Best 18650 Lithium Rechargeable Batteries

I already had two of the Nikon EN-EL15c Rechargeable Lithium-Ion Batteries, but I recently purchased the Nikon MB-N11 Power Battery Pack with Vertical Grip for my Z7ii which takes two of the EN-EL15c batteries, so having a spare made sense to me. I also own several EN-EL15 batteries for my D850 and have experience zero problems with Nikon batteries.

I'm very happy with these 18650 batteries.

Best speedlight ever made!!! Namely due to the rechargeable Lithium battery that holds a charge through hundreds of uses.

Best way I've found for carrying my non rechargeable batteries

This is my first time purchasing rechargeable Lithium Ion batteries with a built-in USB charging port. That's a very convenient way to charge the battery especially if you forgot the adapter at home.

I purchased this, not for analyzing rechargeable batteries, but for measuring capacity of several different brands of lithium AA batteries. There is a common knockoff of this product that didn't actually work for my use case, but I did use it for charging batteries, and I can say that the user interface of the Powerex is much more intuitive and easier to use. As far as customer service, I emailed Powerex to find out if this would do what I was trying to do, and a representative called me and let me know that while it is not an officially supported use, it would work, which proved to be true. I would definitely buy more products from them after having that experience.

Coast’s lithium battery ZX450 all batteries that Coast supply are excellent. Reason I say this is because rechargeable lithium batteries sometimes have issues like premature failure. Things like not taking a charge, memory issues, and short run times to name a few. I do handle lion cells as recommended which is important for long life. Coast batteries and my lithium cellular batteries are the only batteries that work as promised regarding rechargeable lithium cells. I expect an a dramatic improvement with rechargeable lithium batteries of all sizes any time.

50W is very loud! Lightweight Lithium Ion rechargeable batteries. Very easy to use. I especially like the 10 second built-in memory.

I have used Watson lithium rechargeable batteries for years in Nikon, Fujifilm and Pentax cameras. No problems with battery life, recharging or performance.

It's good to have a battery testing on hand and this one does the lithium and alkaline batteries. One thing I would note is for rechargeable batteries that have been handled a lot; it a good practice to clean terminals with  isopropyl alcohol otherwise it could give inconsistent results. This is covered in the manual and in their FAQ on the website. It is not readily apparent as to why you would need to read the manual for such a straight forward device :).