26650 Batteries For Sub-ohm In Mech Mod - Current Drain Questions

[1am7h30n3]

Sorry for the late reply on this, updating my notification settings right away!

My current coil on my Tobh is sitting at 0.32Ohm

Right now the most topped up EFest 26650 Red I have is reading in at 4.13V installed in my Hades (not under load)

Under load on the mentioned coil in my Hades, voltage drops to 2.8V

So, yes - it's bad...I don't know why I never bothered to test this before

@M4dm0nk3y Thanks so much for the measurements! With a 0.32ohm build on a fresh battery (4.2V) you are aiming to see current of I = V/R = 4.2/0.32 = 13.125A.



From the above graph of the red efest 26650 batteries, graph from http://lygte-info.dk/review/batteries2012/Efest IMR26650 3000mAh (Red) 2014 UK.html , and working from somewhere around the 0,5Ah portion of the graph (battery might have lost a bit of capacity, not fully fully charged, etc) you're looking at getting a max of 3.55V out of it. Accounting for the battery having been put through quite a few cycles and we're looking at even worse performance, then of course there are losses from the mech mod itself as well as the tobh atty, etc and we start to see where numbers like 2.8V under load come from!

I also tested with my HCigar Nemesis, with a Sony VTC5 and the same atty and coil

4.16V: No load
3.36V: While firing (under load)

It would be interesting to see other people's results as well - I definitely need to do more research

I would put money on the higher voltage to atty measured here being mostly due to the much higher quality VTC5 battery and not mostly due to the different mod used.

The voltage drop for a Reo (has cold plated contacts) is around 0.2V.

@Andre , although it is repeated over and over by the vaping community, this "voltage drop" figure is actually only meaningful if quoted along with the specific battery used (as well as age/condition and resting voltage) and the ohm load being driven. I don't mean to offend anyone here, I just want to get the right info out there.

There is actually no such thing as a "voltage drop", all that is happening is that we can measure a drop in the voltage, which is caused by a current flowing through a resistance (mod/battery internal resistance/resistance through 510 connector etc), the only meaningful figures would be resistances of each part of the chain (battery, atty, coils, mod) but this is extremely hard to break down.

If it seems hard to accept that there is no meaning to "voltage drop" you can test it easily by taking your Reo, putting an atty with a low resistance (say 0.3 or 0.4ohm) on and measuring voltage while firing, then put an atty with a high resistance (say 1ohm or 2ohm) and measure voltage while firing again. You will see two totally different readings, hence no meaning to "voltage drop" without more information.

 

[Chop007]

Hi @drew
I read with much interest you saying that the Purple Efest 35A 2500mah is actually a re-wrapped LG ICR.
I thought it was an IMR battery.
If it is ICR, then that would be bad? Right?

Not All Efest are re wrapped. The trick to getting the genuine batteries, both Efest and Sony VTC's is to know the batteries original real world purpose and then have a connection within specific industry, to get the batteries. Very tricky, many muppets cannot get the originals.

 

[Andre]

Not All Efest are re wrapped. The trick to getting the genuine batteries, both Efest and Sony VTC's is to know the batteries original real world purpose and then have a connection within specific industry, to get the batteries. Very tricky, many muppets cannot get the originals.

These type of general statements do no-one any favours, with the greatest of respect. We have submitted in more than one thread a public statement by Efest that their purple 2500 mAh batteries in fact have a Continuous Discharge Current of only 20A and not the misleading 35A as stated on the battery.

 

[drew]

Not All Efest are re wrapped. The trick to getting the genuine batteries, both Efest and Sony VTC's is to know the batteries original real world purpose and then have a connection within specific industry, to get the batteries. Very tricky, many muppets cannot get the originals.

I disagree, re-wrapping is what Efest does! They don't actually manufacture any cells, they purely source from various manufacturers, re-wrap and market.

 

[Andre]

I disagree, re-wrapping is what Efest does! They don't actually manufacture any cells, they purely source from various manufacturers, re-wrap and market.

Maybe it is a matter of definition here. Re-wrapping, as I understand it generally in battery terms, means putting a new wrapping over the original wrapping - actually more over-wrapping for me. Efest has done that no doubt - have seen some pictures. But they also buy in bare, unwrapped batteries or take off the wrapping of bought batteries and put their own wrapping on. Have checked one of my purple 3100 and it is bare metal beneath the Efest wrapping. Am sure they have learned their lesson with re-wrapping (over-wrapping) as defined above and will not do it any more. They have also stated that from June 2014, with new battery lines, they will show the Continuous Discharge Current in Amps. But their reputation is down the drain, for sure.

 

[Gazzacpt]

Not All Efest are re wrapped. The trick to getting the genuine batteries, both Efest and Sony VTC's is to know the batteries original real world purpose and then have a connection within specific industry, to get the batteries. Very tricky, many muppets cannot get the originals.

Sorry to do this but really? Did you go and research we even supplied links, slating the other retailers calling them muppets was a bit uncalled for. As far as I can tell no one in SA has been selling "fake" Efests. Everyone here has been trying to tell you that efest are rewrapping cells from other manufacturers , much in the way that AW does. AW does not manufacture he sources cells tests the batch to make sure it is capable of the current drain and then puts his wrapper on. Same thing efest have done. They are not fake.

 

[Zegee]

Gonna get me some popcorn this is gonna be a page Turner

 

[M4dm0nk3y]

@M4dm0nk3y Thanks so much for the measurements! With a 0.32ohm build on a fresh battery (4.2V) you are aiming to see current of I = V/R = 4.2/0.32 = 13.125A.

View attachment 9547

From the above graph of the red efest 26650 batteries, graph from http://lygte-info.dk/review/batteries2012/Efest IMR26650 3000mAh (Red) 2014 UK.html , and working from somewhere around the 0,5Ah portion of the graph (battery might have lost a bit of capacity, not fully fully charged, etc) you're looking at getting a max of 3.55V out of it. Accounting for the battery having been put through quite a few cycles and we're looking at even worse performance, then of course there are losses from the mech mod itself as well as the tobh atty, etc and we start to see where numbers like 2.8V under load come from!



I would put money on the higher voltage to atty measured here being mostly due to the much higher quality VTC5 battery and not mostly due to the different mod used.



@Andre , although it is repeated over and over by the vaping community, this "voltage drop" figure is actually only meaningful if quoted along with the specific battery used (as well as age/condition and resting voltage) and the ohm load being driven. I don't mean to offend anyone here, I just want to get the right info out there.

There is actually no such thing as a "voltage drop", all that is happening is that we can measure a drop in the voltage, which is caused by a current flowing through a resistance (mod/battery internal resistance/resistance through 510 connector etc), the only meaningful figures would be resistances of each part of the chain (battery, atty, coils, mod) but this is extremely hard to break down.

If it seems hard to accept that there is no meaning to "voltage drop" you can test it easily by taking your Reo, putting an atty with a low resistance (say 0.3 or 0.4ohm) on and measuring voltage while firing, then put an atty with a high resistance (say 1ohm or 2ohm) and measure voltage while firing again. You will see two totally different readings, hence no meaning to "voltage drop" without more information.

Thanks for all the info! Seems it's almost time for some new batteries then - sub-ohming at such a low resistance for a couple of months really take their toll on batteries; oh well, they're cheap enough at least

 

[M4dm0nk3y]

Came across the following article explaining voltage drop under load, it's an interesting read and explains it well: http://www.vape-break.com/2013/05/explained-under-load-voltage-drop/

It's very much dependant on resistance of the coil

If I interpret this article correctly, my calculations come out like so (please feel free to help me out if I'm mis-interpreting something here):

Total Resistance = Mod Resistance + Internal Battery Resistance + Coil Resistance an Atty
I = (Battery Voltage) / (Total Resistance)
I = 4.2 / (0.05 + 0.06 + 0.32)
I = 9,767 amps

Voltage (Coil) = I x R (Coil)
Voltage (Coil) = 9,767 x 0.32
Voltage (Coil) = 3,12 Volts

Voltage (Drop) = Voltage Resting - Voltage (Coil)
Voltage (Drop) = 4.2 - 3,12
Voltage (Drop) = 1,08 Volts

 

[capetocuba]

Not All Efest are re wrapped. The trick to getting the genuine batteries, both Efest and Sony VTC's is to know the batteries original real world purpose and then have a connection within specific industry, to get the batteries. Very tricky, many muppets cannot get the originals.

I take exception to you calling people muppets. That implies that I am a muppet too as I may have purchased from them.

 

[1am7h30n3]

If I interpret this article correctly, my calculations come out like so (please feel free to help me out if I'm mis-interpreting something here):

Total Resistance = Mod Resistance + Internal Battery Resistance + Coil Resistance an Atty
I = (Battery Voltage) / (Total Resistance)
I = 4.2 / (0.05 + 0.06 + 0.32)
I = 9,767 amps

Voltage (Coil) = I x R (Coil)
Voltage (Coil) = 9,767 x 0.32
Voltage (Coil) = 3,12 Volts

Voltage (Drop) = Voltage Resting - Voltage (Coil)
Voltage (Drop) = 4.2 - 3,12
Voltage (Drop) = 1,08 Volts

@M4dm0nk3y that looks pretty cool, where did you get the values of 0.05, 0.06 from, are those assumed values copied from the article?

I did something sort of similar. I lumped mod and battery internal resistance together.



Where EMF and Vload are known, EMF being battery resting voltage and Vload being voltage measured at atty while firing.
Rinternal (in the picture) will represent mod and battery internal resistance.
Rload will represent the atty/coil resistance.

We can use the voltage divider formula:
Vload = EMF x Rload / (Rload + Rinternal)

Solving for Rinternal:
Rinternal = (Rload x (EMF - Vload))/Vload
Rinternal = (0.4 x (4.06 - 3.1))/3.1 = 0.124ohm

Ok, so here is my proposal. We know that the batteries have continuous discharge rating of 15A, red efest 26650, so if we propose a build right on the safety limit of (continuous - remember pulse is still higher so we have "safety" maybe lol built in) 15A we can do a 0.28ohm build, that's 0.28ohm total resistance. So we need to build a 0.28 - 0.124 = 0.156ohm coil. This should net us an atty/coil
power = I x I x R = 15 x 15 x 0.156 = 35.1W.

Ok so that might be a bit close to the limit, but this math should work for any build, and will get us closer to a "power to the coil" build instead of the build's we've been doing where we plan for a certain wattage to the coils and wind up with only a fraction of it...

Thoughts?

 

[Chop007]

I take exception to you calling people muppets. That implies that I am a muppet too as I may have purchased from them.

Only a joke dude. I would never use dodgy batteries in a mech mod. Muppets are cute anyways. Apologies for calling people Muppets.......really...... I never said those who purchased dodgy batteries are muppets, I said those who cannot expend the effort to get the genuine article for their loyal clients, are muppets. So, no, you are not a muppet.

P.S. I LOVE MUPPETS........

 

[Chop007]

Sorry to do this but really? Did you go and research we even supplied links, slating the other retailers calling them muppets was a bit uncalled for. As far as I can tell no one in SA has been selling "fake" Efests. Everyone here has been trying to tell you that efest are rewrapping cells from other manufacturers , much in the way that AW does. AW does not manufacture he sources cells tests the batch to make sure it is capable of the current drain and then puts his wrapper on. Same thing efest have done. They are not fake.

I never slated any retailers. I simply said that it is possible to get the real deal in and that there are fakes/re wrapped batteries on the market. We go to great lengths to get the real batteries in and the inference that all Efest batteries are simply re wrapped LG's is simply not true.

Anyways, sorry about the Muppet comment, really, I never thought anyone would take offense to 'Muppets' seriously......I shall refrain from calling anyone, even those who are not named but rather implied....Muppets...in the future. Hope you can forgive me for calling unknown possible sellers of real, maybe not fake, rewrapped, battery suppliers......, muppets. I love muppets anyways.

P.S. On second thoughts, my intentions where not derogatory. Simply a silly comment, I will not get drawn into a pointless flame war about Muppets, I have better things to do with my time and many clients to assist. If anyone takes exception to my Muppet comment, you have my apology. Furthermore I have nothing to say on the subject. So put the popcorn away.

 

[Zegee]

 

[capetocuba]

 

[Gazzacpt]

I never slated any retailers. I simply said that it is possible to get the real deal in and that there are fakes/re wrapped batteries on the market. We go to great lengths to get the real batteries in and the inference that all Efest batteries are simply re wrapped LG's is simply not true.

Anyways, sorry about the Muppet comment, really, I never thought anyone would take offense to 'Muppets' seriously......I shall refrain from calling anyone, even those who are not named but rather implied....Muppets...in the future. Hope you can forgive me for calling unknown possible sellers of real, maybe not fake, rewrapped, battery suppliers......, muppets. I love muppets anyways.

P.S. On second thoughts, my intentions where not derogatory. Simply a silly comment, I will not get drawn into a pointless flame war about Muppets, I have better things to do with my time and many clients to assist. If anyone takes exception to my Muppet comment, you have my apology. Furthermore I have nothing to say on the subject. So put the popcorn away.

Reading your post I realised that you never read the previous posts properly and didn't look at any links provided by this community or those on ECF.

 

[Andre]

Reading your post I realised that you never read the previous posts properly and didn't look at any links provided by this community or those on ECF.

Agree, and not responding to those posts. Getting the community riled up by not addressing substance does not do VapeMob any favours.

 

[Zegee]

ok for the purpose of all parties involved sanity will a mod please lock this thread we are at a point where we are chasing our tails.
can't we all just get along

 

[Andre]

ok for the purpose of all parties involved sanity will a mod please lock this thread we are at a point where we are chasing our tails.
can't we all just get along

Noooo, @Zegee and you were the one getting out the popcorn. I love @Chop007 and get along with him perfectly, I just do not agree with his arguments. And I think all of us has been very civilized in our discourse. And this thread addresses some vital safety issues, which should be open for any queries.

 

[Zegee]

Noooo, @Zegee and you were the one getting out the popcorn. I love @Chop007 and get along with him perfectly, I just do not agree with his arguments. And I think all of us has been very civilized in our discourse. And this thread addresses some vital safety issues, which should be open for any queries.

I hear you andre it just didn't seem to be going anywhere , I have no issue with anyone and it's more a case of before things get nasty cut it off.but be that as it may if we can all agree to remain civilised I'm sure we will be ok.

Lol I was instructed to put popcorn away so I decided to get biltong , In it for the long haul.

On a more serious note this may only be truly resolved with independent research conduct by us for us.

Maybe we can look at starting this project as it may prove fruitful for our community . I for one have been mislead by other reviews claiming the greatness and awesomeness of some products.

Just a thought , I may be loosing it as I haven't eaten yet so if I am I apologise

 

[1am7h30n3]

ok for the purpose of all parties involved sanity will a mod please lock this thread we are at a point where we are chasing our tails.
can't we all just get along

Please don't lock this thread, I feel like me and @M4dm0nk3y are making some interesting progress...

 

[Zegee]

Noooo, @Zegee and you were the one getting out the popcorn. I love @Chop007 and get along with him perfectly, I just do not agree with his arguments. And I think all of us has been very civilized in our discourse. And this thread addresses some vital safety issues, which should be open for any queries.

I hear you andre it just didn't seem to be going anywhere , I have no issue with anyone and it's more a case of before things get nasty cut it off.but be that as it may if we can all agree to remain civilised I'm sure we will be ok.

Lol I was instructed to put popcorn away so I decided to get biltong , In it for the long haul.

On a more serious note this may only be truly resolved with independent research conduct by us for us.

Maybe we can look at starting this project as it may prove fruitful for our community . I for one have been mislead by other reviews claiming the greatness and awesomeness of some products.

Just a thought , I may be loosing it as I haven't eaten yet so if I am I apologise

Please don't lock this thread, I feel like me and @M4dm0nk3y are making some interesting progress...

Ok sorry It was a bit premature

Thank goodness I am not a moderator

Have at it guys

 

[Andre]

I hear you andre it just didn't seem to be going anywhere , I have no issue with anyone and it's more a case of before things get nasty cut it off.but be that as it may if we can all agree to remain civilised I'm sure we will be ok.

Lol I was instructed to put popcorn away so I decided to get biltong , In it for the long haul.

On a more serious note this may only be truly resolved with independent research conduct by us for us.

Maybe we can look at starting this project as it may prove fruitful for our community . I for one have been mislead by other reviews claiming the greatness and awesomeness of some products.

Just a thought , I may be loosing it as I haven't eaten yet so if I am I apologise

No independent research required for resolution of this matter at all. The 2 matters of substance, which are unanswered imo are simply:

1. The assertion that not all Efests are re-wrapped: This might be a simple matter of definition. Fact is Efest does re-wrap batteries in the sense of wrapping their own labels over those of the original manufacturer - this does not seem to be in dispute. However, Efest also re-wraps in the sense of only buying batteries from other manufacturers and putting their own wrapping on such batteries. They buy the batteries bare (no wrapping) or the buy it with the wrapping of the original manufacturer and then either remove same or wrap over it. Efest is not a manufacturer of batteries. Can we all agree with the content of this paragraph?
2. The assumption that we have said Efest batteries are fake: Our assertion simply was that Efest has misleading statements on their batteries, e.g. the 35A on their purple 18650 2500mAh battery does not refer to Continuous Discharge Current (which is the important indicator for vapers). The CDC of this battery is actually 20A, which Efest has now publicly admitted. This, for example, is important for all vapers to know, but even more important for vendors to know, acknowledge and publish. Anyone disagree with this paragraph?

 

[Gazzacpt]

No independent research required for resolution of this matter at all. The 2 matters of substance, which are unanswered imo are simply:

1. The assertion that not all Efests are re-wrapped: This might be a simple matter of definition. Fact is Efest does re-wrap batteries in the sense of wrapping their own labels over those of the original manufacturer - this does not seem to be in dispute. However, Efest also re-wraps in the sense of only buying batteries from other manufacturers and putting their own wrapping on such batteries. They buy the batteries bare (no wrapping) or the buy it with the wrapping of the original manufacturer and then either remove same or wrap over it. Efest is not a manufacturer of batteries. Can we all agree with the content of this paragraph?
2. The assumption that we have said Efest batteries are fake: Our assertion simply was that Efest has misleading statements on their batteries, e.g. the 35A on their purple 18650 2500mAh battery does not refer to Continuous Discharge Current (which is the important indicator for vapers). The CDC of this battery is actually 20A, which Efest has now publicly admitted. This, for example, is important for all vapers to know, but even more important for vendors to know, acknowledge and publish. Anyone disagree with this paragrap?

That pretty much sums it up Oom @Andre. Very eloquent.

 

[M4dm0nk3y]

@M4dm0nk3y that looks pretty cool, where did you get the values of 0.05, 0.06 from, are those assumed values copied from the article?

I did something sort of similar. I lumped mod and battery internal resistance together.

View attachment 9623

Where EMF and Vload are known, EMF being battery resting voltage and Vload being voltage measured at atty while firing.
Rinternal (in the picture) will represent mod and battery internal resistance.
Rload will represent the atty/coil resistance.

We can use the voltage divider formula:
Vload = EMF x Rload / (Rload + Rinternal)

Solving for Rinternal:
Rinternal = (Rload x (EMF - Vload))/Vload
Rinternal = (0.4 x (4.06 - 3.1))/3.1 = 0.124ohm

Ok, so here is my proposal. We know that the batteries have continuous discharge rating of 15A, red efest 26650, so if we propose a build right on the safety limit of (continuous - remember pulse is still higher so we have "safety" maybe lol built in) 15A we can do a 0.28ohm build, that's 0.28ohm total resistance. So we need to build a 0.28 - 0.124 = 0.156ohm coil. This should net us an atty/coil
power = I x I x R = 15 x 15 x 0.156 = 35.1W.

Ok so that might be a bit close to the limit, but this math should work for any build, and will get us closer to a "power to the coil" build instead of the build's we've been doing where we plan for a certain wattage to the coils and wind up with only a fraction of it...

Thoughts?

Very interesting! I'm sitting here scratching my head trying to make sense of it all. Yes I assumed those two values, just theoretical values for now (I am definitely going to go get myself a multimeter)

Ok, so this is how I broke it down:

Known values:
EMF = Battery resting voltage
Rload = The atty/coil resistance

Calculated Values:
Vload = Voltage measured at atty while firing
Rinternal = Mod and battery internal resistance
Iload = Current in circuit under load
Pcoil = Power at coil while firing

Formulas for calculated values:
Vload = (EMF x Rload) / (Rload + Rinternal)
Rinternal = (Rload x (EMF - Vload))/Vload

Sample Situation
================
Assume:
EMF = 4.2V (freshly charged)
Rload = 0.156 ohm

Solving for Vload:
Vload = (EMF x Rload) / (Rload + Rinternal)
Vload = (4.2 x 0.156) / (0.156 + 0.1)
Vload = 0.6552 / 0.256
Vload = 2.5594 V

Solving for Rinternal:
Rinternal = (Rload x (EMF - Vload)) / Vload
Rinternal = (0.156 x (4.2 - 2.5594)) / 2.5594
Rinternal = 0.2559336 / 2.5594
Rinternal = 0.099 Ohm

Proposal (Here there is some discrepancy, and I'm not sure why)
========
Iload = EMF / (Rinternal + Rload) (I = V / R)
Iload = 4.2 / (0.099 + 0.156)
Iload = 16,47 Amps (!)

Pcoil = Iload x Vload (W = Amps x Voltage) -> Here I assumed that Amps is Amperage under load, and Voltage is voltage under load
Pcoil = 16,47 x 2.5594
Pcoil = 42,154 W


How did you get to this calculation?: power = I x I x R = 15 x 15 x 0.156 = 35.1W.