Those are great cells.
I acquired an identical one from Callie's, and it allows for more current in my Direct Drive SST90 than my AW IMRs by over a quarter Amp. (~280mA)
I will slowly but surely be replacing all of my IMR 18650s with these.
A very good cell at a fair price is the Sanyo-based Solarforce 2400 protected 18650. The wrap is a bit brittle, however.
no but I think callie's sells them re-wrapped w/ protection. They are safer chemistry cathode, despite saying li-ion on the side, so for my purposes, the protection isn't relevant (I don't drain my cells to where protection trips....on purpose anyway).
Yep
I'll also back the Sanyo-based Solarforce 2400mah. Indeed, the wrap is brittle, which is the only downfall. Otherwise they are quite the performer for the price. They seem to match my XTAR 2600's.
What about cycle life & shelf life? I’d guess they would be quite high due to low initial internal resistance (isn’t it’s increase the cause of cell degradation?)
I hate to spend $50 on 6 batteries, but I may not have much choice
These were, AFAIK, designed for use in high-draw rechargeable power tools. Since both criteria are important design considerations, I would infer that both would be excellent - why bother changing chemistry otherwise? Pricing is similar, if not greater, than common lithium-ion cells.
The sample that I own has performed above expectations over the last 9+ months.
can't say for sure, only a few cycles
but, I would assume that a cell that can do 10A discharge (at very close to stated capacity!) will handle 3 and 4A discharge for a lot longer than cells that are struggling when they do that? Now...that's not very scientific...but it made me feel better about spending $9 on a battery lol
the other thing to note w/ this cell, is that for some lights, it has more usable capacity than the mah alone implies - check out the tests/graphs done on this cell, and the voltage level that it maintains during discharge...a couple members (hkj and mitro?) were kind enough to share data of some thorough testing.
..I'd also guess that it would charge faster at amp same rate due to more time spent in CC phase and less in CV phase?
(I might be wrong on this one though, correct med if needed please ;Ь)
I vaguely recall the charge rate spec is lower than similar cells - but someone probably knows what it is off hand...
I use 1A setting on my hobby charger, or an xtar mp1
Surely is offtopic, but whats a cheap way to test the capacity of a battery?
HKJ has a roundup of 18650 batteries at CPF with a lot of good data. He's not finished yet, but there is a lot of good info there.
http://www.candlepowerforums.com/vb/showthread.php?330236
Cheap way to measure capacity? You can get a rough estimate by measuring current draw in milliamps on a flashlight at a regular intervals like 10 minutes until you get down to whatever cutoff voltage you want. 10 minutes is 1/6th of an hour, so you total all of the current readings and divide by 6 to get mAh. You will have to average the initial and final reading or you will have one reading too many.
If you get a hobby charger you can do it, but mine will only do a maximum discharge rate of 1000 mA.
If I needed more 18650 = Sanyo
I know there not protected , but Im ok with that ..
There were some really nice prices a little while ago on the 2600 ..
http://www.intl-outdoor.com/sanyo-18650-2600mah-liion-battery-p-135.html
I have some of the Trustfire 3000 that I bought a few months ago. They seem to be good and hold more capacity than my other less expensive batteries. I just ordered 8 more from MF the other day. I hadn't heard that some are having problems with newer batches. Hope mine will be ok.
I recently bought some 2900mah unprotected panasonic NCRs from focalprice. I think they are ~$7.50 shipped. If you buy more than 3, then it starts getting cheaper. I just received it the other day... running some tests on them and will start another thread and report back when done. But here are a few quick figures for you:
-arrive at ~3.64V
-charged up to ~4.16V
-Discharged at 200ma, until it reaches 3.0V (low cut off for my acucell 6). Gave 2749mah. Resting voltage after test 3.19V (this means there's still juice left in the battery, as the ncr18650 can be discharged to 2.5/2.75V).
My only concern with these batteries are the middle of the battery bulges out very slightly. Probably not a good sign?
Could you take some photos?
I don't think it will show up very well on photos.. it's hard to see, more a tactile thing for me. I'll try post some photos when I get a chance anyway
Try using a caliper to measure the difference , diameter towards the ends and diameter on the bump. Also you can check later if the "bump" diameter has increase with use or not.
Has anyone dealt with these MarsFire branded "Sanyo" 18650's from manafont? I am tempted to order one as they are so cheap for protected sanyo's.