I have started using a mech mod and I noticed my batteries (sony vtc4) are getting black dots at the minpole. They seem to be permanent, but I haven't tried to wipe them off with acetone or something yet, so I'm not sure. Im using parallel ni80 coils rated at 0.14 ohms. Maybe the batteries are getting those black spots because of the high discharge speed they're going through? Im using a vgod pro mech 2, which has the tricon switch with small 3 pins instead of 1 big pin that connects to the minpole of the battery, maybe that's the reason? Has anyone encountered something like this before?
Battery getting black dots at minpole
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No I have not, but I don't use mechs and I'm not exactly and expert on them, either.
Those sort of look like it might be the result of arcing, but I'm not 100% sure, nor am I 100% sure why they'd occur there (unless you are inserting the positive end first, in which case it could be arcing from where the tube of your mod's threads are meeting the RDA or whatever you are using up there, in which case the solution could be lubricating your threads (or so I hear). Whatever it is, I'd say hang on until an actual expert can tell you more. I'd imagine you don't want that to be happening.... And the solution could be any number of things I don't know enough to explain.
I just wanted to say.... It's Easter... Wait until you've got the right solution from some experienced mech users, given small things can cause (or be symptomatic of bigger things) big problems.
Welcome to ECF. Hope any of the above is helpful; it probably isn't. But, do wait for someone more expert to come along.
Anna
Those sort of look like it might be the result of arcing, but I'm not 100% sure, nor am I 100% sure why they'd occur there (unless you are inserting the positive end first, in which case it could be arcing from where the tube of your mod's threads are meeting the RDA or whatever you are using up there, in which case the solution could be lubricating your threads (or so I hear). Whatever it is, I'd say hang on until an actual expert can tell you more. I'd imagine you don't want that to be happening.... And the solution could be any number of things I don't know enough to explain.
I just wanted to say.... It's Easter... Wait until you've got the right solution from some experienced mech users, given small things can cause (or be symptomatic of bigger things) big problems.
Welcome to ECF. Hope any of the above is helpful; it probably isn't. But, do wait for someone more expert to come along.
Anna
I'm not too concerned about the black dots. I'm far more concerned that you're demanding (at least) 30 A from any 18650, much less one with a CDR of 23 A. This is not safe. Please take some time to learn about Ohm's law and battery characteristics before you use that mod again. You can start by poking around Mooch's site here:
Index | E-Cigarette Forum
You can check out the mech forums here for some beginner guides and to ask any questions you have.
I'm not clear about one thing. When you say your coils are 0.14 ohm, is that the resistance of the coils together (so they're 0.28 ohm each), or is each coil 0.14 ohm (for a total resistance of 0.07 ohm)?
Index | E-Cigarette Forum
You can check out the mech forums here for some beginner guides and to ask any questions you have.
I'm not clear about one thing. When you say your coils are 0.14 ohm, is that the resistance of the coils together (so they're 0.28 ohm each), or is each coil 0.14 ohm (for a total resistance of 0.07 ohm)?
Looks like Arcing to me.
I'm not Familiar with your Mod. What is it? A Single Battery Mech Mod?
And if it is a Single Battery Mech Mod, how many Amps are you asking your Battery to Provided with a 0.14 Ohms Build?
And what is your Battery's CDR Rating?
Those black spots are from the initial contact point when firing. It's near impossible to make a truly flat contact so a small part of one of those switch legs will contact the battery first, sending a high current (with a minuscule arc) through that small spot for a fraction of a second. This will oxidize that first contact point on the battery, leaving a black mark.
Other parts of your mod with contact surfaces, like eg threads, can also collect some black goop over time and need regular cleaning (oxidation raises resistance and makes your mech hit less hard). How quickly that happens depends on how well machined they are.
Your batteries are not made to sustain that build in a safe way, you should either get higher rated ones or adjust your build (unless those are 30A ones you put a green sleeve on).
Other parts of your mod with contact surfaces, like eg threads, can also collect some black goop over time and need regular cleaning (oxidation raises resistance and makes your mech hit less hard). How quickly that happens depends on how well machined they are.
Your batteries are not made to sustain that build in a safe way, you should either get higher rated ones or adjust your build (unless those are 30A ones you put a green sleeve on).
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Ok, that's a lot better than the alternative, but it's still big problem.
Ohm's Law:
I (current) = V (voltage) / r (resistance)
The voltage of a fully charged 18650 is 4.2, so with your coil:
I = 4.2 V / 0.14 ohms
I = 30 A
Mooch has found Sony's VTC 4 to have a CDR of 23 A, so the max you can safely draw from it is 23 A. You're drawing 30 A. This is not a safe setup.
While you can get 18650s with a CDR of 30 A, it's very important to leave yourself a safety margin. Some people like to have a 50% safety margin, so they wouldn't go over 15 A with a 30 A battery. Even if you're not that cautious, I can't see any reason to use more than 80% of your CDR - 24 A with a 30 A battery, or 18.4 A with your 23 A batteries. Actually, I'd consider your batteries damaged due to the excessive demand they've already experienced and I wouldn't use them anymore.
Using the 80% safety margin, your minimum resistance with a VTC 4 should be 0.23 ohms.
Please look into the topic a bit more before you continue using a mech. BTW, you've actually got a pretty good battery so I expect you've done some research, but you still need to respect its limits.
It's a single battery mech mod. With 0.14 ohms it's discharging at about 30 amps.
Then you either Need to use a Battery with a Higher CDR or you Need to build at a Higher Ohms.
Is this the Battery you are asking to provide 30 Continuous Amps?
Sony VTC4 2000mAh 18650 Retest Results...a great 23A 2100mAh battery
BTW - How Old are your Batteries?
We tend to rely on Mooch's ratings more than wrap ratings around here (for good reason - wrap ratings are often exaggerated). I see that the wrap rating is 30 A, so I can see why you thought it would work (and I apologize for implying that you didn't check that out). At the same time, the VTC 4 isn't a true 30 A and it's important to leave a safety margin, so it's still crucial to increase your resistance and find a battery with a true CDR of 30. Mooch's 18650 ratings table can help you there:
18650 Battery Ratings -- Picking a Safe Battery to Vape With | E-Cigarette Forum
18650 Battery Ratings -- Picking a Safe Battery to Vape With | E-Cigarette Forum
The black dots are from arcing due to the high current (amps). Clean them up and use an anti-oxidant or di-electric grease to lessen the problem in the future.
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BTW - How many Amps would you be Drawing if your 0.14 Ohm reading was off by just 0.02 Ohms?
And was Actually 0.12 and Not .014 Ohms.
Thanks to all of you for your replies, I'll build at higher ohms and I'll see if this problem consists.
You will always have arcing with a mech.
It's from that tiniest space before the battery makes it's connection with the contact.
Mostly it appears on the positive end of the battery.
A pencil eraser helps to remove it from a flat surface, if it's on the positive nipple you can drag it flat across a piece of white paper and "write'' it off.
Always build within the means of your battery - be safe, don't need you to make the evening news !
And the simple math to that question:
4.2v Fresh Battery Charge/0.14ohms=30amps
You have to no leeway or safety buffer if you have a short of any sort, you are already maxed and above what the VTC4 is rated for by at least 2 amps, them batteries are being cooked to death literally, one "UhOh" moment and best case scenario is you have a leaking hissing battery, worst case is a literal "KABOOM" right in your face. Minimum, absolute minimum resistance in Ohms on a single battery mech mod suggested is 0.25ohms, even with an LG HB6 true 30amp CDR battery, even with a Sony VTC5A 25amp CDR battery. Vaping is not intended to be a contest of who can blow the biggest cloud at the risk of safety, most powerful tool in a vaper's arsenal is the space above your shoulders and between your ears, think before you do something and always retest your math several times before hitting that switch. I'd much rather error on the side of caution than spend $1500 USD if not more for that hospital visit to treat 3rd degree chemical and fire burns if you are lucky and just a get a roman candle when one of those batteries go critical.
As far as the arcing spots on your negative terminals, upping your resistance should deter them, but not entirely, as @classwife posted above, once that switch contact gets close, electrical arcing happens, electrons will jump once the contact is close enough when dealing with mechs, especially the lower you go in Ohms. Need super low Ohm builds to satisfy your vape tastes, get a parallel dual battery mod, single battery mech, again iterating, 0.25ohms lowest.
With a mech, you need to clean your contacts regularly on both the mod and the battery. If the mod contacts are copper, soak them in vinegar and they should clean up like new. If you see spots or varnish buildup after soaking, use some Deoxit Red (preferred) or rubbing alcohol and a cotton buffing wheel on your dremel to clean it off. Nothing abrasive though so you don't scratch them.
On your battery contacts, use the Deoxit Red or alcohol and scrub them with a Q tip. The Dremel wheel isn't advised on the battery because it can tear the wraps.
Moving forward, a minor weekly cleaning will keep you squared away. An application of Deoxit gold (brush it on the contacts and leave it) is even better.
Building higher is good advice, but you'll still need to keep the contacts cleaned up for optimal performance. It comes with the mechanical mod territory.
On your battery contacts, use the Deoxit Red or alcohol and scrub them with a Q tip. The Dremel wheel isn't advised on the battery because it can tear the wraps.
Moving forward, a minor weekly cleaning will keep you squared away. An application of Deoxit gold (brush it on the contacts and leave it) is even better.
Building higher is good advice, but you'll still need to keep the contacts cleaned up for optimal performance. It comes with the mechanical mod territory.
Welcome and glad you joined.
Not sure how to alleviate your problem, the pattern looks like it is shaped by the push mech. spring. Might want to follow other suggestions too.
Might like to read:
DIY copper spring: FastTech Forums
Could see
ush MechanismSpring
Vaping 101: Mechanical Mods
He's using a hybrid-top single battery mech mod.
@AGoleanu , I sincerely hope you are aware of the additional precautions you must observe with a hybrid-top, direct battery mod. If not, I highly suggest that you read the section of this blog concerning faux-hybrid, direct battery mods. This is CRITICALLY IMPORTANT! The safety of your hands and face depend upon this.
- Covers the differences between a mechanical vs. regulated mod, essential safety accessories, optional safety accessories to add layers of safety to your mech, routine maintanance, use of proper batteries, proper ventilation, low resistance vaping, and faux hybrid mods.
Explain it to the Dumb Noob: Ohm's Law Calculations
- As simple as it is to use, some people have a tough time grasping the concept. Recently revised to be even more simple. Warning: Includes graphic photos of mod explosions.
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