Hi,
It’s a matter of opinion but it’s also a matter of experience , performance and preference. There are a lot of great cells. I’m not going to categorize them by 18650/21700 etc etc. This is just the best cell that you believe you have and continue to use.
The VTC5D has been the best cell that I’ve used in regards to longevity( Degrades slower) and minimal, minimal voltage loss between uses and when stored for length of time. One , two years Etc.
I have used them in single cell lights but mostly 4 cell carriers. I have 2 single cells left from 5.3.2018. I believe they came out around May of 2018 when I got those original single cells that I still have left. Not used as much now but they have well over 350 cycles. And they can sit three or four months and barely lose any voltage from when they came off the charger.
I found a test from one of them. It Was 5 years and 2 months old, ( May of 2018 to July 2023) it had 370 Cycles and only lost 6.5% capacity.
I bought eight in September of 2023. They were manufactured in September of 2021. I didn’t start using them(4) until September of 2025. 4 years old before use.. They have 45 Cycles on them. I expect them to last several hundred Cycles like all the other ones.
The four that are in use , From the time they are charged until they are used, back in the rotation is usually 4 days. All four cells (the other four are still in storage) only lost 1/100th of a volt in those four days!
They have always been cells who lose very little voltage whether it’s 4 days or 4 months. Or a year or so for that matter. Performance is always good.
The VTC5D are my pick… like I said there are many others that are very good too but if I had to choose one it would be this one.
What is the best overall cell that you have used and continue to use?