It will be interesting to see what you get for results. Yes, the top is added since from the factory the cells have a special cap for Teslas battery pack. The Sanyo ncr21700A is a 4800 mah nominal cell for 10A CDR. I think the internal resistance is between 20-30 miliohms. It will be interesting to see how many mah’s escaped and how much the internal resistance has changed.
You better pick one before they are all gone. It’s slim pickings on most reputable sites.
I just received 3 from Tech Direct and they were packaged the worse I’ve ever seen. They were thrown together into some bubble wrap and then into a generic gray plastic envelop. However the bubble wrap container wasn’t taped to seal the batteries inside of it and they arrived flopping around in the gray plastic with the bubble wrap off the the side. So basically a few mil of plastic protecting the batteries from the bumps they got being shipped to me 
Also no tape over the contacts or anything to keep the batteries separate from each other. And I thought there were regulations on how lithium batteries were supposed to be shipped!
Oh well at least there aren’t any dings or divots on them.
Getting back to the batteries themselves…they all read at 3.68v with IR’s of 80, 71, and 74. However this is off of my Opus 3100 and to be honest I don’t think it’s very accurate so take those with a large grain of salt.
I’m in the process of charging them and will have discharge readings probably tomorrow.
That’s dangerous. The batteries ideally need to be in a protective case like every other seller I’ve bought from.
So very very true. My 2 year old grand-daughter could have done a better job packaging them up.
I wonder how they were packaged for others who bought from them? I assume better, couldn’t have been any worse, since nobody mentioned anything.
Edited to say that I sent them a message telling them about the poor packaging. Let’s see if they respond to it.
My pack of 5 came in a cardboard divider pack, looks like it was specially made for 21700 batteries (or at least other similar-sized cylindrical batteries). Probably the best battery packaging I’ve ever seen. Odd that yours were so poorly packed and mine so well.
Mine were wrapped up inside a pinkish red sheet of foam, then the foam sheet was held together with some sort of black cling wrap… inside a tyvek bag… Loose, just rolling around inside with nothing protecting the terminals. I was surprised when they weren’t in a case.
Sounds like packaging is all over the board. Hopefully they’ll respond to my message, or at the very least package future shipments in a safe manner.
My three came last saturday or so… packages in the grey plastic with no markings and inside a clear bubble wrap with packing tape. I do have testing equipment to easily test up to 3A. The higher current testers are a PITA to work with for these small tests and I don’t think these seem like they are going to be useful in high current lights by the sound of it. Won’t get around to it til next week but I can share some curves if people care to see them
Just finished grading the other 4 Tesla 21700s I received. All 4 came out in the 4400mah capacity range, well under rated minimum. So again, these seem to be salvage cells already in their middle age, already down 10%. They’ll be useful to me as backup and in my low-amp Convoys, but not for my top tier lights. Not unhappy with them for the price but they are what they are.
Mine just arrived and they have recessed tops… do not work in my charger without special treatment. Just an FYI
The tops on the 3 I got aren’t recessed and work just fine on my Opus 3100. I don’t have anything that discharge at more than 1A and these are the results. They were fully charged on my Accucell-6 last night and discharged this morning using my Opus 3100 (only charges to 4.15v).
Volts off charger / Volts this morning / Capacity
4.19 / 4.17 / 4655
4.19 / 4.17 / 4564
4.18 / 4.16 / 4664
Dug the old “Nitecore New i4” out of the closet and it charges the Epoch fine. I avoid that charger because it gets hot enough to fry an egg, but it is good enough for now and I watch it closely. The batteries do not heat up, just the power supply, so their are probably no real safety issues… I just am uncomfortable with it. The Epochs shipped fast and arrived early. Very happy with the purchase.
Charged mine up last night, and discharging two right now (my charger only has two 1A slots).
Fresh off the charge, all three were 4.22V, and in the morning 4.2V. All checked with my DMM.
I finished testing two cells earlier… the third one will be maybe tomorrow night.
My results are:
Cell #1: 4841mAh
Cell #2: 4833mAh
Testing was on my Vapcell S4 Plus at 1A from full charge 4.2V, down to 2.5V. I let them rest for an hour, and the voltage bounced back to 2.89V. Voltages were checked with a DMM.
I’m curious how many mah you gained from 2.9v to 2.5v —- got to be minimal — 90% of mine test 4700 - 4850 range 4.2v — 2.9 v —- the Opus goes to 2.9 then drops to 2.8 instantly
I have one more cell to test today. I’ll make sure to see how much is between 2.9V, and 2.5V.
Just finished the test, and it was 100mAh from 2.9V -> 2.5V.
This cell came in at 4893 at 1A.
Cell #1: 4841
Cell #2: 4833
Cell #3: 4893
I think I’ll order more.
I’d like to see what they can do.
In case everyone’s wondering, I heard from someone at Vapcell that T50s wil not be restocked 
if you want the best high capacity 21700, try to find some Samsung 50S.
Havok —— Thanks for that information —— for 100mah not really worth stressing the cells ——- I’ve been playing around with solar and EV (scooters) from what I’m learning it’s much better not to charge or discharge to the limits —- even 4.15 - 3.10 will add lots of cycles — Don’t get me wrong I still like to max voltage for my extreme light testing — but in my sphere and outside the difference in lumens is minimal