Safety of stacked 16340 batteries

[shire]

Dear veterans

By the way my thanks for your sage advice on my last question however I have another connundrum.

I am the proud owner of a wonderful redskymod vv mark 7 mod. The thing is gorgeous. However it takes 2 stacked 16340 batteries and required a dual core cartomzer. Now my understanding is that this is the exact configuration where there is a high probability of batteries becoming unstable.

I took the precaution of ordering some imr 16340 batteries then discovered i had only a trustfire charger which appently is a dangerous configuration as well. Ive been told that this device will be fine however I understand very little about the science of thermal runaway and have read too much on these forums about the dangers of all batteries in all mods.

In short with the hardware and setup I have should I still use this mod with the knowledge that I'm 99% safe to not go off like a bottle rocket or should I decommission this device and move on?

Many Thanks
Shire

 

[Hoosier]

Actual thermal runaway should be impossible with IMR chemistry batteries. They will get warm, about 93 C if I remember right, OK very very warm, but should not get hot enough to cause violent outgassing that could lead to an explosion.

The best thing you could do is to check your batteries each time you insert them and remove them. Check for nicks in the wrapper and bulging. Check the voltage of each cell before and after charging. Avoid putting a pair in with different charged voltages. (They should measure close to 4.2 volts after charging.)

Being aware of your batteries and their condition is the best way to avoid a bad event.

 

[sailorman]

I would just add to what Hoosier said. You seem to be concerned with the charger. Any charger that will work with normal lithium-ion 3.7V batteries will work fine with IMRs. While Trustfire chargers are not the Cadillacs of the industry, there is nothing inherently wrong with them. Just be sure it charges at 4.2 volts, fits your batteries and occasionally inspect if for damage, particularly to the cord. Don't leave charged batteries in any charger overnight or for a long time after they are charged.

Once you figure out how long your batteries take to charge, it's a good idea to connect the charger to a timer and leave it plugged in. That will ensure charged batteries can't stay on-charge too long and will also eliminate wear and stress to the cord, which is the weakest link, IMO, of Trustfire chargers. If you can find one, it is also good to replace the cord with a better quality cord, from an old electric shaver for example. The two-pin configuration is commonly used in many household devices like shavers, printers, coffee machines, etc. A high quality one shouldn't be expensive or hard to find.

 

[rolygate]

No boxmod has ever exploded so in theory you don't have too many worries. They can probably vent easily enough if needed. Only metal tube mods with two cells in series (and no electronic controls) that appear on a cursory inspection to be gastight have been involved with these incidents. Whatever unit you have, though, if you are going to stack batteries in it, it would pay to ensure that gas can vent somehow.

It's worth keeping in mind that no battery now can be relied on to be what the label says - so it might say AW or Tenergy on the label but be a junk cell. Because only stacked-batt devices have ever exploded, and because your batteries could be unprotected Li-ion batteries no matter what the labels say, it's worth taking extra precautions as given above.