Recently I just bought a Convoy S2+ as an EDC light. I also bought a couple of 18650s for it. 1 is always inside my flashlight, the other 2 (Sony VTC6 3000mAH) always inside a pelican 1010 box.
I understand 18650s are prone to explosion or fire if not taken care of properly so I want to know what to do and what not to, especially now im carrying a few more extra batteries inside my bag. Im just scared that it might just explode suddenly while I commute on the train inside my messenger bag lol!
As long as they are well wrapped and without the danger of hitting each other or anything sharp, then they should be fine. A small plastic box would be the best way of transporting them. none of my boxes have any extra cushioning or protection and nothing has happened so far.
18650s are relatively safe. Don't short circuit. Don't over charge, Don't over discharge and Don't over heat the cells and you are probably safe.
The risk is usually while charging and as long as you use a good charger I see no problem. If you still worrying get a charger with a thermal protection feature and you may also use a Lipo fire resistance bag but I see no reason why
Round Li ion cells are pretty safe. The issue is when you abuse them, like was mentioned. Over charging is really bad and more often than not the cell will just die not explode if overcharged since good quality cells have an internal safety fuse that trips when they get overheated or overcharged. If something happens and the fuse doesn’t trip in time the cell will run away thermally, and in that case they usually vent out the top and don’t explode. Shorts are also bad. Keep the wrap in good condition since the entire outside of the cell is the negative terminal and it’s easy to short it if you accidentally touch something metal against the side and top. Trust me, a short on a high drain cell is not good. Lipo cells is something else. They can be really dangerous if you abuse them.
explosions are usually caused by dead shorts, super high currents (same thing really), physical damage, or trying to charge when the cell is over-discharged
even then it might take a super-cell to explode
a high drain cell
again this stuff is more common with what vapers are trying to do
About a month ago, before I started updating my flashlight collection, I noted that there were 96 18650 cells in my house in various devices. They are in power tool batteries, robot vacuums, power bricks, laptops, etc. 18650s are not particularly dangerous. If they were, they wouldn’t be in so many consumer devices that aren’t particularly well taken care of.
All Li-ion have a lot of energy in a small package, and therein lies the danger. Lithium Cobalt cells like your VTC6 are a special animal. LiCo cells that are over discharged below 2.5V can form crystals in their liquid electrolyte, which may cause a short, and when placed back on a charger, may cause a fire or explode. This is why you will often see and only see LiCo aka ICR cells with a protection circuit, to prevent the cell from dropping below 2.5V. Your VTC6 likely doesn’t have a protection circuit, so you must be vigilant to prevent it from dropping below 2.5V, and vigilant to always have a good idea of the cell’s state of charge. If it does drop below 2.5V, do not attempt to recharge it, better to recycle it in a battery drop at your nearest hardware store.
Further explanation by the inventor of Li-ion batteries:
Biscotti firmware has LVP, older 3/5 firmware only has a warning but severe overdischarge will take a while with a linear driver, I was told there is a small parasitic drain even when below the LED’s Vf.
The VTC6 like most modern cells is hybrid chemistry, NMC. Check this video by Mooch for an explanation about chemistries. Dropping below 2.5V is still a bad idea nevertheless.
Thank you for the correction… I made a poor assumption. For some reason my VTC4 cells are labeled ICR, when INR would be more correct. That’s annoying.