Некоторое количество интересной и полезной информации по 18650 и др.
Battery chemistry FINALLY explained
18650 vs 18650B etc.
What is the difference in 18650 and 18650B.
Plan to use in Convoy S2+.
Is there a valid difference in brands?
Looking for long(ish) run time. Used for tracking and can take 2-4 hrs.
Well, specifically, the 18650 denotes a li-ion cell that is 18mm wide, 65mm long and 0 means cylindrical (or as some state, rechargeable.)
They are normally a 3.6v/3.7v nominal (~50% charged) and charge up to 4.20v hot off the charger.
Panasonic is a manufacturer of 18650s and their progression in development was the NCR18650, which was a lithium-cobalt based cell (ICR) and 2900mAh in capacity. Next up, was the NCR18650A, which had less cobalt and was 3100mAh in capacity. Then they moved to the NCR18650B, which was 3400mAh and lastly, we have their NCR18650G, which eked out 3600mAh.
Other manufacturers like Sanyo (now owned by Panasonic,) Sony, LG and Samsung all make 18650s and have their own model numbers.
The chemistries have changed to hybrids, using all sorts of metals/chemicals. It used to be that you could have high current handling and lower capacities (IMR: usually for tool packs,) or you could have higher capacities and lower current handling: the NCR18650A/B.
Now with the hybrids, we have something like the Sanyo-Panasonic NCR18650GA, which has both 3500mAh of capacity (pretty high) AND higher current handling (10A,) so we get the best of both worlds right now.
Still, if you need really high current handling--15A-30A, we have 18650s like the Samsung 30Q, 25S, the Sony VTC-5, 5A and 6. LG makes some cells capable of 15A+ (HG/HE 2,) so look to that brand.
The above comprise the Big 5 for 18650s and are to be sought after. These cells all come from their respective factories with flat tops (vs. button tops) and without any added protection circuits (PCBs,) so if you see either of those, they've been added by a 3rd party vendor.
Protected vs unprotected
I used to push protected cells (“what can it hurt?”), but now I only get unprotected.
Most doodads worth anything will have their own built-in protection and not let you drain the cells too far before cutting off.
Protection circuits have parasitic drain — small, but there — that will eventually drain your cells just sitting around doing nothing, especially if you already drained them in a light without recharging them.
Most chargers probably won’t overcharge your cells, and this is maybe the only extra bit of protection where protection circuits might be better as a “just in case” level of defense.
Protection circuits will kill off high drain rates, so for whether high-drain lights, vaping equipment, etc., no protection is the norm.
The sense-strip on protected cells means the cell has to be double-wrapped, even if only a strip of kapton tape, so it will be thicker and possibly not fit into a light whose tube is marginal. Also, protected cells will be longer, and also possibly not fit.
Protected cells usually have button-tops, and some lights just won’t take flat-top cells, period, so you’d need to install your own button-tops, use a solder-blob, or use (gaaah!) small magnets.
So, all things in balance, I get unprotected cells, period.