can say in about a dozen purchases where I was in a hurry and could not find the right make battery, only one was defective. That's still quite high but at least it was easy to return but annoying.
Being new to these forums, I didn't realise that there is this Sony forum, so I post below what I have posted in a different forum:
I have returned "100% compatible with NP-F970" batteries from two different sellers because of the following problems:
Tried to charge using my Sony HXR-NX5E charger - don't know whether the small LED in the middle of the battery is supposed to come on at any stage but it did not - 6 hours in the charger, the charger light remained on (meaning that the battery has not charged in 6 hours) - battery not even getting warm - tried on my NX5E - shows only 120 minutes much less than my Sony original NP-F570 (which works perfectly well).
I'm beginning to feel that these cheap clones for pricey item like Sony NP-F970 have design/ manufacturing fault and public is wrongly tempted to buy these.
Wondering about others experience regarding this issue!