AZ16-1 EforTek Replacement Battery(2 Packs) and Dual USB Charger for Xiaomi YI 4K,Yi 4K+,Yi Lite,YI 360 VR Action Camera，100% Compatible with Original

This charger and 2 batteries work great for my Yi 4k camera. Finally happy. I originally bought a different advertised charger on amazon that could charge 3 batteries at once and came with 2 batteries but none of it was compatible with the Yi 4k though it said it was.

Batteries work well in my YI 4K+ Acton Camera. The dual battery charger is really nice as the camera does not come with a stand alone charger. Only reason I'm not giving 5 starts is because they do not last as long as the factory battery. These appear to be giving about 20 min less run time. I am getting about 2 hours of continuous recording at 4K-30FPS per battery. Update on these batteries.... they are still working fine but they do not seem to hold a charge as long as when new. Currently I get about 1:15 - 1:30 per battery while shooting at 2.7k @ 60fps. I've also notices that this charges seems to stop charging at about 85% capacity. To fully charge the batter I must charge via the camera. Only this way can I get the batteries to 100% each. Also, if the battery sits for a few days unused the charge will drain. 3 - 4 days of none use will result in the battery going from 100% to about 60%. They are still very useful and I'm glad I have them, just not as functional as I had hoped. Dropping my rating to 3 stars.

This charger has a nice feel - good fit and finish, and a decent heft, if not quite as weighty in the hand as I would have liked. It comes in a plain box, with two batteries, a charger and a Mini USB cable (as shown in the image above). NOTE - THERE IS NO MAINS CHARGER INCLUDED. One thing I prefer about these batteries over the original is that the little plastic pull tab on the bottom (used to extract the battery from the bottom of the camera), are positioned well away from the battery door hinge. This makes it far easier to extract them from what is a fairly small aperture. This means you need to find yourself a mains powered USB charger to drive this from. Without that, you will be dead in the water. I used my Trusty 36W, 4 port, Anker charger, a previous generation of the one found here: Anker 40W 4-Port USB Wall Charger This charger will supply a total of more than 4 Amps, way more than the 2 Amps the charger will max out at. The charger will supply a maximum of 750mA to each battery whilst charging. Not exactly lightning fast, but not fast enough to risk damaging the batteries either. Out of the box, each battery came with exactly the rated voltage of 3.85V, which meant they needed a good charge. I plugged them into the charger, connected it to the Anker, and let it charge. The LED indicator for each battery shows green when open or charged, and red under charge - always nice to have visual confirmation that the charger is doing its job. It took about an hour and ten minutes for each battery to charge to 4.3V - the same value as the OEM battery got when being charged through the camera. *Edit* After three weeks on the shelf, batteries are at 4.27 & 4.28V. One quirk to be aware of is that if you power on the charger and then insert the batteries, the LEDs may remain green (not charging). Instead, plug batteries in first and then connect charging cable in order to ensure correct operation. All in all, this is a good basic charger with what could be decent quality batteries (no idea regarding life cycles at this time), and functional piggy-back charger. Supplement it with a good USB charger unit and you get the ability to either charge two Yi 4K batteries at the same time, or charge one whilst another is in use. You can probably almost charge two batteries in the time it takes the camera to exhaust one battery.

These were the wrong sized batteries, completely for this camera! I purchased them for my Yi 4K Mirrorless camera. I have the movie camera, looks like a dslr. These batteries proved to be roughly 2/3 the size I needed. In disgust and frustration, I never sent them back. Since I have checked on Amazon, no luck, anything I might see seems like it could be for the other, evidently more popular models. The sellers are no help, and the manufacturer created a problem in not more clearly naming different models. I'm left with running around town on mass transit, camera over the shoulder, to different camera sellers, and hoping. This IS a glaring example of why I despise proprietary batteries!

Great price on this two pack of batteries for the Yi 4K Action Camera. The batteries don't last quite as long as the original battery but they are still a great value.

Drained 10% on the shelf after a week, make sure you top them up before filming. For the price, it's acceptable but I would recommend something else if you have a choice

These batteries work great! Far superior to the battery that came with my YI Lite Action Camera which failed twice while videoing my sons hockey games not even half the game even though it showed plenty of battery left on the display. Of course we missed two of his best saves he has made all year, which is why you buy the camera. I highly recommend using these Efor Tek batteries they last a full game no problem.

Very nice batteries, work great with my xiaomi camera. One battery lasts for about a couple of hours of straight footage.