How trustworthy are Sofirn batteries?

How much the cell sags is absolutely consistent with continuous A rating, because both are caused by the internal resistance

But on some applications like DD a single Nichia219C you dont want a cell with low internal resistance

Most flashlight applications are benign for li-ion cells, it’s the sub-ohm vapers who are cutting edge vis-a-vis li-ions and what they can do and what punishment they can take. They torture cells and need to know the continuous numbers, not the pulse, so that they can build/plan accordingly.

Chris

And the batteries get revenge when tortured by vapers:

https://www.google.com/search?client=firefox-b-1-d&q=vape+battery+explosion

The Denver TV channel (first in the search result) Another E-cig battery explosion on camera - YouTube
says they have a database of over 300 vape battery explosions.

I’m well aware of the problems and most of them are most probably due to shoddy electronics, general manufacture, or just recycled ChiCom crap.

I’m mostly referring to ‘educated’ vapers being on the cutting edge of li-ion usage, which used to be the sole provenance of flashlight geeks.

Chris

I’ll charge up two more Sofirn 3000mAh cells and compare against the 30Q, it’ll give us a better idea.

The one I tested reached 60°C at 10A down to 2.75V. Since 60°C is the max operating temp I’d rate it at 10A max continuous.

Keep in mind when looking at this 10A test my CBA has a voltage drop of 0.05V. For my 30Q test, the battery clamp had a bad connection causing the dips at the top.

The Sofirn cell isn’t looking so good at this current. Still not bad for a cheap bundled cell.

The below is tests of the Sofirn again at 0.6A, 1A, 2.5A, 5A, 8A, 10A. AT 5A there’s a 0.02 voltage drop & 10A 0.05V.

Funtastic, would you be able test the Sofirn 3000mah against a 30Q in a FET powered flashlight? Assuming you have a suitable light and a clamp style ammeter. This is how DB tested his Sofirn battery a ways back.

I believe the amp draw he saw was about the same between the two cells. He also has an integrating sphere and measured about the same lumens. I don’t know if you have an integrating sphere, but just a comparison of the amp draw would be interesting. I’ll try and dig up his original post about it.

Well, it seems my memory was a little off. It wasn’t the black 3000mah Sofirn 18650 that DB had, it was the one before that when they had the red labels. So my suspicion that Sofirn is using a different battery might be correct. Judging by this red ones performance, maybe they should go back to it if possible. It seems great!

Below is an excerpt from his review on the Sofirn C8F from Dec 2017.

Unfortunately I don’t have a clamp meter.

I do have a TA lumen tube calibrated with maukka’s lights. I’ve already tested them with the Sofirn Q8

30Q

5020 - On
4720 - 30 Sec

Sofirn

4730 - On
4440 - 30 Sec

GA

4820 - On
4460 - 30 Sec

I do have a C8F I can test to see what single cell perform is like. From memory it’s much lower. Thinking it was around 2500 and the 30Q 3100

Must be different than DB Custom’s but it still looks the same if I unwrap it.

There’s no need for further tests. It seems obvious that Sofirn is using a different battery compared to a year ago.

That’s a shame too. I had been thinking all along they were still on par with the 30Q. :person_facepalming:
Oh well they probably saved 10 cents, but most all of us would have been willing to pay at least 50 cents more and them keep using the better battery.

Why is that concept apparently so hard to understand in China? . :slight_smile:

My SP33 loses turbo faster with the Sofirn battery compared to the Shockli for what it is worth.

That red Sofrin cell has the exact looking wrapper scheme as some XXX-Fire knockoffs that HKJ has tested in the past.

Too funny.

Chris

That’s to be expected - assuming you are comparing the Shockli 5500mah (5750mah actual) to the 5000mah Sofirn. There should not be too big of a difference, but some.

How are you measuring and how big a difference are you seeing?

my sofirn 21700 4000mAh battery gives more power in C8F and FF PL47 than sony VTC6 and samsung 30Q

I must have 4 defective 21700’s then. Ran all four through discharge/charge cycles just to make sure. I get the exact opposite on the Fireflies E07

Samsung 30Q’s, and 25r’s purchased through Liionwholesale, not Aliexpress Liitokala stores

Sorry, no measurements, but enough of a difference to notice in walks down the driveway. Both are 5500 cells. IR is about twice the Shockli if you can believe the charger.

I contacted Sofirns battery store (E-Battery store) and they told me they don’t carry a 5500mah 26650 even though there are tons of pictures and such. They said they are all 5000mah. This is quite confusing. I may need to ask Tracy at Sofirn if she knows what the situation is.

Tracy has told me their 26650 does not pull a lot of amps with a FET driver. In the SP70 prototype (70.2, FET driver and 2 x batteries) their 26650 performed about the same as a pair of Panasonic NCR18650B. That’s an old cell from 2012. So we know they aren’t good for high drain usage.

The Shockli 5500mah is quite new and is a top rate battery. I would expect it to be better than the Sofirn 26650, but not by much as far as the SP33 is concerned. It might have higher voltage sag causing the SP33 to loose turbo sooner, maybe?

The question is, is there a big enough difference in performance to justify the higher cost of the Shockli 5500mah?

Your forgetting that the E07 pulls about 20A while your C8F and PL47 pull about 10A, roughly. I got the same results as you.

What RobertB is saying is that at the higher amp draws (the 20A range), the Sofirn 4000mah seems to be having difficulty while the 30Q keeps pulling strong. It seems strange to me, but I suppose it’s possible.

Some scientific testing of the Sofirn 4000mah is needed.

https://www.google.com/search?client=firefox-b-1-d&q=chinese+"good+enough"

The Battle for China’s Good-Enough Market - Harvard Business Review

It’s hard to unlearn the “good enough” attitude toward corner-cutting quality, once it gets established.

I worry about China’s “good enough” nuclear power plant expansion.

The whole thing about switching to save $0.10 is just a theory. They may have had to switch to a different battery for other reasons.