What is an 'average' voltage drop?

[LeoRex]

I've recently fell in love with my humble little Nimbus clone... .7 ohm dual micros on my K100... And I am fiddling around, trying to balance the resistance to get the best vape for the longest time... and I'm now finally circling around the concept that many experienced mech users are familiar with; the voltage drop.

To those that don't know what that is.... basically, just because your battery says its 4.2 volts doesn't mean that is what is getting sent to your juice. The mod (in my case, a K100), the materials used in the connections, the posts, everything contributes to an overall loss of voltage by the time that gets to your coil (and your juice). When I throw a MM on the positive and one of the negative posts on my rda, It reads about 3.75v... which works out to about a .45v drop, under load.

Is that normal for a somewhat cheapo set of gear (simple K100, AW 18650 IMR and a FT Nimbus clone)? What are the drops that many of you see (if know)?

 

[Thrasher]

thats kinda high BUT the voltage drop will vary with the resistance of the coil as well so there is no real way to compare VD unless everyone uses the exact same battery with the exact same charge and the exact same coil.


one person will say its .18 another will say .4 on the same mod, never realizing theres a 1 ohm difference in the coil they use. you can try things like sanding posts and contacts, better springs, and thread grease but in the end you usually compensate for drop by just dropping a little more on resistance. if you dont really see a problem with it I would ignore it.

this is also the reason so many mech users are such maintenance nuts. making sure contacts and threads stay as clean as possible as any oxidation or dirt will also raise VD

 

[Rader2146]

Which AW: 1600 or 2000?

My 3 mechs play out like this:

CCTS (sanded contacts) - .32V
Sig #8 (many modifications) - .17V
Brass M16 Clone (zero mods) - .15V

All measured at 1.0Ω with Samsung INR18650-20R.

 

[Rader2146]

as resistance of the coil decreases the internal resistance of the mods base metals will increase. because the current actual flows over the metal not through it at higher current. This is known as the skin effect and is the exact reason heavy gauge wire is actually many strands of small wire.

Skin effect only applies to alternating current and is affected by frequency and cross section area. In a DC circuit 100% of the conductor is "in use"

 

[Mike.S]

If you're simply measuring the voltage at the posts which the coil is connected to, you're not measuring the voltage drop. When there's a draw, the voltage at the battery itself will drop, due to its internal resistance. You need to measure both the battery voltage (at the battery terminals), and the voltage at the coil to determine the drop.

 

[Rader2146]

That's why voltage drop is so subjective. It is extremely difficult to get a simultaneous comparative measurement. But, knowing the battery used and resistance of the coil is good enough to make a comparative judgement.

 

[Thrasher]

Skin effect only applies to alternating current and is affected by frequency and cross section area. In a DC circuit 100% of the conductor is "in use

Yea your right not enough coffee before thinking about it

 

[LeoRex]

Yeah... it is a dual coil build... dual 10 wrap 28g micro coils... meters out at 0.7 ohms. It is in a V5 RDA (nimbus clone) on a K100 mech. The batteries used is are 2000 mah AW IMR 18650 and 2250 Efest IMR 18650s. This is, by no means, a high end set up.

This all stemmed from me trying to get the right resistance for my build... balancing resistance to get the longest, best vape. I found myself switching batteries and those batteries were around like 3.8/3.7v. Now, if I dropped a little on the coils... pull a wrap on both.. I might gain a bit of vape time (and deal with the slightly hotter at the top end) before my internal vape clock tells me to change the battery.

I was just wondering about other peoples drops.