Battery safety in mod?

[kosliev]

I'm building two tube mods, (one for me, one for a friend), safety's a big deal to me, the bottom cap+mechanical switch I've built is made in plastic, has venting holes, and the switch itself has a lock in (but is made of metal bolts springs and nuts); the cap is losely fitted in (not screwed), so if pressure builds up past what the holes can vent, the cap should just come off, but:

1- Since the cap can come off sort of easily, but also has heavy metal in it, can it potentially shoot off and become a real danger?
2- If I place the battery with the + towards the bottom of the BB, and it goes on runaway, wont it blow out from the +, and make the PV shoot towards my friend's or my face (in footage of runaway batteries, the + shot out immense pressure and the battery became a shooting rocket that flied towards the - of the battery)?

The battery is a 18650 so it does carry a great deal of energy in it

 

[DreamWithin]

Moved to Modding forum, I think you'll get more relevant hits here

 

[Baditude]

1- Since the cap can come off sort of easily, but also has heavy metal in it, can it potentially shoot off and become a real danger?

It seems you have answered your own question. Use common sense.

2- If I place the battery with the + towards the bottom of the BB, and it goes on runaway, wont it blow out from the +, and make the PV shoot towards my friend's or my face (in footage of runaway batteries, the + shot out immense pressure and the battery became a shooting rocket that flied towards the - of the battery)?

The battery is a 18650 so it does carry a great deal of energy in it

IMR battery after thermal runaway


When batteries vent in thermal runaway, they do tend to vent at the positive end of the battery. However, batteries are extremely unpredictable.

My main concern is for you to use only an IMR Li-Mn battery. These are safer chemistry batteries than protected ICR Li-ion batteries. It is the ICR chemistry batteries which are most likely to explode and vent flames. IMR batteries may vent, but do so less violently.

Battery Basics for Mods: IMR or Protected?

Rechargeable Batteries

Deeper Understanding of Mod Batteries


This is more a mod issue than a battery issue. There is a modding forum on ECF here: http://www.e-cigarette-forum.com/forum/modding-forum/

 

[Dampmaskin]

My 2 cents: If the cap is loosely fitted, it will come off with little pressure. If it comes off with little pressure, the velocity will be low.

 

[Visus]

Practice safe technique and there is almost no need to worry.
You do know you can buy a mech for 8 bucks from madvapes
Or 6 bucks from fasttech
If you built it right they wont be any safer or dangerous; that battery will do what you make it do for the most part, there are exceptions of course.

Sweeeeeet mod

 

[kosliev]

Common sense, I've never had a battery runaway so I don't have any idea how that works, maybe having no vent holes in the cap is better so the initial gas pushes it out, rather than having it vent, risking to not push the cap off, and then shooting it when the battery pops.

and yeah, I'm only gonna use IMR (purple efest 18650 3100mah), but its still a ....load of energy and there is still lithium involved and high pressre

 

[Alexander Mundy]

A metal tube mod that has a battery connection at the bottom that is using the tube for electrical connection (all of them that I am aware of) should ALWAYS have the battery inserted negative side down. The negative side of the battery is also the case of the battery so if you get a rip or worn spot in the plastic on the side of the battery the tube will be touching the negative. Inserted with the positive down this would cause a dead short.

 

[kosliev]

Correct, however my tube has a 23mm diameter, I can fit a 18650 and a plastic sheet or tube to avoid that altogether, another thing to consider is that if the battery goes in runaway, and the gas vents from the top, it will push out towards the cap, ejecting itself.

Theres a number of possible ways to go about this, but to have a good idea I would have to sacrifice some 10 18650 by having them go in runaway and test.

I'm somewhat surprised that after 2 years that I've been absent from the vaping world, people still smoke on pipebombs with tiny venting holes that are probably gonna get clogged by the innards of the battery once its time to do their job, what I had thought initially was a mod that "extend itself" during venting but the cap doesnt come off (think like a pistol rail kicking back once the clip's empty if enough internal pressure is reached).

Thats far and beyond what i'm capable of building though