Battery Heat

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Nanooks

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Had an interesting debate recently regarding high drain batteries. There seems to be this fear of high power mods / sub-ohm set-ups that you must have 30/35 amp batteries, and if you don't, your going to have your mod blow up in your face. These fears are the same reason why lithium-ion batteries are only now being brought mainstream where they have been in existence since Regan was president (that was 1980 for you younger generation).

I have a .24 ohm RDA, and have 18650 30 amp, AW IMR 18490, and AW IMR 18350. Well the 30 amp 18650 is the only one I can use right, cause the other 2 have too low of an amp limit to use most people would say. First all batteries have a burst rating which is double (most times) the standard amp rating, so for 5 - 10 second draw you are bursting within the allowed amp rating. Well that covers the 18490 since the amp rating is 14-16 amps, so what about the 18350. Surely if you fire it up its going to "take your face off". These are batteries, not nuclear power cells. Voltage under load for 18650 30A = 3.5 volts. For the AW IMR 18490 = 3.6 volts (AW's are still the best made). 18350 voltage under load at .24 ohms = 2.7 volts. It didn't blow up, it didn't melt, it didn't even get warm. It just didn't give the voltage under load that the correct amp limit batteries gave.

Ok, whoop de do, why should I care. Cause heat is the issue. Think of your battery as an engine. If your driving your car down the highway at 65 mph, there is no issue. Now if you are towing a semi behind you, your not going to go 65 mph, and you are going to add so much heat to your engine that it will blow up.

Your carto tank / clearomizer setups will work with most 18xxx battery out there. That's your family car, and if you don't abuse it you should never have a problem. Once you go into the genesis / RDA / RBA setup you put a large strain on the batteries (under 1 ohm). Just because you have a 30 amp battery doesn't mean you have nothing to worry about. My 30 amp batteries still gets warm. Heat is the killer of batteries. You can do all this research, buy fancy meters, and pull out your calculus notes to do the math. All it takes is a simple touch of the hand.

If its hot, let it cool, or swap batteries.
 

Baditude

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I have a .24 ohm RDA,
So, which metering device are you using? Unless its a Fluke or similar high-precision meter, you've got a lot of faith that your meter is accurate within 0.2 ohms. O.2 ohms is 0.2 ohms away from a dead short, which will send ANY battery, regardless of how many amps it has, into thermal runaway. That's just too little margin of safety in my book.

IMR_battery_post-venting.jpg

Battery chemistry has come a long way in just 2 years. There were no 30 amp batteries available back then. However, pushing a battery as hard as sub-ohm vapers do puts a lot of stress on even these batteries OVER TIME. Don't expect these batteries to sustain their great specs if you push them hard day in and day out. Please check you battery voltage after you remove them from your charger and your mod to insure they are still healthy enough to do what you ask them to do.
 

zoiDman

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If its hot, let it cool, or swap batteries.

I'm I the Only Person who thought when I read this that Nobody is going to do that?

What are people going to do, Take 3 or 4 Hits and then Let thier Mod Cool down for 10 Minutes?

And isn't there a Fundamental Rule that if the Battery in Anything gets Hot while Under Load, that you are Putting Too Much Load on the Battery?
 
I'm I the Only Person who thought when I read this that Nobody is going to do that?

What are people going to do, Take 3 or 4 Hits and then Let thier Mod Cool down for 10 Minutes?

And isn't there a Fundamental Rule that if the Battery in Anything gets Hot while Under Load, that you are Putting Too Much Load on the Battery?

There is, but it gets a bit foggy (Hah! See what I did there!) when vaping. Your atomizer is producing heat, which can/does transmit to the metal shell of your device.

In my case, using a pen style, it's actually noticeable. Never burning hot, but quite warm. I'm not overdrawing the battery (2.0 ohms, +/- 0.2), I'm just transmitting heat through the metal as I chain vape.

As you noted, in a mod if the battery's getting hot, you're doing something wrong. Stop immediately and re-evaluate.
 

zoiDman

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As you noted, in a mod if the battery's getting hot, you're doing something wrong. Stop immediately and re-evaluate.

Ya know what Kinda Worries me?

Is that we seem to Live More and More in a World where People Trust Numbers that they Read more and more. And do Not Follow the Common Sense advise that I Quoted above.

People seem to Blindly Trust Amp Ratings that they Read on some Sellers Web Site. Not Everyone. But a Lot of People do.

When I first got into VV, I spent awhile poking around the Flashlight forum reading about Batteries. I was kinda Shocked when I would see someone Test a Battery and the Results would Fall Way Below what the Advertised Specs where,

But what Really Blew My Mind was when Nobody seemed Surprised. It's like I found out that All this Time, Many of these Specs had been Overinflated. Or Derived from Calculation rather than thru Physical Testing.

And that I was the Last person to the Party. So I was the Last to Know.

LOL
 

Baditude

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Had an interesting debate recently regarding high drain batteries. There seems to be this fear of high power mods / sub-ohm set-ups that you must have 30/35 amp batteries, and if you don't, your going to have your mod blow up in your face. These fears are the same reason why lithium-ion batteries are only now being brought mainstream where they have been in existence since Regan was president (that was 1980 for you younger generation).

I have a .24 ohm RDA, and have 18650 30 amp, AW IMR 18490, and AW IMR 18350. Well the 30 amp 18650 is the only one I can use right, cause the other 2 have too low of an amp limit to use most people would say. First all batteries have a burst rating which is double (most times) the standard amp rating, so for 5 - 10 second draw you are bursting within the allowed amp rating. Well that covers the 18490 since the amp rating is 14-16 amps, so what about the 18350. Surely if you fire it up its going to "take your face off". These are batteries, not nuclear power cells. Voltage under load for 18650 30A = 3.5 volts. For the AW IMR 18490 = 3.6 volts (AW's are still the best made). 18350 voltage under load at .24 ohms = 2.7 volts. It didn't blow up, it didn't melt, it didn't even get warm. It just didn't give the voltage under load that the correct amp limit batteries gave.
I'm not sure why you are fixated on the voltage under load and not the "current" (amps drawn from the battery by the coil). This is what becomes dangerous with sub-ohm coils. Pull more current (amps) from the battery than it can handle and it will most likely vent, and possibly explode, like the AW 18490 IMR battery below.

IMR_battery_post-venting.jpg

Amps in continuous discharge rate happens to be the current standard specification used for sub-ohms, not amps pulse rate.

18650 30 amp battery with 0.24 ohm coil = 17 amp draw :thumb:

18650 10 amp battery with 0.24 ohm coil = 17 amp draw :danger:

18490 16 amp battery with 0.24 ohm coil = 17 amp draw :danger:

18350 6 amp battery with 0.24 ohm coil = 17 amp draw :danger:

Ohm's Law Calculator

If a battery becomes warm to touch, it is being over-worked. Don't fool yourself. A warm battery means it could be having internal changes to its chemical and physical structure making it unsafe to use.

As mentioned above, some manufacturers and vendors overstate their battery specifications to make their batteries appear competitive with the top battery manufacturers. One in particular has a notorious history of doing this. Independent testing has revealed that these batteries fail in living up to their specifications.
 
Last edited:
Ya know what Kinda Worries me?

Is that we seem to Live More and More in a World where People Trust Numbers that they Read more and more. And do Not Follow the Common Sense advise that I Quoted above.

People seem to Blindly Trust Amp Ratings that they Read on some Sellers Web Site. Not Everyone. But a Lot of People do.

When I first got into VV, I spent awhile poking around the Flashlight forum reading about Batteries. I was kinda Shocked when I would see someone Test a Battery and the Results would Fall Way Below what the Advertised Specs where,

Bell curve and all that. I'm sure they set those pretty high--99% confidence? Probably higher, but I doubt it's six sigma or anything like that. And they can't guarantee storage or shipment conditions, nor consumer-level charging conditions, so those can and will drift. Really, that spec is only for the moment it left the factory.

Drop it and that spec just changed.

But what Really Blew My Mind was when Nobody seemed Surprised. It's like I found out that All this Time, Many of these Specs had been Overinflated. Or Derived from Calculation rather than thru Physical Testing.

Yep. In the battery game, I tend to always assume that batteries have overinflated capacity. You might, theoretically, get that with very low draw under perfect conditions. I'm not going to see anything close to that with higher draw and real-world conditions.

The same is true with NiMH. My cheapest (pennies per) are rated at 200 mAh, and good for small solar designs. I also assume and have had it proven out, that they're closer to 100 mAh. My good AC Delco ones are rated at 2,500 and really do deliver that under some punishing conditions, so sometimes they really are good ones.
 

brickfollett

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I'm not sure why you are fixated on the voltage under load and not the "current" (amps drawn from the battery by the coil). This is what becomes dangerous with sub-ohm coils. Pull more current (amps) from the battery than it can handle and it will most likely vent, and possibly explode, like the AW 18490 IMR battery below.

View attachment 337211

Amps in continuous discharge rate happens to be the current standard specification used for sub-ohms, not amps pulse rate.

18650 30 amp battery with 0.24 ohm coil = 17 amp draw :thumb:

18650 10 amp battery with 0.24 ohm coil = 17 amp draw :danger:

18490 16 amp battery with 0.24 ohm coil = 17 amp draw :danger:

18350 6 amp battery with 0.24 ohm coil = 17 amp draw :danger:

Ohm's Law Calculator

If a battery becomes warm to touch, it is being over-worked. Don't fool yourself. A warm battery means it could be having internal changes to its chemical and physical structure making it unsafe to use.

As mentioned above, some manufacturers and vendors overstate their battery specifications to make their batteries appear competitive with the top battery manufacturers. One in particular has a notorious history of doing this. Independent testing has revealed that these batteries fail in living up to their specifications.

Was that Efest?
 

Nanooks

Senior Member
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Feb 1, 2013
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179
Salt Lake
Thank you for proving my point that there is too much fear of the battery. Just so I can be clear in my intent with this post: Don't fear the battery, fear the heat.
As to all the other posts, if you want to stick with your cute little fairy wand 5 watt things cause you feel safer, then by all means. I have gone back to smoking because it doesn't work for me. So in order to get something that keeps me off cigarettes, I need something with more than 30 Watts of power. I am perfectly comfortable having a battery next to my face, with the power I am consuming. I would be ok if the risk was ten fold. Cause compared to the alternative, its still safer, and healthier.
 

KenD

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With a fully charged battery, when the inline volt meter is showing 3.5 (or whatever) you're still drawing 4.2 volts from the battery, some of it is just lost due to the resistance of the mod and battery. That means that you need to calculate your amp draw on the basis of 4.2v, as 3.5 (or whatever) under load doesn't give you a proper indication of how hard you're pushing the battery. Am I correct?

Sent from my GT-I9100 using Tapatalk
 
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