18650 Batteries and (lack of) DNA200 'autofire' prevention (or 'Is Mooch a sissy')

[MagnusEunson]

AFAIK, the DNA200 does ~not~ have a configurable 'autofire' prevention. E.g. button is depressed and cut off after XXs for safety.

Given, presumably, most DNA200 users aren't going to be sitting at 40W - let's say 70W - 90W is the 'sweet spot' ..

Further given Mooch's excellent battery summary tables ..

It would seem to me the Sony VTC4 (not 5) is a 'peek dangerzone' choice and the LG HB2 or HB6 the obvious safest choices. (~I~ won't use Efest batteries ever again after two bad experiences.)

So .. my question to y'all is ..

What 18650s do you plan to use in your DNA200 at the subohm 70W - 90W range? Or is everyone going LiPo and never looking back?

Cheers, -Mags

 

[Mooch]

While the HB6 would stay at the lowest temperature, in my opinion, you can go with the VTC4's and enjoy the longer time before needing to recharge. If you have an autofire incident or malfunction it might end up quite hot but I don't think hot enough to vent. There is some safety margin in the table to account for high ambient temperatures, battery aging, etc.

I might still be a sissy though.

 

[MagnusEunson]

While the HB6 would stay at the lowest temperature, in my opinion, you can go with the VTC4's and enjoy the longer time before needing to recharge. If you have an autofire incident or malfunction it might end up quite hot but I don't think hot enough to vent. There is some safety margin in the table to account for high ambient temperatures, battery aging, etc.

The thing is about most of the 18650 DNA200s is they're ~printed~ and have notably less material strength and resilience to heat than standard casings. And getting honest information about deformation, not just plain damage, seems to be harder to come by than I'd like. I'd also rather not do a live experiment ..

.. but giving up the VTC4 will be a hard pill to swallow.

I might still be a sissy though.

When you start a few LiPo fires and *squeeeee*, make sure to YouTube it. -Mags

 

[Robert Cromwell]

I have always had concerns about using 3D printed materials in a device that gets hot. Isn't the printed material pretty much hot glue? Which remelts very nicely?

 

[MagnusEunson]

I have always had concerns about using 3D printed materials in a device that gets hot. Isn't the printed material pretty much hot glue? Which remelts very nicely?

There are a ton of 3D printing options but the two being used on the current crop of 18650 DNA200s are:

http://www.shapeways.com/rrstatic/material_docs/mds-strongflex.pdf

https://www.shapeways.com/rrstatic/material_docs/mds-alumide.pdf

They're not terrible bad but some of @Mooch 's battery data shows temperatures that could get to the softening levels of some of the materials. Not generally but I don't want an unexpected venting to also destroy the mod permanently.

-Mags

 

[Eric Auer]

I think I'd rather have a mod melt than turning in to a pipe bomb.....

Eric

 

[r77r7r]

I think I'd rather have a mod melt than turning in to a pipe bomb.....

Eric

I'd like that. Simply remove the chip and 510 and pop them into another battery holder.

I think we're overdue on a modular set-up for simple folks like me. That don't care about engravings or exotic woods and such.

The local library and schools just got 3D printers...

 

[xtwosm0kesx]

Assuming i'm thinking about this correctly and given the max amps the board will EVER pull from the battery is ~23a, i dont think you have much to worry about regarding heat issues.

Using the curve of Ni200 as an example (resistance increases rapidly up to a certain point as power is applied, my .2ohm coil is at .43ohms after ~1.5 secs) the board is not likely to pull a consistent 23a even during the duration of a normal puff.

In an auto-fire scenario (zero airflow) it is even less likely to pull the full ~23a for more than a second or so, as the temp limit will almost immediately be hit and it will throttle the wattage down to essentially nothing while maintaining the set temp.

Another thing to keep in mind, the board actively monitors its temperature, so in an auto-fire scenario that somehow strained the batteries enough to get hot im left to assume the board would also overheat and shut down to protect itself WELL before you would get the required temps to melt an enclosure.

Hope that helps!

PS. The 200s temp sensor is accurate enough that if you just blow on the chip you can watch the temp fluctuate in Escribe.

 

[MagnusEunson]

Using the curve of Ni200 as an example (resistance increases rapidly up to a certain point as power is applied, my .2ohm coil is at .43ohms after ~1.5 secs) the board is not likely to pull a consistent 23a even during the duration of a normal puff.

Another thing to keep in mind, the board actively monitors its temperature, so in an auto-fire scenario that somehow strained the batteries enough to get hot im left to assume the board would also overheat and shut down to protect itself WELL before you would get the required temps to melt an enclosure.

Thanks .. I'm actually not using TC ~most~ of the time which is the origin of my concern. In TC I have no concerns at all .. I still feel I get a lot better vape off of kanthal for myself.

Regarding board temp - the two DNA200 mods I've seen up close have a good bit of frame between them and the batteries or at least as much as the battery to outside frame. So in non-TC mode the board will shutdown because of ambient temperature but I'm not sure in 18650 DNA200 mods I've seen they get the same temp exposure as in the LiPos which seem to sit the battery directly up against everything else and don't have a battery chassis.

Part of this is just paranoia - my hand is damaged enough, my desk have enough burn marks. None from vaping but don't want to add that to the mix. Thanks again, Cheers, -Mags