Help choosing 21700 battery for my Sofirn C8F

wstrachan · 2019-01-08T19:54:10.000Z

The Sofirn cell is likely a 40T but thats not confirmed. They can be had for around $10 a pair through Sofirn.

BlueSwordM · 2019-01-08T20:20:24.000Z

It’s not a Samsung 30T.

It’s Lishen 4000mAh 15A.

Lightbringer · 2019-01-08T22:20:08.000Z

Yeah, I just bought the kits and use the come-with cells. They work just fine. No complaints.

teacher · 2019-01-09T05:01:17.000Z

Lightbringer:

Yeah, I just bought the kits and use the come-with cells. They work just fine. No complaints.

I got the kit too & am pleased with the Sofirn also.

Using the Samsung 50E you’ll get a bit more run time but a little less output on Turbo.

Using the Samsung 30T you’ll get a bit less run time but a little more output on Turbo.

The Sofirn battery, as Lightbringer said…… “works just fine”. :+1:

Delta_V mentioned the Samsung 40T, I don’t have one of those; but as he said….it would be a good one. On par with the Samsung 30T, but 33% more runtime.

Lightbringer · 2019-01-09T05:05:47.000Z

Wellp, I don’t quite understand the obsession with getting, say, 2700lm instead of 2500lm, when even side-by-side few if any people would be able to positively ascertain which one is brighter.

I’d go more for runtime (absolutely quantifiable) vs a nigh-invisible improvement in brightness.

Lightbringer · 2019-01-09T05:08:00.000Z

Oh, and I got a 4pak of Sofirn 21700s from the recent sale, so I’m “invested”.

teacher · 2019-01-09T05:08:30.000Z

Yeah, same here Lightbringer…. I’m more into longer run time myself.

teacher · 2019-01-09T05:12:13.000Z

Lightbringer:

Oh, and I got a 4pak of Sofirn 21700s from the recent sale, so I’m “invested”. :laughing:

How much was that “4pak” on sale Lightbringer??
Sorry I missed that…… :person_facepalming:

Lightbringer · 2019-01-09T05:23:03.000Z

Apparently <16bux on 11-11. Hang on…

Ah, here ya go…

11.11 deal Sofirn 21700 4000 40A 2x for $10.42 Free Shipping Ali Express BudgetLightForum Deal Alerts

2x for $10.42, 4x for $16.57 with free shipping. My understanding is that this cell, which is the one they ship with the C8F v2 kit, has good capacity & performance, especially for the price. This is from Sofirn’s separate battery store. Available for another 17hrs at the time I’m posting this. I ordered four. I also decided to give Sofirn’s 900mAh 14500 a try.

11.11 deal Sofirn 21700 4000 40A 2x for $10.42 Free Shipping Ali Express BudgetLightForum Deal Alerts

Kewl, actually 15.57, ’cause there’s a coupon for a buk off if spending 12bux. Got applied automagically (thought it may’ve been for lights only, but it got applied to this, too). So, color me happy… even though I have no idea what I’ll use these in, ’cept the new C8Fs.

vs19 · 2019-01-09T22:22:08.000Z

Thanks all of you for your advices, especially hiuintahs, your post is very useful.
I think I’ll stick with Sofirm for the battery and will look for a good charger.

hiuintahs · 2019-01-09T23:09:09.000Z

Hey that’s great. I think the Samsung 40T is also a good fit. If I could easily find another Sofirn 4000mAh battery, I’d go with that too. A 50E battery should be arriving soon and will have a chance to check that out.

I ended up buying the Miboxer C4 Upgrade charger. I thought it was a good value. I posted a picture of the Sofirn 21700 in it here:
Charger for 21700 or 20700 (post #22)

RobertB · 2019-01-10T00:54:50.000Z

teacher:

Lightbringer:

Oh, and I got a 4pak of Sofirn 21700s from the recent sale, so I’m “invested”. :laughing:

How much was that “4pak” on sale Lightbringer??
Sorry I missed that…… :person_facepalming:

I have 4 of the Sofirn 21700’s I’ll sell you. $4 bucks each plus what ever 1st Class mail is. I bought them for the Fireflies E07 that pulls 20A, and they just don’t work as well as the 30T does. Brightness is a noticeable difference. But for lower drain, they are an excellent cell.

teacher · 2019-01-10T05:55:33.000Z

Lightbringer:

Apparently <16bux on 11-11. Hang on…

Ah, here ya go…

11.11 deal Sofirn 21700 4000 40A 2x for $10.42 Free Shipping Ali Express

11.11 deal Sofirn 21700 4000 40A 2x for $10.42 Free Shipping Ali Express - #4 by Lightbringer

Thanks Lightbringer, sorry for my late reply; looks like some kinda ‘deal’ is still going on. I picked up 4 for just under $16.
Again, appreciate the info & links. :+1:

Sofirn 21700

RobertB:

teacher:

Lightbringer:

Oh, and I got a 4pak of Sofirn 21700s from the recent sale, so I’m “invested”. :laughing:

How much was that “4pak” on sale Lightbringer??
Sorry I missed that…… :person_facepalming:

I have 4 of the Sofirn 21700’s I’ll sell you. $4 bucks each plus what ever 1st Class mail is. I bought them for the Fireflies E07 that pulls 20A, and they just don’t work as well as the 30T does. Brightness is a noticeable difference. But for lower drain, they are an excellent cell.

Thanks RobertB, but I ordered THESE last night after LB sene those links.
Getting em’ from you would have saved the ‘China Connection’ shipping wait though. Again, thanks anyway for the offer…. :+1:

teacher · 2019-01-10T08:41:09.000Z

Oh yeah, if anyone is looking for a good, but inexpensive; charger for their 21700 batteries. Here is a Xtar 2A single bay I can vouch for.

XTAR SC1 Li-ion Intelligent Charger

.

And if you need a good USB Wall Adapter, here you go….

XTAR USB Wall Adapter - 2.1amp Output

Brainsick67 · 2019-01-10T13:07:21.000Z

BlueSwordM:

It’s not a Samsung 30T.

It’s Lishen 4000mAh 15A.

How do you know? Ive asked Sofirn but they said irs not a Samsung 40T, the cell they say is 40Amps wich i dont believe.

hiuintahs · 2019-01-10T23:09:17.000Z

teacher:

Lightbringer:

Yeah, I just bought the kits and use the come-with cells. They work just fine. No complaints.

I got the kit too & am pleased with the Sofirn also.

Using the Samsung 50E you’ll get a bit more run time but a little less output on Turbo.

Using the Samsung 30T you’ll get a bit less run time but a little more output on Turbo.

The Sofirn battery, as Lightbringer said…… “works just fine”. :+1:

Delta_V mentioned the Samsung 40T, I don’t have one of those; but as he said….it would be a good one. On par with the Samsung 30T, but 33% more runtime.

I got me a Samsung 50E in the mail today. I charged it up along with topping off the Sofirn battery. I checked in my makeshift lightbox, the lux figure for each battery. Naturally, I expected to see a slightly lower reading with the 50E at the turbo level……………which I did.

And I expected to see the same output at the lower levels regardless of what battery was installed………….but instead what I saw was a lower level with the 50E battery at all levels. At the low level (not the moon mode……just level one), I’m getting 410 lux in my light box (about 7 lumens) with the 50E. And I’m getting 660 lux (about 11.8 lumens) with the Sofirn battery.

So I’m wondering why that is? Evidently this light is not current regulated? I guess I can be OK with it as long as I get proportionally longer run time with the 50E compared to the Sofirn battery.

hank · 2019-11-28T18:11:31.000Z

Lordy lord lord, the reviews at Ali are sooooo helpful.

“If you compare with the batteries of samsung or lji of this format, then the elastic at these batteries less longer warms the speculated ”

Just what I needed to know.

Dioda · 2019-11-28T18:28:43.000Z

I have C8F in transit. Due to probably overrated “40A continuous” Sofirn 21700 cells I ordered Shockli 21700 4550mAh (purple). Should do 22A continuous and 30A pulse. For testing purposes I also went with one LiitoKala 4000mAh. Looking forward to do some measurements.

To be honest 21700 cells I dont like ordering at all, hate to play the “whats under the wrapper” game. Most of the OEM ones have rather pricey shipping for me.

HKSJOSHUA · 2020-04-18T23:12:28.000Z

I don’t know if it is to late of a post but I ordered 2 samsung 40t batts right after ordering a sofirn C8G

patmurris · 2020-04-18T23:37:15.000Z

hiuintahs:

I got me a Samsung 50E in the mail today. I charged it up along with topping off the Sofirn battery. I checked in my makeshift lightbox, the lux figure for each battery. Naturally, I expected to see a slightly lower reading with the 50E at the turbo level……………which I did.

And I expected to see the same output at the lower levels regardless of what battery was installed………….but instead what I saw was a lower level with the 50E battery at all levels. At the low level (not the moon mode……just level one), I’m getting 410 lux in my light box (about 7 lumens) with the 50E. And I’m getting 660 lux (about 11.8 lumens) with the Sofirn battery.

So I’m wondering why that is? Evidently this light is not current regulated? I guess I can be OK with it as long as I get proportionally longer run time with the 50E compared to the Sofirn battery.

At unregulated levels the driver uses PWM to modulate the output so it makes sense. When the leds are on they are at full power so they are brighter with a high current cell.