Series question

[Classic vaper]

I have been using stacked series mods since 2015 almost everyday with no issues. A guy at the shop today scolded me because I put two of my single mech batteries in my stack saying " if they arent married its really dangerous". I have never paid any attention to that because I always thought that if both batteries are fully charged they fire and if they have different voltage they dont fire. Is the married thing wivestale hype or have I just been an idiot since 2015? I use .42 coils which are very safe for 30amp batts.

 

[Topwater Elvis]

Yes married cells is a real verified thing when using any multi cell vaping power device.

Same brand name, same mah, same CDR, bought & used together as a matched pair or set.
Most folks mark the cells so they can be sure matched sets stay together.

What/which 30a cells are you using?

What do you mean by .42 coils?

2 - .84Ω coils together to reach .42Ω or 2 - .42Ω coils together which would be .21Ω, or a single .42Ω coil?

 

[Classic vaper]

Yes married cells is a real verified thing when using any multi cell vaping power device.

Same brand name, same mah, same CDR, bought & used together as a matched pair or set.
Most folks mark the cells so they can be sure matched sets stay together.

What/which 30a cells are you using?

What do you mean by .42 coils?

2 - .84Ω coils together to reach .42Ω or 2 - .42Ω coils together which would be .21Ω, or a single .42Ω coil?

I am using the 30 amp Samsung 20s batts. Its a dual coil stagg clapton build at .21 per coil. I feel perfectly comfortable with throwing two batteries in a stack as long as they are the same battery and are fully charged. I mean... what could happen? It not like they will vent just because they have occasionally been used in single battery mods.

 

[Don29palms]

I am using the 30 amp Samsung 20s batts. Its a dual coil stagg clapton build at .21 per coil. I feel perfectly comfortable with throwing two batteries in a stack as long as they are the same battery and are fully charged. I mean... what could happen? It not like they will vent just because they have occasionally been used in single battery mods.

.21ohms per coil and dual coils is .105 ohms final.

Look up mooch's channel. I believe he did something referring to the married batteries thing.

 

[Punk In Drublic]

I am using the 30 amp Samsung 20s batts. Its a dual coil stagg clapton build at .21 per coil. I feel perfectly comfortable with throwing two batteries in a stack as long as they are the same battery and are fully charged. I mean... what could happen? It not like they will vent just because they have occasionally been used in single battery mods.

Venting a concern in itself, but thermal runaway can cause serious injury. And yes, it does matter. Batteries do not age at the same rate. Marrying batteries mitigates that variance. It’s not a matter of venting, but reducing risk.

Your coil comments are confusing. First post you said 0.42 ohms, now you say 0.21 ohms per coil. 2x 0.21 ohm coils in Parallel is 0.105 ohms as it was noted by @Don29palms. So the question is, what is the resistance of your build when using your stacked series mech?

 

[bombastinator]

My memory is that the issue is batteries wear. Having married cells insures that they wear at the same rate. Having two cells with very different wear levels can cause problems. To reiterate @Mooch goes into depth on this somewhere

 

[Topwater Elvis]

8.4v / .105Ω = 80a
even when the cells fall off to 3.4v each
6.8v / .105Ω = 64.7a

In a 'stacked' mechanical the voltage doubles, the CDR stays the same as that of a single cell.

I take it you haven't been confirming your resistance by use of an accurate ohms/multi meter or regulated power device?

 

[Zaryk]

I am using the 30 amp Samsung 20s batts. Its a dual coil stagg clapton build at .21 per coil. I feel perfectly comfortable with throwing two batteries in a stack as long as they are the same battery and are fully charged. I mean... what could happen? It not like they will vent just because they have occasionally been used in single battery mods.

If you are running two .21 coils, it isn't going to be .42 total. Like Don said above, it's .105 ohms. On a series mech that is somewhere around 80 amps (didn't calculate, just figuring off the top of my head) so that is stressing those 30 amp batteries out. Especially under those conditions married batteries are a must. I second the statement to look into mooch's blog on married batteries and mech use.

 

[Classic vaper]

Venting a concern in itself, but thermal runaway can cause serious injury. And yes, it does matter. Batteries do not age at the same rate. Marrying batteries mitigates that variance. It’s not a matter of venting, but reducing risk.

Your coil comments are confusing. First post you said 0.42 ohms, now you say 0.21 ohms per coil. 2x 0.21 ohm coils in Parallel is 0.105 ohms as it was noted by @Don29palms. So the question is, what is the resistance of your build when using your stacked series mech?

It is a .42 build on a ohm reader. I had a brain fart when I mentioned .21 per coil. We control vented a vcm stack in 2017 with two per say unmarried batteries if you will with a .09 (very very very unsafe series build) it took 58 seconds to vent and the batteries stopped venting after 32 seconds...no thermal runaway. In the end we take chances with these devices everyday, but as long as your not hard shorting something, I believe everything else is slightly fear mongering bs imo

 

[Don29palms]

Excuse me for being a donkey void but if you already know the answer then why ask the question?

 

[Punk In Drublic]

It is a .42 build on a ohm reader. I had a brain fart when I mentioned .21 per coil. We control vented a vcm stack in 2017 with two per say unmarried batteries if you will with a .09 (very very very unsafe series build) it took 58 seconds to vent and the batteries stopped venting after 32 seconds...no thermal runaway. In the end we take chances with these devices everyday, but as long as your not hard shorting something, I believe everything else is slightly fear mongering bs imo

If it is fear mongering then why are you asking the question?

I have no idea what a vent vcm stack is. But if you believe every battery vents, or enters a thermal runaway in the same fashion then anything I have to say is also fear mongering.

And BTW…I never brought up venting, you did. I stated marrying batteries mitigates risk. Mitigating risk is not fear mongering – it’s being responsible!

 

[Classic vaper]

Excuse me for being a donkey void but if you already know the answer then why ask the question?

Simple. I just wanted to see everybodys opinion on the topic. I guess I should have stated that a little better.

 

[Classic vaper]

If it is fear mongering then why are you asking the question?

I have no idea what a vent vcm stack is. But if you believe every battery vents, or enters a thermal runaway in the same fashion then anything I have to say is also fear mongering.

And BTW…I never brought up venting, you did. I stated marrying batteries mitigates risk. Mitigating risk is not fear mongering – it’s being responsible!

Well my view stands still. I have used mods since 2013 in both safe and dangerous ways and have been using series mods since 2015. I just wanted to see other peoples view on the topic. I for sure wasent seeking advice because im as comfortable as a memory foam couch when it comes to the way I vape. I may occasionally sound passive agressive, but it is human nature for most to get uncomfortable from opinions. I just like hearing other peoples views on topics.

 

[Zaryk]

Simple. I just wanted to see everybodys opinion on the topic. I guess I should have stated that a little better.

Should wrap it all up right here. Always check mooch's blog and videos for battery related questions. It's likely he has already covered most questions that one would have.

 

[gpjoe]

Well, seems to me that the bottom line is, a) you are pulling 20 amps at a full charge (0.42-ohms @ 8.4v) which should be ok with appropriately rated batteries and, b) you should ALWAYS use married pairs.

The problem with pairing random batteries comes into play when an older battery cannot keep pace with a stronger, newer battery. The stronger battery will force the weaker battery to try and keep the same current pace even though it may not otherwise be capable, which can result in catostrophic battery failure. It would be like a twenty-year old athlete trying to run a 10k race while handcuffed to a ninety-year old person. The older person would likely fail.

 

[Punk In Drublic]

Well my view stands still. I have used mods since 2013 in both safe and dangerous ways and have been using series mods since 2015. I just wanted to see other peoples view on the topic. I for sure wasent seeking advice because im as comfortable as a memory foam couch when it comes to the way I vape. I may occasionally sound passive agressive, but it is human nature for most to get uncomfortable from opinions. I just like hearing other peoples views on topics.

So all of us, including experts in the field and your local vape shop feel marrying batteries is important – you feel it is fear mongering because you are comfortable with your vape?

 

[Classic vaper]

So all of us, including experts in the field and your local vape shop feel marrying batteries is important – you feel it is fear mongering because you are comfortable with your vape?

Correct! While I agree that using unmarried batteries is more risky, they could vent...not explode. According to Mooch, a lithium ion battery explosion is caused by thermal runaway via a hard short (mentioned since he is worshiped here). Simply using batteries in series wont cause a hard short. That is caused by failure to complete a circut from reversed polarity on torn wraps, non protruding positive pin ect...
Proper venting is key to make venting not as worrysome.

 

[gpjoe]

They can explode.

I have heard of this long before vaping - among flashlight enthusiasts. Seen pictures of exploded flashlights.

It CAN happen, maybe not every time, but personally, I would never risk my own hands and face to unmarried batteries.

 

[Classic vaper]

They can explode.

I have heard of this long before vaping - among flashlight enthusiasts. Seen pictures of exploded flashlights.

It CAN happen, maybe not every time, but personally, I would never risk my own hands and face to unmarried batteries.

That is very true, but we have to remember that almost all flashlights are constant contact. Once you press the button, they will continue to draw power from a battery until clicked off. Mods only fire while pressed unless there is an issue of somekind, therefore reducing battery heat from draw power. In the end it is to each their own. I could get set on fire by a guy doing a drive by with a flamethrower wishing I would have got hurt by a mod failure. Life is not a garunteed safety thing in any field.

 

[Punk In Drublic]

Correct! While I agree that using unmarried batteries is more risky, they could vent...not explode. According to Mooch, a lithium ion battery explosion is caused by thermal runaway via a hard short (mentioned since he is worshiped here). Simply using batteries in series wont cause a hard short. That is caused by failure to complete a circut from reversed polarity on torn wraps, non protruding positive pin ect...
Proper venting is key to make venting not as worrysome.

I never said unmarried batteries would explode or enter a thermal runaway event. Read my post – “It’s not a matter of venting, but reducing risk.”

I elaborated on your comment about venting which is merely releasing excess pressure. Venting is a low pressure release, barely registering an increase of pressure within a sealed device.

Thermal runaway is an uncontrolled decomposition due to a rapid increase of internal temperature. Depending on cell, it can release several liters of gas within milliseconds. A rapid increase of internal temperature does not have to be caused by a hard short. No hard shorts, no torn wraps, no reverse polarity, no non hybrid safe 510’s in a Tesla – but they’ve experienced thermal runaway!