Watson EN-EL15 Lithium-Ion Battery Pack (7.0V, 1900mAh)

The Watson EN-EL15 Lithium-Ion Battery Pack (7.0V, 1900mAh) can not be charged from the camera.

Although it is possible to use EN-EL15 and EN-EL15a batteries in the new Nikon Z7 and forthcoming Z6 cameras, only the new 15b version is able to be charged while inside the camera.

i brought two batteries. one works okay but the other does not respond in my D3100.

From what I have read lithium Ion cell in after market batteries are all inferior to the cells Nikon uses. I have had some experience with aftermarket Nikon batteries, to me they are not worth the trouble especially if you are doing video. If you are doing any significant amount of video use a power grip with AA energizer lithium batteries, that should get you 3 to 4 hours of run time at least in my experience.

It likely should work as it did work in my D750, D500 and D850. But personally, I would not use it for an important photoshoot and would not primarily rely only on this single one in any Z. I feel like I had about 20%-30% reduction in this battery life performance in D750, compared to a Nikon battery that came with D750 (B&H sent me Watson as an extra/add-on with D750), and had even more battery life reduction in a more power demanding D850. Now, given that Z7 consumes more power compared to D850 (based on the number of shots), this battery might be quite a disappointment to use in a Z. Additionally, this battery loses quite noticeable amount of charge when taken out of the camera and not in use, just sitting in a drawer. I would suggest to stick with an original Nikon battery in a Z.

Yes, it is compatible.

Yes this battery is fully compatible with the D750, with or without a battery grip installed.

Yes, it will work in the Z7.