I took this kit of two NP-FZ100 K&F batteries to combine them with my Sony A7 IV, with the idea of using them mainly in the battery grip (not original): that is the context in which it makes sense to have more capacity and the possibility of discharging the batteries sequentially without having to stop. The fact that each one has an integrated USB-C port also makes them autonomous when charging, without necessarily going through a double charger.

The batteries are slightly different from the original Sony in terms of plastic and colors, but the construction is clean, the contacts are well aligned and the USB-C port is precisely recessed. The small LED near the connector clearly indicates the status during direct charging. In the battery grip, they are recognized regularly: the machine shows the two percentages without error messages, and the behavior in use is completely transparent, as with the originals. At the level of subjective perception, it is really reassuring to see that the grip works normally even with two compatible ones mounted.

As for autonomy on A7 IV, using them in the BG, the performance is very good: all things being equal, they seem to me to be slightly longer lived than the Sony I own, and in the field this difference can be felt. In concrete terms, however, the usual behavior that I have found on practically all NP-FZ100 compatible devices remains: if you leave them alone for a few weeks or months, they tend to download much more than the originals. It is not a specific defect of this kit, but it is an aspect on which I still have some doubts in terms of long-term management, especially if they are kept in the drawer as “spare batteries”.

Charging via USB-C is one of the most convenient points: you can charge both on two different ports (power bank, multiple charger, etc.) without taking out the dedicated charger, or use them with the Sony/K&F charger as normal NP-FZ100. This double possibility makes the kit quite flexible: when traveling, a USB-C cable is enough to get them back on track, and in the more “organized” work they are used like any other battery in a desktop charger.

In summary, I see them as a good complement to a mixed battery pack (original + compatible), especially if they are used regularly in the battery grip and kept in rotation, knowing that before an important session it is still worth recharging them if they have been unused for a little long period.