I think ICR chemistry gets too much of a bad rep. If you look at the spec sheet for something like a Samsung ICR18650 26F (like you’d find in a laptop battery pull), they’re designed to be subjected to some pretty severe torture tests without exploding or catching fire. They’ll take short-circuiting, they’ll take being baked in an oven, etc.
What they might do under those extremes, is vent. But that’s what they’re designed to do, when subjected to high internal pressure from heat. It will ruin the battery, but it should be “safe”.
I think ICR gets a bad rep because of no-name cells, or Ultrafire or Trustfire brands. They aren’t properly designed, and are not safe. But you very likely will not find those crap cells in genuine laptop battery packs.
You can buy new Samsung 26F cells very cheaply. They’re about half the price of the more expensive INR chemistry, or higher capacity cells. Treat them sensibly, and they’re perfectly safe.
That said, I wouldn’t buy “used” cells from someone, regardless of the brand. You just don’t know if they were ever discharged to an unsafe level or something.
I use cells from laptop pulls in some of my high-drain lights, and they work fine. The light isn’t quite as bright using them, compared to high-drain batteries, but they don’t get hot or anything like that. I keep them fully charged, which causes cells to lose capacity, but they’re laptop batteries so I don’t really care. That’s why I use them in my lights that I don’t use frequently. I treat my “good” cells a little better.
Think of solar cells, with those “solder traces” on the face. That’s not what they are, but they’re what collect current from the active area.
You can put only a few of those strips on the solar-cell to maximise surface area to get the most current. But they’d be few and thin, and wouldn’t be able to carry out much current.
Or, you can put lots of ’em on there and make them thicker, to be able to carry more current, but then you’re covering up more of the active surface and decreasing how much current can be produced.
So in a Li cell, you can make it more reactive and be able to stuff more electrons in there for higher capacity, but there’s a limit as to how fast they can drain, OR, you can optimise it for current-drain and it won’t have as much capacity.
The difference between 3400mAH and 2800mAH isn’t all that terrible, not if one can only safely drain at 5A-6A and the other at 30A or more. Just use the right tool for the job.
So for my EDC lights that aren’t too high-strung, panny-Bs are fine. In a Q8 or something, I’ll stick some 30Qs in there. Ain’t rocket surgery or anything.
Too many erroneous presumptions lying around in this thread…
Loaded battery voltage is always lower than unloaded, especially for li-ion at end of discharge. Check this article: How far can LiIon be discharged?
Most common IC found in cell protection boards is the DW01A, with a typical overdischarge detection voltage of 2.4±0.1V.
The usual cheap (or not) flashlights with unsophisticated linear or MOSFET drivers cannot boost voltage, this means overdischarging a cell in them requires you to leave the flashlight on and unattended for long enough for it to happen. This may be a nice while because emitter current tapers down fast once voltage gets below ≈3V, and there you'll certainly notice the loss in brightness (or you should).
However, take care with those cheap AA/14500 or AAA/10440 torches. Stick to quality flashlights with low voltage warning or cut-off here because due to the need to operate with AA/AAAs they use boost drivers and if you allow it they can ruin your li-ion/LiFePO4 14500/10440s fast.
And fellows, please stop with the usual ICR vs INR vs IMR whatevers. Actual cell chemistry usually has little to nothing to do with whatever is stamped on the wrap.
Cheers :-)
Originally posted on Fri, 12/15/2017 - 01:27; typo fix.
Those Samsung 28As, like a lot of similar cells, are specced for 2C max discharge, which works out to 5.8A. That is plenty for a lot of lights.
The biggest issue is that they need to be charged to 4.3v to get to full capacity. But the flip side of that is that if you charge to 4.2, you’ll probably get a lot of life out of them.
Only a few years ago, laptop pulls were often the most economical option, and plenty of people used them for flashlights without regret or incident. Some still do.
These days I don’t think laptop cells are necessarily worth it. But so far, I’ve been passing on deals for cells like the 30Q because I have lots of laptop pulls (and even more unopened laptop packs) that work just fine for most purposes.
This guy claims that lithium-ion cells are usually safe, even when reverse-charged (a little bit). Is he insane, or have the dangers of low-voltage been overstated?
I’ve also read about using the same set of batteries for a multi-battery flashlight. And also let them age at the same time.
But I’d also like to ask what kind of “devastating consequences” can be expected for unbalanced/unmatched cells?
Another question, let’s assuming I have a bunch of batteries (eg. all LG HG2s) that got mixed up with regards to their aging, would it be ok if I try to use an analyzing charger and sort those that have similar capacity, then also check that these similar-capacity HG2s have internal resistance (eg. MC3000 reading) close to each other. Will that be sort of OK now to use as a set in the multi-battery flashlight?
d_t_a, for “devastating consequences” they usually refer to cell polarity reversal, which can happen when cells or sets of cells in series are dissimilar enough for a stage to get reversed.
With regards to your HG2 cells, your approach makes sense. For internal resistance determination I'd take various measurements per cell and average them out.
Thanks for all input guys. I have not been on computer so hence my replies are very limited. Please keep on adding any information from your personal experiences. I really want to make sure I do not make mistakes. The reason I ask all these questions. Thanks again.
Hi.
I have ordered a big 5W laser and I have been told by the manufacturer that I have to use only protected 18650 batteries.(I need 2 of them).
Because I buy batteries from NKON.nl,I have to choose from what Nkon has,ie the following. https://eu.nkon.nl/rechargeable/18650-size/lithium—-protection-circuit/protected.html .
Can you please suggest what you think is better?
All of these cells are rewraps from the main manufacturers. Can't go wrong with any of them.
Vapcell Cassiel did not provide a link to what she suggested. Hard sell this way. This and that are proper debloated/cleaned links to Vapcell AliExpress site (all the rubbish to the right side of the question mark removed, question mark included).
First you will have to measure (or ask the manufacturer) the inside of the battery tube carefully to find the largest size that will fit. Then you find the highest capacity 18650 battery smaller than that. 5W is a low power for 18650 batteries so you don’t need high drain batteries. In an ideal world manufacturers would design for 19x70mm so every possible protected cell would fit but we don’t live in an ideal world.
The Keeppower 3500mah Botton top would be the best choice from NKON if it fits, otherwise the 2900mah model seems to be smaller.
Don’t forget to get proper protection glasses for the laser frequency for everyone in the same room you use the laser, if you don’t want anyone to get blinded by accident. A 5W laser is not a toy .
Wellp, problem is these are not protected batteries. When layman people asks for “protected batteries” they usually refer to cells with built-in battery management system, usually consisting in a DW01A protection integrated circuit plus at least 2 × 8205A dual MOSFETs.
EnerPower and Imalent batteries are Samsung 30Q cells with an improved protection board featuring 4x 8205A dual MOSFETs. No one said that to me, but the discharge voltage drop figures match (4x 8205A dual MOSFETs in parallel have ≈7mΩ of resistance when not warm).
The above products is what people looks for when they ask for protected batteries. DW01A protection boards are installed over the cell cathode and powered with a thin nickel strip from anode to cathode. Cells are then double wrapped.
Some cells in the market use protection circuits over the cell anode. The above Lumintop and MecArmy cells do it this way, with the addition of USB charging.
Protection circuits over the cell anode are safer, they avoid potential short circuits due to punctured or torn wraps.
I think that if you are going to be semi-serious about lights… future proof yourself with the MiBoxer c4-12 charger…
And myself, I just picked up 24 Sanyo 18650GA cells from Illumn.com 3500mah capacity and rated for 10 amps
tell us what light you plan to use Unprotected cells in
Determine if the light you want to use Unprotected Cells in, has built in OverDischargeProtection
Determine if the light you want to use Unprotected Cells in, has a built in Battery Level indicator.
stay away from multi battery lights
Keep UnProtected Batteries away from lights with NoBuiltIn OverDischargeProtection
IF you are going to use LiIon, obtain a device capable of telling you the battery voltage, so you can avoid overdischarging.
If you use Turbo, and it stops working, dont turn it on again until you recharge the battery. Do not fire turbo over and over again, that is a good way to get into trouble.
The danger of LiIon is that IF they have been overdischarged, they Might start a fire during recharging.
Put charging batteries in a fireproof location, and do not leave unattended, in case they start to get Hot and Vent with Fire…
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