I understand lol
So youre doing exactly what Im talking about. You’re charging the 3500mah at 0.29C and you’re charging the 2000mah at 0.5C. Like I said, at the top end of capacity for a format a lower C rate is generally preferred.
Ex) Max rated charges:
Samsung 20R/S: 4A, 2C
Samsung 35E: 2A, 0.5C
Molicel P28A: 6A, 2.1C
Molicel M35A: 1.7A, 0.5C
Samsung 40T: 6A, 1.5C
Samsung 50S: 6A, 1.2C
But what doe the C mean. That is what I was trying to clarify…and what confused ME, when I read your first post on this.
Too many damn many "C"s being used without clarity. If you would have said Charge rate or charge current… it would have been clear… especially as we were originally talking about C being capacity…
Not really…really being critical, just striving for clarity. Especially for say, the OP, who asked the question because he just didn’t know the subject.
But no sweat, maybe it is only me that is confused about such things… or maybe my technical writing background biting me in the butt…
Bottom line, we obviously agree on charging strategies… so there is that !!
I’m all for being nice to LiIon batteries (e.g. I keep my tablet/phone between 35 and 80% state of charge whenever possible) but I don’t want to wait forever when charging, so my strategy is:
-high discharge rate 21700s and 18650s (Sony VTC6, Molicel P45B, Samsung 40T): 2A
-Sanyo NCR18650GA and the like: 1A
-Eneloop AA: 1A
-Eneloop AAA: 0.5A
For me this strikes an acceptable balance between convenience and longevity.
“here, here”. Things do get (unnecessarily) confusing sometimes.
One of the worst trends in recent years has been the compulsion some have to use any abbreviation for anything without regard to custom / accepted standards, and re-use them for something different without a thought. Yes, industry norm is that ‘C’ denotes capacity in this context. ‘I’ is the long-standard abbreviation for ‘current’, and I’m not aware of a standard abbreviation for ‘charge’ or ‘charging’, unless it’s ‘chg’, which would at least eliminate the ambiguity. The increasing ‘laziness’ in spoken English is problematic.
I agree. When I send a text message, I use proper grammar. Now, I’m not a grammar expert but I always try to make sure that I am using proper punctuation. I also use the actual word or phrase and the only abbreviation that I use is lol.
I was taught that it was OK to use abbreviations or acronyms only if they were defined in common language the first time used in a document i,e Capacity (C). Of course when using such terms in a formula, each term should be individually defined… But yeah, everyone makes up their own abbreviations, contractions, acronyms and never defines them. I think that quite often their whole message is lost because many readers just have no clue what they are referring to.
Oh well, I guess the thought is saving a couple of keystrokes is worth not being understood.
Off of soapbox now !!
So I just did my 2nd cycle of my new vapcell N36 3650mAh batteries and one was 3293mAh’s and the other was 3297mAh’s.
Is this acceptable for new batteries or should I ask for another pair of batteries? It’s 90.22% & 90.33% of claimed mA’s.
Did you run the test on both of your chargers?
It could be charger dependent. I see reviews where people have gotten more out of the cells, but test conditions aren’t mentioned.
I am usually OK with 90%+ of rated capacity… and overjoyed when I get higher. I suppose you could ask about replacement. Where did you buy them?
Yes, on my opus BT C3400 I got the above mentioned numbers and on my liitokala lii-m4s I got 3273mAh’s & 3282mAh’s. Maybe I’m expecting to much because of how well my MJ1 & Panasonic/sanyo 18650 batteries did. All 6 of them were above the 3500mAh’s by 5%-10%.
I think I will see about a discount on another order but I didn’t order them from the official vapcell store on Ali express. I didn’t know they had one and I got them from another store. I can use them as back ups to my 3500 batteries. Returning them and waiting for new ones would be a long process.
I can attest the Fenix ARE-D1 works at 2A (albeit I usually charge my batts at a lower rate).
Does your Fenix discharge at 2 amps for the capacity test?
Though if you subscribe to the 0.1 C discharge rate for most of the cells we deal with (other than torture testing) 2 A is overkill.
Which why it is so nice to have Mooch and HJK to do this for us.
@ToddZiegler1024 This could be part of the discrepancy you are seeing. If the factory tests discharge at a different rate (maybe 0.5 A) the numbers will be considerably different. But the cells you tested are not really that bad at all.
I personally don’t own a Fenix charger and not one that does a discharge.
I have a LaCrosse BC-700 that does a discharge, but that’s only NiMH, same with my Maha C900.
For discharging Li-Ions, I have both the Opus BC-3400 v. 2.2 and the Opus BC-3400 v. 3.1.
Both only discharge a 1A for all slots.
Chris
Sorry for the confusion… I quoted your comment to show you were talking about discharge not charge level. I was asking @dmenezes if his Fenix Fenix ARE-D1could discharge at 2 amps. BUT, when I checked the link, it seems that it doesn’t enable capacity testing at all. So a dumb question after all.
I can see how it was confusing… 
Looks like I confused myself…
No problem, as I think that this thread is already a bit dwanky!
The Fenix charger quoted, can only ‘charge’ at 2A.
I don’t know what the discharge current is, but it’s probably not 2A.
Chris
The ARE-D1 indeed does not have capacity testing, but it does operate as a powerbank so it can discharge the cell into something else, and reputedly does so at up to 2A (depending on how much that ‘something else’ will draw), but during discharge it shows only the cell voltage, so it’s not good for capacity testing.
When doing discharge / capacity tests, also keep in mind that in addition to discharging rate, discharge cutoff voltage is also a factor in capacity results. According to HKJ, some manufacturers use 2.5V. I’ve seen Vapcell data sheets which show that they use 2.5. I believe my BTC3100 uses 2.8/2.9. HKJ uses 2.8 for his testing. I believe a later version Opus (perhaps the BTC3400 uses a higher cutoff than the 3100 (CG would likely know what that is). The MC3000 (SkyRC) defaults to 3.0V, although I’ve set mine for 2.8V.
Got it. I knew I was just unnecessarily complicating things lol. Should’ve just left it. Was splitting hairs anyways.
I want to get a constant current electronic load myself. Not for capacity testing. They’re expensive though. I wonder if those cheap AliExpress ones are any good. It’s just a fet on a heatsink with a fan. Exactly the way most chargers would discharge. Just a bigger heatsink. Maybe not worth it.
I changed the discharge rate to 500mAh’s and I got much better numbers, 3655mAh’s for one and 3650mAh’s for the other.
I’m very glad that I decided to change the discharge rate and do a 3rd test because I didn’t want to mess with exchanging or returning the batteries.
I’m still waiting for one vapcell F52 21700 from Ali express and two F56 21700 batteries from Liion.
These batteries will complete my battery upgrades for each one of my childrens emergency bag flashlights.
I would have never known the conditions of my batteries if I had not joined this forum.
FYI, in my experience this is a constant with all kinds of batteries: higher discharge currents (in A) means less total capacity (in Ah). I learned about that first in the good (not) old days of lead-acid batteries, and there was even a fancy name and formula for it: Peukert Law.
I wasn’t sure the fancy math held for Lithium-rechargeable batteries, but some searching seems to indicate they do, at least for LiFePO4: https://battlebornbatteries.com/peukert-effect
Usually the manufacturer’s datasheet gives the current their battery should be discharged at to find its nominal capacity, and it’s usually a very low current relative to the battery’s maximum (eg, for the LG MJ1 INR18650, the “standard” 0.2C = 680mAh, vs a max of 10A ).
This is something I should be saving in my phone for reference. I’m slowly catching on but I need a lot more studying.