Comparing battery life - practical experience

[Silver]

Been using this a lot this week with the Zeus sub-ohm tank it came with and various RTA's. Apart from better performance at higher wattage and increased battery life due to accommodating a 21700 battery, nothing learnt could easily of just winged the review coming up very soon but that would of been wrong. It's just a slightly larger Aegis Solo, a cracking single battery option, Chicken dinner!!!!!

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Tell me @Timwis , how much extra juice would you say you get through using a 21700 battery versus 18650 battery? In practice?

Reason I ask is that I am wondering whether to get a 21700 device (single batt). To increase battery capacity and have less battery changes. But if its only like 20% more life, then its probably not all that beneficial and I will stick with my 18650 single batt mods.

 

[Jengz]

Tell me @Timwis , how much extra juice would you say you get through using a 21700 battery versus 18650 battery? In practice?

Reason I ask is that I am wondering whether to get a 21700 device (single batt). To increase battery capacity and have less battery changes. But if its only like 20% more life, then its probably not all that beneficial and I will stick with my 18650 single batt mods.

Can i give my input? I've noticed battery life also depends on the mod. My truest results are from my mech mods. If i compare the use of a 21700 samsung 40T and a 18650 Samsung 30Q on my mech devices, running them in MTL mode, i get close to a day more with my 21700 setup which in theory shouldnt be the case.

The 21700 is 4000mah battery and the 18650 a 3000mah battery so in theory it should be about 33% increase in battery life if you do the math. I however feel it is a bit more. I dont know physics all that well but maybe its because the amp rate on the 21700 is a lot higher so i dont feel the drop in power as fast as i do with the 18650.

In my experience, if I owned a 21700 noisy cricket, i do not think i would be using 18650s any more. I would be happy to only run 21700s as i much orefer them, especially with the my mechs.

Sorry for hijacking your question @Timwis @Silver

 

[Silo]

I can relate. 40T is more powerful and more mah, so when using it at 50W compared to a 30Q, it lasts quite a bit longer. Also I feel that the 30T isn't much stronger then the 40T, if any.

 

[Timwis]

Can i give my input? I've noticed battery life also depends on the mod. My truest results are from my mech mods. If i compare the use of a 21700 samsung 40T and a 18650 Samsung 30Q on my mech devices, running them in MTL mode, i get close to a day more with my 21700 setup which in theory shouldnt be the case.

The 21700 is 4000mah battery and the 18650 a 3000mah battery so in theory it should be about 33% increase in battery life if you do the math. I however feel it is a bit more. I dont know physics all that well but maybe its because the amp rate on the 21700 is a lot higher so i dont feel the drop in power as fast as i do with the 18650.

In my experience, if I owned a 21700 noisy cricket, i do not think i would be using 18650s any more. I would be happy to only run 21700s as i much orefer them, especially with the my mechs.

Sorry for hijacking your question @Timwis @Silver

Yeah, although i review products i'm really not all that technically minded so only go by what my experience is using so many different products. I agree that using a 21700 in a mech and comparing to 18650 shows not only how much increased life you can get but the definite improvement in performance. @Silver battery life in general like @Jengz say's depends not just on the battery but how you vape and efficiency of the device it'self but the extra life is very noticeable so yes 33% over a 30Q but it just seems more. The biggest advantage is when using devices nearer their wattage limits then it's not just about the extra battery life but also the better performance really comes into play, by choice i don't vape at the wattage with devices that is expecting a lot of wattage per battery but like with a car it's nice to have it under the hood!

 

[Christos]

Tell me @Timwis , how much extra juice would you say you get through using a 21700 battery versus 18650 battery? In practice?

Reason I ask is that I am wondering whether to get a 21700 device (single batt). To increase battery capacity and have less battery changes. But if its only like 20% more life, then its probably not all that beneficial and I will stick with my 18650 single batt mods.

Another opinion if I may.

I find I can do 11 ml on a 21700 vs 6 to 7ml on a 18650.

I am however using the 40T’s on a mosfet chip/ semi mech.

 

[Timwis]

Another opinion if I may.

I find I can do 11 ml on a 21700 vs 6 to 7ml on a 18650.

I am however using the 40T’s on a mosfet chip/ semi mech.

I thought @Silver by juice meant battery juice. Seems a weird question unless it's just me asking how a battery effects e-liquid consumption normally that would be asked in regard what wattage you vape at or other variants fail to see what different battery types has to do with juice efficiency.

 

[Timwis]

I thought @Silver by juice meant battery juice. Seems a weird question unless it's just me asking how a battery effects e-liquid consumption normally that would be asked in regard what wattage you vape at or other variants fail to see what different battery types has to do with juice efficiency.

Or to put it another way the usual thing people would be interested in when choosing between batteries would be battery life and performance not a question of e-liquid consumption.

 

[Moey_Ismail]

Or to put it another way the usual thing people would be interested in when choosing between batteries would be battery life and performance not a question of e-liquid consumption.

I think what @Silver was asking is how many mls of juice he would be able to get through on a 21700 before having to change the battery vs a 18650.

 

[Timwis]

I think what @Silver was asking is how many mls of juice he would be able to get through on a 21700 before having to change the battery vs a 18650.

Yeah but i don't understand what that matters and it would be completely different for everyone because so many variants. I might just be being a bit dumb and could be a perfectly normal question but to me i'm scratching my head at it. Surely it's battery life that matters and e-liquid consumption will just be comparable.

 

[Silo]

Yeah but i don't understand what that matters and it would be completely different for everyone because so many variants. I might just be being a bit dumb and could be a perfectly normal question but to me i'm scratching my head at it. Surely it's battery life that matters and e-liquid consumption will just be comparable.

Haha, it seems quite common to compare how many mls a battery can give.

 

[Timwis]

Haha, it seems quite common to compare how many mls a battery can give.

I always thought it was mAh's lol. In all sincerity i'm not trying to be difficult i just don't really understand the point of the question!

 

[Silo]

It is like you said. The power does come into play as well. So I guess a lot of people have opted for how many mls they can get out of a battery.

 

[Silver]

Am making this thread to house several posts in the "Whats in your hand thread"

I think its useful to know how various batteries stack up in terms of practical battery life

One can read the mah specs etc of the batteries - but practical day to day experiences are more useful imo.

One of the ways I measure battery life of a battery is how many mls of juice I get through on it (with the same setup - mod, coil and power) before the battery needs to be changed.

In a regulated mod, its easy, you replace the battery when the mod tells you its flat

In a mech, it's when the battery feels too weak to give you your desired vape.

As an example, on my Reo Mech I get about 5ml of juice out of a LG HG2 using my preferred MTL coil (0.5 ohm paracoil - so about 30W total). It so happens to be a convenient amount because that's about the size of the bottle - so when I refill I change the battery.

If you give me an old battery or something with less life - I will be able to tell you after using it in the setup I know well. If I only get 3/4 of a bottle - then either its an old battery or something with less battery life.

Which brings me to another very important point about practical battery life. That is usable mah

• We all know that battery manufacturers specify the mah of their batteries. I.e. milli amp hours. However, there is a "usable mah" range, which is much less than the quoted total mah.
• What this means (on a mech for example) is that you get to a point where the voltage is too low to give you the desired vape.
• So even if the mah of a battery is 4,000 mah and another one is also 4,000, the internals may be such that the one gives you more usable mah than the other.
• Alot has to do with the internal chemistry of the battery and I am not perfectly familiar with it all - but I think the lower the internal resistance the better as well.
• If you look at the spec charts of a battery (i.e. when its drained) you will see what I am talking about. When the voltage drops as the battery is drained you get to a point where it won't give you a good vape anymore - long before its totally drained. Total drainage is the total mah of the battery - but that point where you can't vape happily anymore is much sooner and that is "usable mah"
• Not all batteries have the same usable mah and my feeling is that the usable mah, although correlated with the total mah, is not always correlated.

So checking how much juice you get through seems like the most reliable practical measurement for us. (obviously keeping the same mod and setup - ie coil resistance and power)

Will move those other posts here and when done they will appear above this one.

 

[Silver]

Thanks @Jengz , @Silo and @Christos for your inputs

@Timwis - maybe I didnt explain myself properly when I asked you that question - I should have said how many mls of juice can you get through on the 21700 batt vs the 18650 batt all else equal. @Moey_Ismail explained it better than me. Thanks Mo!

If you read the post above this one - you will see why I ask that.

As for why that is important - it may not be that important to many you are right - but to me it is quite important and interesting. I like to get the most life out of my batteries for my use. And if there are two batteries on offer and the one has more life than the other (at my power setting) then that's the one I would like to buy.

 

[Silver]

Another opinion if I may.

I find I can do 11 ml on a 21700 vs 6 to 7ml on a 18650.

I am however using the 40T’s on a mosfet chip/ semi mech.

Thanks @Christos !

Just checking - are the 18650's you getting 6-7ml on a normal mech? Or the same device as the 21700?

 

[Silver]

Can i give my input? I've noticed battery life also depends on the mod. My truest results are from my mech mods. If i compare the use of a 21700 samsung 40T and a 18650 Samsung 30Q on my mech devices, running them in MTL mode, i get close to a day more with my 21700 setup which in theory shouldnt be the case.

The 21700 is 4000mah battery and the 18650 a 3000mah battery so in theory it should be about 33% increase in battery life if you do the math. I however feel it is a bit more. I dont know physics all that well but maybe its because the amp rate on the 21700 is a lot higher so i dont feel the drop in power as fast as i do with the 18650.

In my experience, if I owned a 21700 noisy cricket, i do not think i would be using 18650s any more. I would be happy to only run 21700s as i much orefer them, especially with the my mechs.

Sorry for hijacking your question @Timwis @Silver

Thanks very much @Jengz - and no you were not hijacking - this is the type of thing I was wondering.
So thanks for your input.

 

[Silver]

I can relate. 40T is more powerful and more mah, so when using it at 50W compared to a 30Q, it lasts quite a bit longer. Also I feel that the 30T isn't much stronger then the 40T, if any.

Thanks for the input @Silo , appreciate it

 

[Silver]

The reason I am interested in this is that the 21700 single batt mods are not much bigger than the 18650 batt mods. At least not what I can see. So the extra size may be a worthy price to pay to get much longer battery life.

By battery life I mean how many mls of juice I can get through before needing to do a battery change.
(The mls of juice I vape per day is pretty constant)

 

[Jengz]

The reason I am interested in this is that the 21700 single batt mods are not much bigger than the 18650 batt mods. At least not what I can see. So the extra size may be a worthy price to pay to get much longer battery life.

By battery life I mean how many mls of juice I can get through before needing to do a battery change.
(The mls of juice I vape per day is pretty constant)

In mtl mode on a tube mech using an 18650 amd my savour rta i get through about 4-5 tank refills, so 8-10mls.

Same setup in 21700 mode about 7-8 tank refills so 14-16 mls on average.

Bare in mind, i use a 0.6 to 0.7 ohm build in my mtl tanks. I also do not take looooong drags in mtl mode unless im vaping a 6mg-9mg juice because I dont have enough hair on my chest for that lol.

 

[NecroticAngel]

My experience just with single mods. I have a tesla punk 86w tube and a rincoe me hman 80w tube. Tesla has 2 violence coils in which is a bit much for a tube mod. Runs fine though but because after half a battery they power down a little so you can vape longer I tend to change the battery at half. Have to use 5 or 6 half batteries a day. (at 47w)
Rincoe Mechman is better for me because it doesn't have that battery saver. It just gives full power all the time. I use 3 batteries a day. That being said I got a stupid mesh setup and that takes nearly no battery at all. If the thing had any flavor I'd still only need 1 battery a day as mesh uses so little. So I spose the answer is depends on your coils and wattage. The violence coils take alot of heating up so I thing at least a third of my batteries go on just doing that

 

[Raindance]

In terms of cells being used for vaping, there are two loads on the cell. The first is the one we are all very conscious of which is the coil we are running. The other which is seldom considered, is the "coil" that heats up the cell while we vape. Aka the cell's internal resistance.

Although all the cells we use are considered to be high draw cells, there is a noticeable trend in capacity versus amp rating. You will note large capacity cells usually have a lower amp draw rating and low mAh cells give higher draw ratings. This is due to the chemical composition of the cells. The more the chemistry favours large mAh capacity, the more it tends to heat up when Amp draw increases as there is less low resistance "conductor" chemicals in the mix because they were replaced with "current creating" chemicals. The resulting higher internal resistance inside the cell causes it to heat up more than a high draw cell at the same load.

Having used both 30Q's and VTC5S' cells in my standard setup mech squonker, the VTC5 actually gives me an ability of about 10% more juice consumption than the 30Q. Although the 30Q is a 3000mAh cell, it loses a considerable amount of mAh's due to heating from internal resistance at high draw levels. So much so, that the 2500 mAh VTC5 ends up availing more mAh's to heating the resistor that matters.

As with all things electrical (well mostly), resistance increases with temperature. If you were comparing these two cells both driving a 10W load, the 30Q would beat the pants off the VTC as heat buildup would be minimal.

Regards

 

[Puff the Magic Dragon]

By Mooch.

Inside each battery there are two things that can interfere with the flow of current in or out of the battery. The two of them together are called the internal resistance of the battery.

Why is internal resistance important? It’s what causes your battery to heat up and the voltage of your battery to sag.

So what are the two things that add together to create the the battery’s internal resistance?

First, it’s the actual resistance of the metal contacts and the internal structure that carries current through the battery (the electrolyte, separator, etc.). This resistance is typically only a few milliohms (thousandths of an Ohm) to a couple dozen milliohms.

Second, it’s the efficiency of the chemical reactions and flow of the ions through the battery. These ions can’t be transported through the battery at any rate we want. As the current level rises there is a difference in the density of the ions in different parts of the battery. This change in the density and distribution of the ions results in a voltage difference between different points of the battery. We see this effect as a voltage change as soon as current flows. Knowing the voltage change and how much current is flowing we can use Ohm’s Law to determine the equivalent resistance that would cause the same voltage change.

These two resistances added together (one actual and one equivalent) give you the internal resistance of the battery…or the IR. The “DC IR”, direct current internal resistance value, is the one we want to use. Since we pulse our batteries for up to several seconds we want to use the IR value measured when switching between two steady current values, one of them being zero amps in our case because we pulse our batteries on/off.

The “AC IR” value often quoted in battery datasheets is lower but this is something we would use only when measuring performance in an unregulated PWM device. It’s measured by pulsing the current at 100Hz or 1000Hz.

The typical DC IR (which I’ll just call IR) of a new Samsung 25R battery at room temperature is roughly 0.022-0.025 ohms. For a high-capacity 5200mAh 26650 battery the IR can be as high as 0.06 ohms. This is what causes the large voltage sag when we try to vape with these high-capacity 26650’s at higher power levels.

The IR of a battery affects how we vape by causing the voltage to sag during discharging and the voltage to rise during charging. Since these voltage drops or rises are just temporary, and aren’t the true voltage of the battery, this can be a problem.

 

[Christos]

Thanks @Christos !

Just checking - are the 18650's you getting 6-7ml on a normal mech? Or the same device as the 21700?

Yes, the device is the same and the atty the same.

I rewick after every bottle and the fact that I only need 1 battery per bottle is the reason I have moved over to 21700s .
I actually use 21700s more than 18650s and the main reason is the reliability of one battery per 1 bottle of juice for me.

 

[Christos]

A size comparison.

 

[Stranger]

@Silver

I get where you are coming from. On an evening I will put down my ADV and just vape what I call a session juice

Kit : EHpro armour semi mech

Vapefly RDTA, currently a .26 fused clapton

DTL, restricted draw

18650 with adapter ............. 5-6 refills of the 2 ml tank

20700 ............ 8-9 refills same tank.

Same setup on a straight mech and the 20700 fires quicker and ramps up sooner than the 18650