When building coils for much should I calculate for 4.2a or 3.7? Sony vtc5
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Use 4.2 for safety, and 3.7 for bragging rights.
You don't need another confirmation here, but just to put the "why" into it, 4.2 volts corresponds to the maximum current (amps) draw available from your battery (whatever that may be based on your coil's resistance). Amp drain only decreases on a mech during use, so if you are safe at full charge, you're safe anywhere below it. All assuming a stable build, no shorts, etc.
[EDIT] Personal tip: once you start to really understand the coils you like and start honing them to your preferences, you may do what I like to do, which is to build just a tad rowdier than I enjoy. Juuuuuust a tad. Your battery won't vape at 4.2 for long at all before settling to about 4.0-3.9V, and I've found that you can really milk a battery's sweet spot if you build your coils around it.
Short version: calculate for 4.2, BUILD for 3.9.
[EDIT] Personal tip: once you start to really understand the coils you like and start honing them to your preferences, you may do what I like to do, which is to build just a tad rowdier than I enjoy. Juuuuuust a tad. Your battery won't vape at 4.2 for long at all before settling to about 4.0-3.9V, and I've found that you can really milk a battery's sweet spot if you build your coils around it.
Short version: calculate for 4.2, BUILD for 3.9.
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Yes those things haha long day..volts?
I must be out of touch.
24ga ss116L two cores outer is 32 22ga ss116L. 6 wraps. It rips like crazy haha only 75w on my regulated mod. Flavor and vapor density are a lot better than most multiple coil setups I have built.
So When I calculate at 4.2 and I get 20.01 haha am I playing with fire? I have not surpassed 16a on any of my builds I have put on my mech since it is single cell
You determine your build's target resistance according to the battery's amp rating (continuous discharge rate) that you will be using on a mech. Never exceed the amp draw of your battery.
Your Sony VTC5A has a CDR of 25 amps. So you will not be exceeding the amp rating of that specific battery.
Everyone is free to set their own safety parameters, and I can only say what mine are.
I try to never exceed 50% of the CDR (continuous discharge rating) of a fully charged battery (4.2v). So with the 20A batteries that I use, that would be 10A. The Ohm's Law Calculator tells me that a .4 ohm build is as low as I would want to use on a mech.
The reason that I place a 50% limit is because as a battery ages the mAh of the battery degrades, as the mAh degrades so does the batteries c rating (amp limit). So down the road, your 20A battery may only be a 10A battery.
It really does pay off using a margin of safety concerning resistance. A couple of years ago I was happily vaping away with a 0.6 ohm build on my mech. Out of the blue, my vape became extremely harsh. I stopped vaping it immediately and began diagnostic steps. First off, I measured the resistance of my atty. It measured 0.1 ohm -- a drop of 0.5 ohms. What had happened was the post screw for one end of the coils had become loose. I tightened the screw and remeasured the resistance. 0.6 ohm.
Had I not had that margin of safety, that 0.5 ohm drop would have caused a hard short. My battery likely would have vented. Luckily my mechanical has proper ventilation holes, so it would not become a pipe bomb should the battery have vented. Does your mech have proper ventilation?
Mech Mods with top venting holes?
Did the post screw short out against the topcap or body of the atomizer? Otherwise, I don't see how loosening a connection would drop the resistance. Wouldn't it increase it?
I don't think it's a linear relationship. Had you been using a .3 build, do you think it would have still lost .5 and gone negative when the screw became loosened? .1 may well have just been the resistance of the atomizer body itself if the positive screw shorted to the negative topcap/body when it became loose, and bypassed the coil.
I'm not trying to start a fight, I just legitimately don't understand how a good solid connection is going to introduce more resistance compared to an iffy one. A better connection should increase conductivity, not lessen it.
(Also I don't mean to discount the idea of having a safety margin. I just think in this case, it might not be that what saved your skin, so much as that you just noticed the problem right away and didn't continue driving the battery that hard for any length of time.)
(Also also, note that CDR is determined to provide best battery life over time and, as such, already has a significant safety margin built right in. You can actually safely use draws higher than this [see Mooch's MVA - max vaping amps] without issues other than shortened battery life, and potential burns if you touch the hot cells [MVA allows the cells to reach no higher than 100C -- 212F -- during continuous discharge, which is still really hot, but should not make them go POP.])
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OK. Wait a minute. Are you asking if you should use 4.2 Volts and the resistance of your wire in Ohms to discover the load in Amps that you are generating?
So the Sony vtc5 is supposedly 25comstsnt discharge but i have read elsewhere it's 20a. Regardless I'm staying under 20a on my builds. When I calculate my coils on the app I use it asks for the power of the battery and I have been putting in 4.2 because that is the full charge voltage
OK. So when you are using the app to make sure that you are staying within the safety limits of the battery, you are using 4.2 Volts because that's where a freshly charged 18650 starts. Sounds good.
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