At 5A their “E-Scores” (in the performance and ratings table)down are essentially identical with the 50S a touch better but not noticeable in use in my opinion. At 10A the 50S would run noticeably longer but not by a huge amount.
E-Scores are the Wh delivered down to 3.2V and take voltage into account. For regulated devices it will directly tell you which will run for longer. If you are only looking at capacity delivered, and don’t care if one cell is at a lower voltage than another while running, then comparing the graphs is better.
My “longer run time” comment for the 50S was based on the Wh delivered but should hold for about any use above perhaps 7A or so. Down near 5A they’re probably about the same but let the graphs guide you.
At under 5A, down near 2A-3A the higher capacity of the F60 can finally be used and it will run for longer. Not by huge amounts but perhaps noticeably longer for the 50S ant over 7A or so and longer for the F60 at under 2A-3A.
For these two cells at the current levels you’re considering we’re starting to split hairs.
If you’re on Turbo most of the time then the 50S would be my choice. The run time difference when you’re not on Turbo just wouldn’t be that big.
As the cell manufacturers would say…to know for sure in your application you would need to test both and see which worked best.
Thanks. After mulling it over I just went with some P45B’s. They are the same price as the f60s and it made more sense to have a battery can be used in a range of devices/lights and they run much cooler too from what I saw in your tests.
I am seeing very similar results on my LG M58T - sadly my setup maxes out at 4A. But if you cut your 5A measurement off at slightly above 3.2V (where I stop discharging), the curve and mAh are very similar… Think this might be the same cell? Wish I could run higher currents.
It’s always possible but all of the ultra-high capacity 21700’s are going to operate about the same at lower power levels.
You could carefully unwrap one of your cells and compare their appearances (top contact and vent disk, surface finishes, tooling marks, bending radii, etc.). This can be a great way to sort out similarly performing cells.
For the nominal capacity rating, that’s done at some 0.2 C draw, is this correct? So for cell like F60 that would be at about a bit over an amp? Is that done down to 2.5 V OC? What’s the difference between claimed and estimated - they are often the same.
Cheers for taking time and explaining it to amateurs like me!
p.s. Is internal resistance as reported in your test tables, fairly constant and independent of the current flowing?
Correct, in this case the discharge current used to measure capacity was 1.20A.
The Claimed current rating is what the manufacturer/rewrapper is claiming is the rating(s) to be.
My Estimated rating(s) is(are) are based on my testing. I use the Claimed rating if I feel they could be correct (or higher) based on cell temperature limits and how much voltage sag I see.
My Estimated rating will not be higher than the Claimed rating as I don’t know what criteria they used and I will not tell everyone they can go higher than what the manufacturer says is okay.
If the Claimed and Estimated ratings are the same, that is good. It means I feel the Claimed ratings can be considered reasonable based on my limited testing.
If the Estimated rating is lower then that means a temperature limit was reached “early” or the cell just sagged too much in voltage for me to consider the Claimed rating to be reasonable.
This can be cecause the rating was exaggerated by the manufacturer/rewrapper or it can be that the only rating in the datasheet or on the wrap was a temperature-limited (“pulse”) rating and not a true continuous rating.
A temp-limited rating is still a perfectly valid one and multiple big manufacturers use them. But we need to know the temp limit they use and any effect it might have on cycle life when operating at the higher pulse limits.
Umm…what are you reading? It says 6000mAh.
And Estimated is right there in the ratings graphic and the Ratings & Performance table.
Wait…are you just talking generally? My previous post answers your questions I think, except for…
Yes, capacity testing is always down the the industry standard 2.50V unless a specific cell lists a different cutoff in the datasheet (rarely 2.70V or 2.75V).
