So I was sitting here thinking about amp draw in regards to sub-ohm. So here is the set up....... .4-.5 ohm with a fresh battery. So for amps it's something like 4.2v/.4ohm= 10.5 amp draw. Now here is my question when calculating amp draw do I go by what the battery voltage or the voltage under load (re: what it would read with an inline meter under the .4 ohm load) any one has any info I'd be glade to hear it.
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While, 10 amps is the limit on most of the decent batteries, it is not something I would experiment with. You really should go above 8 amps with a batt that has a 10 amp limit.
While it is true you are probably not getting the full 4.2 volts to your atty, you should just buy batteries with higher amp limits, rather than pushing the ones you already have.
Lastly, is the vape at .4 ohms that much better than .6? Srsly...
While it is true you are probably not getting the full 4.2 volts to your atty, you should just buy batteries with higher amp limits, rather than pushing the ones you already have.
Lastly, is the vape at .4 ohms that much better than .6? Srsly...
Thanks for the input. So what I get from what you are saying is, that you indeed measure from what is going to the Atty? Also for the way I like to vape (about 1/2 second rips) at .4 if get an instant response. Where at .6 it takes that 1/2 second to get going. I know it sounds like splitting hairs but it's just how I like to vape. To each his own. But again thanks for the info.
Oh thought I should add I'm already using mnke batts. So it's not a safty issue I know I'm vaping safe this is just a curiosity.
Hey, scabs. You want to use the full battery voltage. Although you lose voltage to your mod (v-drop), you are still asking the battery for it, just not vaping it.
Sweet. So far that's how I've been doing my math just to be on the safe side. I'll never do a .2 coil (unless I feel frisky and do a quad coil on the Helios) so I shouldn't ever come close to the Max amp of my battery. Thanks for the answer. I hate it when I don't know something I think I should lol!
there is going to be V drop in whatever MOD you use.....a fully charged battery on my mod puts out 3.6V and 3.9 on another......but to be safe get some good batteries....
AW IMR
18650 1600mah 24A
MNKE IMR
18650 1500mah 20A
Orbtronic
18650 SX22 (hybrid) 2000mAh 22A
Samsung hybrid
INR18650-20R 2000mah 22A
Sanyo hybrid
UR18650EX 2000mAh 20A
Sony
us18650vct3 (hybrid) 1600mAh 30A
EH IMR
18650 2000 mAh 16A
18650 1500 mAh 22A
Efest IMR
18650 1600mAh 30A
just in case you have these as well and didn't know the specs.....sorry if you did already........
AW IMR
18650 2000mah 10Amp CDR
18490 (1100mah) 8.8A (16.5A?)
18350 (700mah) 6A
Panasonic or Orbtronic hybrid
CGR18650CH (IMR/hybrid) 2250mAh 10A
NCR18650PF (LiNiCOMnO2) INR/ICR/IMR Hybrid 2900mAh 10A
NCR18650PD (LiNiCoAl) 2900mAh 10A
Samsung hybrid (LiNiCoMnP)
INR18650-22P 2200mAh 10A
Sony
us18650v3 IMR 2250mAh 10A
EH IMR
18650 2000 mAh 16A
18500 1100 mAh 8.8A
18350 800 mAh 6.4A
Efest IMR
18650 (IMR/hybrid) 2250mAh 10A
18650 2000mAh 10A
18490 1100mah 8.8A
18350 800mah 6.4A
AW IMR
18650 1600mah 24A
MNKE IMR
18650 1500mah 20A
Orbtronic
18650 SX22 (hybrid) 2000mAh 22A
Samsung hybrid
INR18650-20R 2000mah 22A
Sanyo hybrid
UR18650EX 2000mAh 20A
Sony
us18650vct3 (hybrid) 1600mAh 30A
EH IMR
18650 2000 mAh 16A
18650 1500 mAh 22A
Efest IMR
18650 1600mAh 30A
just in case you have these as well and didn't know the specs.....sorry if you did already........
AW IMR
18650 2000mah 10Amp CDR
18490 (1100mah) 8.8A (16.5A?)
18350 (700mah) 6A
Panasonic or Orbtronic hybrid
CGR18650CH (IMR/hybrid) 2250mAh 10A
NCR18650PF (LiNiCOMnO2) INR/ICR/IMR Hybrid 2900mAh 10A
NCR18650PD (LiNiCoAl) 2900mAh 10A
Samsung hybrid (LiNiCoMnP)
INR18650-22P 2200mAh 10A
Sony
us18650v3 IMR 2250mAh 10A
EH IMR
18650 2000 mAh 16A
18500 1100 mAh 8.8A
18350 800 mAh 6.4A
Efest IMR
18650 (IMR/hybrid) 2250mAh 10A
18650 2000mAh 10A
18490 1100mah 8.8A
18350 800mah 6.4A
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Nice info, Krazirob, buyer of Grands when wife looks at you funny (I'na hafta try that sometime). This one tests out at more like 7A.
thanks....ill change that then for my records....i tend to stay away from the bottom list......i rather have a battery capable of more power than not enough.....especially since i use them on sub ohm coils as well as 1.1 - 1.3 coils.....
Yeah she looked at my even more funny when i had two packages arrive......lol......so ill be taking a trip to the coach store this weekend......HAHA
Yeah she looked at my even more funny when i had two packages arrive......lol......so ill be taking a trip to the coach store this weekend......HAHA
I get the reasoning behind the safety "buffer" of figuring current using 4.2V, but I wholly disagree with that method. I've always been an advocate that you should know exactly what is happening in you mod. That method is OK if you you are trying to figure out what resistance would be in the "safe" range, but if it's already built you should know with a reasonable measure of accuracy how it is performing.
For that reason....to ACCURATELY calculate the current demand from the battery you should measure the voltage at the atty posts and divide that by your coil resistance. Once you know the true current, you can adjust to suit your balance of safety and performance.
For that reason....to ACCURATELY calculate the current demand from the battery you should measure the voltage at the atty posts and divide that by your coil resistance. Once you know the true current, you can adjust to suit your balance of safety and performance.
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Really? I had surmised, from my own experiments, that the voltage measured at the atty posts wasn't necessarily indicative of what was being drawn from the battery. When I made improvements to my device, was I not getting rid of unwanted "resistance" that was wasting some of the current? I thought that v-drop (as separate from battery's internal resistance) was indicative of current being drawn but not getting to the atty. Thanks for any clarification, Rader.
As for 4.2, well I figure it at my actual charge level.
As for 4.2, well I figure it at my actual charge level.
Nice numbers @krazirob!
@rader from what I understand about what your saying is.....an in line meter under load isn't fully accurate? And btw I love it to find other people to be as nit picky about e-cigs as I am.
@rader from what I understand about what your saying is.....an in line meter under load isn't fully accurate? And btw I love it to find other people to be as nit picky about e-cigs as I am.
You were getting rid of unwanted resistance, but it wasn't nessisarily wasting current. Wasting power...yes. The current is just reduced due the the unwanted resistance. Current supplied by the battery is dependent on the total resisistance of the complete circuit, and the circuit can be divided into: Battery resistance, material and contact resistance (mod and atty), and coil resistance. Eliminate some of the contact resistance and you increase the current through the circuit and decrease the voltage drop.
Here's a spreadsheet that might help...
https://www.dropbox.com/s/rqvj5anfq1cg1ia/V Drop Calc.xlsx
An inline meter can get you close, but I don't like them because they are also adding resistance to the total circuit. Meaning that the current through the circuit without the meter will be HIGHER than what you calculate with the meter.
The efest 18650 2000 mah info is wrong. I keep seeing people post it as a 10a but when I do the math i come up with 20 amp. So to be absolutely sure i emailed efest to get the specs direct from them. Here is the response
Thanks for your kind enquiry. This is Kiko from Efest company.
For Efest IMR 18650 2000mah battery, the C rating is 10C. Max discharge rating is 20A.
Hope help you know more about our products
If you have any other questions, feel free to let me know.
Best regards,
Kiko
So just for fun today I'm going to meter at the posts to see what i get. Still want an in line just for ghit & shiggles. Thanks for all the input guys, im getting into higher end mechs and wanna see if all the diffrent contacts really do makeuch of a difference
lol I'm never going to get anything done at work today playing with my new Cronus.......
Better is subjective but the difference between .4 and .6 ohm on an unregulated mod is profound. That's upwards of a 50% difference in power at vaping voltages.
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