Battery/Ohms Question

[graykev]

Hi,

I've been vaping 316 duel SS claptons in my rx200 using my VCMT for months now. The ohms comes in at 0.15 and i have the wattage set at 70w but in TC mode (I change the temp frequently depending on how much of a hit i want).

I have noticed my batteries are not lasting as long as before when i vaped at around 0.3 - 0.5ohm. I would expect this but this made me read into things a little more. My findings (may be wrong) tell me that based on my setup, I am running extremely close to my batterys amp limit (LG HG2 18650 battery 20A continuous load, 3000mAh).

Is this really the case? Should I switch to higher ohms coils?

Any advice would be great as I want to be safe and won't relax until I have some expert advice.

Thanks,
Kevin.

 

[conanthewarrior]

(EDIT: I should of noticed you are using a RX200-my bad. Please take note if you have increased wattage, are using thicker wire, or coils that have a longer ramp up time-this could well be the answer without reading everything)

What wattage was you using the higher resistance coils at?

Often this is a large factor, people use much lower resistance coils, that use thicker wire, so use more power.

A 0.2 or 2 Ohm coil will pull the same amps from your battery, at the same wattage. There is a huge error by quite a few regulated mod users that resistance plays a factor in Amp load-in a mech this is very true, with a regulated mod, wattage is your determining factor.

When you was using 0.5 Ohm coils, what gauge was the wire? It may of had less of a ramp up time-and this is now being noticed by diminished battery life.

To work out amp load on your regulated mods, take the batteries voltage PRE board, so for a dual 18650 mod at full charge, 8.4V.
Then you take the wattage-and divide the wattage by the pre board voltage.

70/8.4=8.33A. Then take into account mod efficiency, I use 90% if I am unsure, so that calculation, then divided by 0.9 for the 90%, =9.25A.

This shows how dual 18650 devices achieve higher power safely-higher voltage, lower amps. It also explains how regulated mods can safely fire at 0.05Ohms-resistance does not determine amp load, wattage does. (This is converted by the board to the wattage you desire though-this is after it has taken the power from the batteries though, either bucking or boosting the voltage).

As actual battery voltage falls, amp draw increases.

If you are using a single battery mod though, at 4.2V you will be pulling 16.6A, count in efficiency again and you are pulling 18.51A.
As voltage falls, near cut off at 3.35V, you are pulling just over your batteries CDR, at 20.89A. 23.2 after efficiency is taken into consideration.

I would look at wire gauge, have you increased wattage, and all of those before you return to higher resistance-unless of course, you prefer higher resistance and want to go back it it .

 

[graykev]

(EDIT: I should of noticed you are using a RX200-my bad. Please take note if you have increased wattage, are using thicker wire, or coils that have a longer ramp up time-this could well be the answer without reading everything)

What wattage was you using the higher resistance coils at?

Often this is a large factor, people use much lower resistance coils, that use thicker wire, so use more power.

A 0.2 or 2 Ohm coil will pull the same amps from your battery, at the same wattage. There is a huge error by quite a few regulated mod users that resistance plays a factor in Amp load-in a mech this is very true, with a regulated mod, wattage is your determining factor.

When you was using 0.5 Ohm coils, what gauge was the wire? It may of had less of a ramp up time-and this is now being noticed by diminished battery life.

To work out amp load on your regulated mods, take the batteries voltage PRE board, so for a dual 18650 mod at full charge, 8.4V.
Then you take the wattage-and divide the wattage by the pre board voltage.

70/8.4=8.33A. Then take into account mod efficiency, I use 90% if I am unsure, so that calculation, then divided by 0.9 for the 90%, =9.25A.

This shows how dual 18650 devices achieve higher power safely-higher voltage, lower amps. It also explains how regulated mods can safely fire at 0.05Ohms-resistance does not determine amp load, wattage does. (This is converted by the board to the wattage you desire though-this is after it has taken the power from the batteries though, either bucking or boosting the voltage).

As actual battery voltage falls, amp draw increases.

If you are using a single battery mod though, at 4.2V you will be pulling 16.6A, count in efficiency again and you are pulling 18.51A.
As voltage falls, near cut off at 3.35V, you are pulling just over your batteries CDR, at 20.89A. 23.2 after efficiency is taken into consideration.

I would look at wire gauge, have you increased wattage, and all of those before you return to higher resistance-unless of course, you prefer higher resistance and want to go back it it .

Conan - Thanks so much for taking the time to explain all this. You know your stuff!!

Before switching to SS I was always using micro kanthal coils at 27g coming out at around 1.0 ohms (0.5 duel setup). I only went upto around 30 - 40w.

My SS duel claptons end up at 0.15ohm but i'm unsure of the exact thickness as i buy them pre-made. Wattage currently at 70w. The vape I get from them is perfect and ideally i wouldn't want to change. The only reason I would is if I had to due to this setup stressing my batteries to unsafe levels.

So you reckon this setup is safe? I chain vaped last night and then felt the batteries and they felt normal temp. Nothing concerning but when reading some calculations, some say i'm drawing far more current that the 'safe' 20A. But if this is somehow being dealt with by my regulated device and keeping me safe, i'm happy to continue as I am?

 

[conanthewarrior]

Conan - Thanks so much for taking the time to explain all this. You know your stuff!!

Before switching to SS I was always using micro kanthal coils at 27g coming out at around 1.0 ohms (0.5 duel setup). I only went upto around 30 - 40w.

My SS duel claptons end up at 0.15ohm but i'm unsure of the exact thickness as i buy them pre-made. Wattage currently at 70w. The vape I get from them is perfect and ideally i wouldn't want to change. The only reason I would is if I had to due to this setup stressing my batteries to unsafe levels.

So you reckon this setup is safe? I chain vaped last night and then felt the batteries and they felt normal temp. Nothing concerning but when reading some calculations, some say i'm drawing far more current that the 'safe' 20A. But if this is somehow being dealt with by my regulated device and keeping me safe, i'm happy to continue as I am?

That is OK mate-I still have a lot to learn, I feel we always keep learning if I am honest.

Ok, that would explain the battery life difference, 30-40W is pulling a lot less than 70W from your batteries.

Also-I mean this nicely BTW, if you had two 0.5 coils, they actually half their resistance-so 0.25 Ohms. I may of misread what you was stating though, if so, sorry.

Claptons will definitely have a longer ramp up than 27G coils, and as you have noticed, require more power. In essence, no, it is not stressing your batteries past unsafe levels-0.15 in a mech would be though with what you are using (Some people do build this low with those batteries in a mech, but I can't myself recommend exceeding the CDR of a battery-especially LG HG2's-they are fine for your use though).

Yes, it is safe. I can link you to some places where I got my calculations from, along with explanations on how regulated devices work incase you are worried.
You are not drawing more than your batteries can handle, at 70W, in a triple 18650 configuration. You have most likely read that you are overdrawing your batteries from Ohm's law calculations-which are applicable if you want to hit maximum wattage as a lot of regulated devices need a build within 'band' to hit their full power, but NOT for calculating amp load on a VW reg.
You are nowhere near this though, your batteries are not getting warm/hot as you have experienced-they can get very hot when overstressed severely, such as in a dead short in a mech, which can lead to catastrophic failure.

But, at 70W, with your dual clapton's, there will be a hit on your battery life as you have doubled the watts you are using-but, if you prefer this setup, there is no reason not to stick with it-as your regulated mod is doing exactly what it should, regulating your vape.

 

[graykev]

That is OK mate-I still have a lot to learn, I feel we always keep learning if I am honest.

Ok, that would explain the battery life difference, 30-40W is pulling a lot less than 70W from your batteries.

Also-I mean this nicely BTW, if you had two 0.5 coils, they actually half their resistance-so 0.25 Ohms. I may of misread what you was stating though, if so, sorry.

Claptons will definitely have a longer ramp up than 27G coils, and as you have noticed, require more power. In essence, no, it is not stressing your batteries past unsafe levels-0.15 in a mech would be though with what you are using (Some people do build this low with those batteries in a mech, but I can't myself recommend exceeding the CDR of a battery-especially LG HG2's-they are fine for your use though).

Yes, it is safe. I can link you to some places where I got my calculations from, along with explanations on how regulated devices work incase you are worried.
You are not drawing more than your batteries can handle, at 70W, in a triple 18650 configuration. You have most likely read that you are overdrawing your batteries from Ohm's law calculations-which are applicable if you want to hit maximum wattage as a lot of regulated devices need a build within 'band' to hit their full power, but NOT for calculating amp load on a VW reg.
You are nowhere near this though, your batteries are not getting warm/hot as you have experienced-they can get very hot when overstressed severely, such as in a dead short in a mech, which can lead to catastrophic failure.

But, at 70W, with your dual clapton's, there will be a hit on your battery life as you have doubled the watts you are using-but, if you prefer this setup, there is no reason not to stick with it-as your regulated mod is doing exactly what it should, regulating your vape.

Perfect mate! Thanks again. This has put my mind at ease and also means I can stick to my SS claptons