Hello, BLF people. First post here, after reading around quite a bit. I've picked up a few Sofirn lights in the past 8 months or so, including the SC21 and SP10v3 for my kids, BLF LT1 (awesome, thanks DBSAR, ToyKeeper and Sofirn!), SP35, SP10Pro (my new EDC after a Thrunite T10), and D25LR.
Anyhow, I'm a tinkerer and geek out a bit over battery charge, capacity, and whatnot. I found myself wondering what chemistry is in my Sofirn batteries, and digging hasn't gotten me an answer. I learned from Funtastic here that the 21700/5000mAh as of Feb 2021 is a rebranded Lishen LR2170SD, but I've been at a loss to learn the actual chemistry. The Lishen data sheet doesn't mention it. Sofirn wrote in response to my query: "I'm sorry I'm just customer service, we don't have this related data yet," and could not connect me with anyone that would have this info.
Does anyone have a source for this battery's chemistry? NMC, NCA, ICR, IMR, something else?
Hi, welcome to BLF! That’s a great bunch of lights to start with.
Maybe somebody can answer this with more authority but generally these days INR rules the roost for the best performing cells and I’d just about assume that’s what those cells are. IMR is still around and there are still current ICR cells to be found. Other than what’s printed on the wraps I’m not sure I’ve seen that info elsewhere. None of the Sofirn or Wurkkos cells I have has that on the wrapper, but we do know they’ve used some very good Lishen cells for their 18650 and 21700 the last few years. They’ve switched cells at least once but the performance stayed the same…I’ve wondered if not having the INR or whatever on their wrappers is because they don’t see a need for it or if it’s to allow them to more easily change cell models/suppliers if need be. Also, within each “chemistry” there are different tweaks and such in both the chemical contents as well as the assembly itself, but probably nobody will ever learn those details…but an INR or whatever doesn’t necessarily mean the same general performance characteristics from one model or brand to the next.
Vapcell’s rep Dennis is frequently on this forum and has several threads…you could try to PM him or ask in one of those threads. If he knows or can find out, he’s pretty transparent and forthcoming with tech info…he’s actually shared some great tidbits about various China cell manufacturers and the wholesale scene.
Whatever a cell is, it’s always the legit tests that tell us the most. HKJ has a fantastic encyclopedic website where he’s done electrical and performance tests on gajillions of cells, plus chargers and meters. Mooch from the e-cig forums also has done lots of cell tests, but he tends to focus more on higher current drains…very solid and he’s a straight shooter, but we don’t see the more granular or low current results from his work (like what most of our flashlights will be operating at other than turbo).
HKJ’s best-main-landing-page….long scroll list of tests but at the top are the various categories of cell tests and charger tests…click on them and it’ll open those pages. On the charger page, each column is sortable just like excel (no hints, just a click response). Batteries and chargers
Here’s his 18650/21700 comparator page…pick a cell from each dropdown box and then you can check or uncheck the various currents to see how those cells perform. Best thing ever. When you select cells there will also be a link for the actual individual test of those cells. Have to kind of find your way around the listed cells by brand…he hasn’t tested everything and some are quite dated now, but it’s a fantastic resource. Battery test-review 18650 comparator