How hard do you push your Samsung batteries?

[XRaptureX]

I want to start out by thanking those who posted in my "Recommendations for a mechanical mod" thread for all the excellent suggestions. Now that I've made my decision, and I've got something on the way, I have a couple questions about batteries.

The Samsung 25R is rated at 20 amps. This would mean that .2 ohms @ 80 watts would be my limit. Knowing me, I would probably build a little above that just to give myself a buffer of safety, but I've heard of people who have built much lower than that without issue. So my first question, and we're going to focus on a single battery mechanical mod, is just how low do you usually build on a single Samsung 25R?

My second question is concerning regulated mods, or even unregulated mods, that run two 18650 batteries in parallel. Does running two batteries in this way increase what they can handle? If so, by how much?

These forums have been just fantastic, and I want to thank the community again for all the help.

End of Line.

 

[Baditude]

I only build down to 0.6 ohm for my mechanical mod. 0.2 ohm will draw 21 amps current, so that's over the 20 amp continuous discharge rate of a Samsung25R.

Coil amp draw from Ohm's Law calculations for Mechanical Mods:

1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
0.0 ohms = dead short = battery goes into thermal runaway​

Everyone is free to set their own parameters, and I can only say what mine are. I try to never exceed 50% of the CDR (continuous discharge rating) of a fully charged battery (4.2v). So with a 20 amp battery, that 50% would be 10 amps continuous -- a 10.5 amp draw from a 0.4 ohm coil).

The reason that I place a 50% limit is because as a battery ages the mAh of the battery degrades, as the mAh degrades so does the batteries C rating (amp limit). So down the road, your 20A battery may only be a 10A battery.

You may be placing a lot of faith in a cheap ohm reader in making a precise and accurate reading to a tenth or hundredth of an ohm. The most accurate and recently calibrated digital multimeters can cost over $1000. Most of us are using cheap $20 meters with unknown accuracy and precision. My Provari's meter and my box Ohm meter differ by 0.2 ohms consistently. Which one is most accurate? I don't really know, so I use the more conservative measurement.

A loose post screw holding your coil on your RBA can drastically lower your coil resistance by as much as 0.5 ohms (from personal experience).

At the time of this writing (July 2015), there are no mod batteries that can deliver more than 30 amp CDR. Any advertisement of over 30 amps is either marketing hype or a pulse discharge rating (a spec we choose not to use).

The batteries we have available can be quite safe if you use the right batteries for the right application and do not abuse them beyond their recommended amp limit. Most bad battery incidents result from user error, wrong calculations, ignoring safe battery practices, or using a mod without adequate vent holes for a battery which goes into thermal runaway.

A battery venting in thermal runaway will release extremely hot gas, toxic chemicals, and rarely flames. Once this chemical reaction begins, there is no stopping it. The gas can build up inside a mod, and if there is inadequate venting the mod becomes a little pipe bomb.

Battery Basics for Mods

I personally use Samsung25R and Sony VTC4 batteries in my mechanical using 0.6 ohms.

 

[XRaptureX]

I only build down to 0.6 ohm for my mechanical mod. 0.2 ohm will draw 21 amps current, so that's over the 20 amp continuous discharge rate of a Samsung25R.

Coil amp draw from Ohm's Law calculations for Mechanical Mods:

1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
0.0 ohms = dead short = battery goes into thermal runaway​

Everyone is free to set their own parameters, and I can only say what mine are. I try to never exceed 50% of the CDR (continuous discharge rating) of a fully charged battery (4.2v). So with a 20 amp battery, that 50% would be 10 amps continuous -- a 10.5 amp draw from a 0.4 ohm coil).

The reason that I place a 50% limit is because as a battery ages the mAh of the battery degrades, as the mAh degrades so does the batteries C rating (amp limit). So down the road, your 20A battery may only be a 10A battery.

You may be placing a lot of faith in a cheap ohm reader in making a precise and accurate reading to a tenth or hundredth of an ohm. The most accurate and recently calibrated digital multimeters can cost over $1000. Most of us are using cheap $20 meters with unknown accuracy and precision. My Provari's meter and my box Ohm meter differ by 0.2 ohms consistently. Which one is most accurate? I don't really know, so I use the more conservative measurement.

A loose post screw holding your coil on your RBA can drastically lower your coil resistance by as much as 0.5 ohms (from personal experience).

At the time of this writing (July 2015), there are no mod batteries that can deliver more than 30 amp CDR. Any advertisement of over 30 amps is either marketing hype or a pulse discharge rating (a spec we choose not to use).

The batteries we have available can be quite safe if you use the right batteries for the right application and do not abuse them beyond their recommended amp limit. Most bad battery incidents result from user error, wrong calculations, ignoring safe battery practices, or using a mod without adequate vent holes for a battery which goes into thermal runaway.

A battery venting in thermal runaway will release extremely hot gas, toxic chemicals, and rarely flames. Once this chemical reaction begins, there is no stopping it. The gas can build up inside a mod, and if there is inadequate venting the mod becomes a little pipe bomb.

Battery Basics for Mods

I personally use Samsung25R and Sony VTC4 batteries in my mechanical using 0.6 ohms.

Wow. That was more informative than I could have hoped for. Fantastic. It is a Greek tragedy that I can not like your post more than once.

End of Line.

 

[Eekins]

I don't like tube mechs, so I've never used anything with only one 25R battery, however I have 6 and I use them in either my sigelei or a dual 18650 mech mod. I've pushed a pair of 25R's to 0.15 ohms. 28amps total. I like giving myself a minimum of 10amps of space.

 

[DaveSignal]

I usually use dual battery mechs and almost always build below .2, sometimes slightly below .1 even. With a single battery I will sometimes keep it around .21 (20 amps), unless I feel like doing lower, in which case I might put a .15 on there without thinking twice... the battery won't last very long though before you need to recharge it.

So, basically, I use CDR as a general guideline, but sometimes I will pull more amps than the CDR. I am very careful with my mods, though. I would never let them self-fire. I do regular maintenance and cleaning/polishing. I make sure the mods have proper venting. And I know exactly what to expect from my builds. If something is not right, I fix it. I have around 40 mech mods and have never vented a battery due to a low build.

So, I guess the short answer is, you can do it. And you aren't going to damage anything if you are careful. But the batteries aren't rated to put out like that continuously, so if your switch somehow gets stuck and the mod self-fires, the battery is going to get too hot and could possibly vent, which could wreck your mod, especially if there are any delrin parts on it.

 

[XRaptureX]

I don't like tube mechs, so I've never used anything with only one 25R battery, however I have 6 and I use them in either my sigelei or a dual 18650 mech mod. I've pushed a pair of 25R's to 0.15 ohms. 28amps total. I like giving myself a minimum of 10amps of space.

Ok, wait... are you saying that if you have two Samsung batteries you're actually increasing the maximum amps to 40 instead of 20? Your using these parallel?

End of line.

 

[XRaptureX]

I usually use dual battery mechs and almost always build below .2, sometimes slightly below .1 even. With a single battery I will sometimes keep it around .21 (20 amps), unless I feel like doing lower, in which case I might put a .15 on there without thinking twice... the battery won't last very long though before you need to recharge it.

So, basically, I use CDR as a general guideline, but sometimes I will pull more amps than the CDR. I am very careful with my mods, though. I would never let them self-fire. I do regular maintenance and cleaning/polishing. I make sure the mods have proper venting. And I know exactly what to expect from my builds. If something is not right, I fix it. I have around 40 mech mods and have never vented a battery due to a low build.

So, I guess the short answer is, you can do it. And you aren't going to damage anything if you are careful. But the batteries aren't rated to put out like that continuously, so if your switch somehow gets stuck and the mod self-fires, the battery is going to get too hot and could possibly vent, which could wreck your mod, especially if there are any delrin parts on it.

I want to make sure I understand this. Your saying that the 20 amp limit is only for continuous draw? You're saying that in short pulses you can actually go beyond that?

.2 ohms is probably as low as I would go, but I just didn't like the idea of taking a battery to its limit. According to what I'm hearing from you, I wouldn't be doing that. As long as I'm only firing it for a couple of seconds of course.

End of line.

 

[Froth]

I have been using the Samsung 25R at 0.12 ohms for over a year mostly in single battery mechanical tube mods, in that year I have had zero incidents to report of any kind and keep in mind that I generally charge 3-4 batteries a day, so that's hundreds of cycles over a years time without a single incident. After about ~150 charge cycles at that sort of resistance I notice the batteries are pretty down on capacity(say, 60%) compared to a brand new cell so to be safe because of my limit pushing usage I recycle all of my 25R's at 150 cycles no matter the condition of them.

 

[DaveSignal]

I want to make sure I understand this. Your saying that the 20 amp limit is only for continuous draw? You're saying that in short pulses you can actually go beyond that?

I am saying that yes, CDR is 'continuous discharge rating', meaning it is pulling those amps continuously for the whole charge cycle of the battery, with no breaks.

So, yes, if you have a way to keep that battery cooler, maybe by not doing it continuously, the battery can function just fine with more amps. Many vapers use the CDR as a build limit because it is always safe, even if the mod self-fires and is unattended.

I would put a .2 on a single battery mech. Just be careful about it. Measure your resistances. 2 24g kanthal coils, 6 wraps each, is about .21 ohm. This is a great vape. Its at the CDR limit, so you gotta take care of your mod and watch where you put it down and don't let it self fire. The batteries will work lower too, if you wanted to use something like 22g, but you need to be careful about what you are doing.

 

[XRaptureX]

This is all great information, and I appreciate that it's coming from experience.

I really think I've found my sweet spot and I was just a little nervous to put it on a mechanical mod. 26 guage, 6 wraps, dual parallel coil, .22 ohms. I only posted the picture of it because it came out so darn pretty. Thanks again to everyone for the help.

End of line.

 

[sonicbomb]

Looks handsome, the wicking especially so from what I can see anyway

 

[Thrasher]

I have tortured batteries to never firing again.

Even had em dead short till u could start a fire off my mech button.


I dont mean too, but hey its in a construction environment things happen.

So far the Samsung and the lg he have held up well. Melted a kayfun 4 when my mod hit the bushes once from like 30 feet. That battery runs like new still 3 months later, over a year old.


The batteries we have now are light years ahead of what we started with.

NO battery is 100% safe, but they are def getting better, and a lot of those advances are related to battery tech for power tool packs and electric vehicles as most if not all use 18650 cells.

 

[Eekins]

Ok, wait... are you saying that if you have two Samsung batteries you're actually increasing the maximum amps to 40 instead of 20? Your using these parallel?

End of line.

Sort of. In the mod itself is a 40amp limit with a parallel box mod. The atty pulls 28amps but only 14 from each battery. It splits the load up.

 

[WattWick]

I try to push mine as little as possible. Only takes the smallest nudge before they tip over and roll onto the floor.

 

[tj99959]

Bad started off by quoting me, so I will only say that a 20a battery doesn't stay a 20a battery forever. So be careful with that.
Do what you want, and I'll still just follow my 50% of CDR rule.

You can do a .4 ohm build that will do everything that a .2 ohm build can do. (and vape twice as long on a charge as well)

 

[MattyTny]

Placing a amperage draw limit on yourself is a good idea if you are getting into mechanical devices. A lot of people will run single 18650s close to the maximum amperage draw for a particular battery. This should only be done if you are well aware of the risks and take care of your batteries as far as knowing when to change them out.

If you are a bit concerned you can look into multiple battery devices. Parallel batteries has an additive effect on the total amperage. Well, more like multiplicative at twice the amperage. There are a bunch of different unregulated ones.

I feel that anything much lower than 0.5ohms can tax a single 18650 quickly. I usually replace after voltage drops below 4.0v as read by a DMM. After sometime you get a feel for it. That's just my personal experience though. Be safe!

 

[philoshop]

Power tools use battery regulation technology, as do electric automobiles. Bypass the battery limits and you will someday be surprised with the result.
Then again it's your face and hands, not mine.

 

[XRaptureX]

Power tools use battery regulation technology, as do electric automobiles. Bypass the battery limits and you will someday be surprised with the result.
Then again it's your face and hands, not mine.

Well that's the whole point of this. To get some good information from experienced people so that I don't blow up my face and hands. Pushing those limits and being uneducated about what you're doing is what will most likely make you a statistic.

End of line.

 

[Thrasher]

S... happens. You abuse any battery and it can fail, rc, cell phones, laptops... billions of these devices used few fail.


The belief that overdriving a cell will assuredly end in destruction is a fallacy plenty of vids showing failure time and time again trying to get cells to pop with the occational success.., plenty of posts on here too about people dead shorting a cell to death.
not denying it kills cells though.

Lets say I have a build that takes 30 or so amps, my battery says 20.


You cannot magically pull more amperage then the cell can actually create. Even in a dead short, it can only develope what its design dictates. 99.995% of the time this results in a burned out cell ( also by design.

Batteries sag so bad after 25amps you need a serious regulated mod to pull what they need out of those dying cells anyways.

As for powertools almost all use 20+ amp cells, samsung in my Milwaukees. Regulation or not 18v @ 25 amps is nothing to scoff at. Battery packs fail as part of life, but almost never is there a catastrophic failure.

 

[JMarca]

Battery packs fail as part of life, but almost never is there a catastrophic failure.

Airplanes almost never crash, until they do... then it's in the news for weeks. Batteries vent and explode more often than you think, typically no one is hurt or the story simply isn't of enough interest to make news.

This industry is very much the exception, if an e-cig blows up every network picks up the story.