KeroZen
Chronic vapaholic
Modnote: This is an informative cross-post from the Nomad thread
No, I'm saying these battery chemistries (variants of Lithium-Ion) are unsafe by nature. You should always be careful during handling, use, storage and charge.
That's the price to pay if we want power and it's the best available today. Next technology might be better, it's supposedly around the corner... but it's been quite some years already and we're still waiting, not unlike nuclear fusion...
Note that it will likely be a revolution and the stakes are very high (notably electric cars becoming mainstream, so there's a lot of money at play, both to be made and to be lost, by oil companies and producing countries, but let's not get political here!)
Mass-produced vapes using 18650's should be fine. Their contacts are precision machined by robots and are very smooth. They also have to get through the whole certification process to be able to enter the US and EU markets. So for instance your Tubo being based on the joyetech evic VTC mini, or other Chinese-made vapes like the X-Max etc should be ok (note that I always insert the positive side first in my evic and other mods such that it's the negative side that grinds on the contact though)
It also greatly depends on how the contact is designed. If it's a door or something you screw it's less problematic than something that slides and grinds.
For your other vapes: I always have the negative terminal facing up in my Milaana. Again grinding on the negative terminal is completely safe, it's a solid flat piece of stainless steel, it's the other side that is delicate. In the MVT the door slightly grinds on the positive, so I took the habit of pushing the cell down with the tip of one finger while sliding the door. The pressure is small and the contact is round but better be safe than sorry (I told Dave to consider reversing the cell polarity, but as is you can't just insert it backwards as the MVT touch switch is polarity sensitive)
Just watch your cell wraps closely and if they get damaged at the top (anywhere else is harmless) bring them to a vape shop to get them rewrapped (or order a wrap kit from the place you got your cells from, it's easy to do)
Yes that's a possibility, but why not eliminate the risk altogether by inserting the cell the other way round?
In its current form the cell can go both ways. My remark about the beefy ground is just the normal practice as everything converges to that part, but here the circuit is super trivial and only a single path flows through. I can't comment on your remark about having the switch high side or low side, maybe it makes a difference in practice, I don't know. With MOSFETs it makes a clear difference but in a mechanical-mod configuration like this I'm unsure.
It's simple, look at this picture:
The entire cell shell (the can) is negative, meaning the bottom, the sides and up to that shiny rounded lip (the upper-most that is, including the "rings" below) Then the brown part is insulation and the raised center post is the positive terminal.
When the cell is wrapped it also has an (usually white but can be black) extra insulation ring above the brown part. This ring can get dislodged when the wrap is damaged, as it's just floating and held "sandwiched" by the wrap.
All you have to do to short the cell is connect the lip to the center post, and they are a few mm apart in a straight line. A key could be enough, like in your pocket as you said (hence the need to always carry them in the provided plastic case. If you don't have those, no excuse they are worth cents only on aliexpress!)
Indeed when you short the cell it heats first and does not necessarily enter the thermal runaway mode. When it gets past 120°C or something it will start venting. Normally only hot gas and nasty boiling chemicals (awful smell) and in the worst case it can even catch fire (less likely with IMR/INR than the so called "Li-Po" soft pouch ones as found in cell phones and remote control stuff)
No, I'm saying these battery chemistries (variants of Lithium-Ion) are unsafe by nature. You should always be careful during handling, use, storage and charge.
That's the price to pay if we want power and it's the best available today. Next technology might be better, it's supposedly around the corner... but it's been quite some years already and we're still waiting, not unlike nuclear fusion...
Note that it will likely be a revolution and the stakes are very high (notably electric cars becoming mainstream, so there's a lot of money at play, both to be made and to be lost, by oil companies and producing countries, but let's not get political here!)
Mass-produced vapes using 18650's should be fine. Their contacts are precision machined by robots and are very smooth. They also have to get through the whole certification process to be able to enter the US and EU markets. So for instance your Tubo being based on the joyetech evic VTC mini, or other Chinese-made vapes like the X-Max etc should be ok (note that I always insert the positive side first in my evic and other mods such that it's the negative side that grinds on the contact though)
It also greatly depends on how the contact is designed. If it's a door or something you screw it's less problematic than something that slides and grinds.
For your other vapes: I always have the negative terminal facing up in my Milaana. Again grinding on the negative terminal is completely safe, it's a solid flat piece of stainless steel, it's the other side that is delicate. In the MVT the door slightly grinds on the positive, so I took the habit of pushing the cell down with the tip of one finger while sliding the door. The pressure is small and the contact is round but better be safe than sorry (I told Dave to consider reversing the cell polarity, but as is you can't just insert it backwards as the MVT touch switch is polarity sensitive)
Just watch your cell wraps closely and if they get damaged at the top (anywhere else is harmless) bring them to a vape shop to get them rewrapped (or order a wrap kit from the place you got your cells from, it's easy to do)
Yes that's a possibility, but why not eliminate the risk altogether by inserting the cell the other way round?
In its current form the cell can go both ways. My remark about the beefy ground is just the normal practice as everything converges to that part, but here the circuit is super trivial and only a single path flows through. I can't comment on your remark about having the switch high side or low side, maybe it makes a difference in practice, I don't know. With MOSFETs it makes a clear difference but in a mechanical-mod configuration like this I'm unsure.
It's simple, look at this picture:
The entire cell shell (the can) is negative, meaning the bottom, the sides and up to that shiny rounded lip (the upper-most that is, including the "rings" below) Then the brown part is insulation and the raised center post is the positive terminal.
When the cell is wrapped it also has an (usually white but can be black) extra insulation ring above the brown part. This ring can get dislodged when the wrap is damaged, as it's just floating and held "sandwiched" by the wrap.
All you have to do to short the cell is connect the lip to the center post, and they are a few mm apart in a straight line. A key could be enough, like in your pocket as you said (hence the need to always carry them in the provided plastic case. If you don't have those, no excuse they are worth cents only on aliexpress!)
Indeed when you short the cell it heats first and does not necessarily enter the thermal runaway mode. When it gets past 120°C or something it will start venting. Normally only hot gas and nasty boiling chemicals (awful smell) and in the worst case it can even catch fire (less likely with IMR/INR than the so called "Li-Po" soft pouch ones as found in cell phones and remote control stuff)
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