What is considered a good voltage drop?

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Wow! I'm actually picking up a lot from you guys answers. Thank you very much guys! And oh im pretty aware with battery limit, i know my build is low but im using dual 18650 parallel box mod and yes if i was using a single battery then i would be above samsung's max amp limit, its 20A for the 25R's. Am i wrong for thinking parallel doubles the mAh and amp while series doubles the volts and amp limit and mAh is still the same?
 
+1 to @Kaezziel . Voltage drop across a resistance coil doesn't tell you much. Voltage is supposed to drop across a resistance, see Ohm's Law for a complete statement. What you're actually interested in is losses, specifically I^2R losses in the equipment; the voltage drop across the coil is work, ie. heat on the coil, and not a loss. The question mekkies are asking when they talk about voltage drop is "how much power is my mod/atty wasting, instead of using it to heat the coil," and Kaez is right: you find that out by measuring at the posts with no coil installed, and comparing this value to battery voltage. BTW, .18 is lower than I would care to build on 25Rs in a $20 parallel box. That draws 23+ amps. If you get a bad connection and are only working one battery, you are begging for a vent.

Surprisingly the box mod i got has a good connection, i used it all day and charge my batteries after they were at the same volts @ 3.69
 

suprtrkr

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No, perfectly correct. Parallel doubles amperage and holds voltage constant; series doubles voltage and holds amperage constant (and the watts stay the same either way on the same coil.) Note, if you will, when I offered my caution I specified a bad connection reducing the mod to one battery. If you were using VTC4s, instead of 25Rs, I wouldn't have said it. VTC4s will tolerate 23 amps :)
Wow! I'm actually picking up a lot from you guys answers. Thank you very much guys! And oh im pretty aware with battery limit, i know my build is low but im using dual 18650 parallel box mod and yes if i was using a single battery then i would be above samsung's max amp limit, its 20A for the 25R's. Am i wrong for thinking parallel doubles the mAh and amp while series doubles the volts and amp limit and mAh is still the same?
 
No, perfectly correct. Parallel doubles amperage and holds voltage constant; series doubles voltage and holds amperage constant (and the watts stay the same either way on the same coil.) Note, if you will, when I offered my caution I specified a bad connection reducing the mod to one battery. If you were using VTC4s, instead of 25Rs, I wouldn't have said it. VTC4s will tolerate 23 amps :)

Yes sir! You know what i'll do myself a favor and and use my 25R's on my VW from now on and my VTC4's strictly just on mech mods thank you for the advice sir
 
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suprtrkr

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Yes sir! You know what i'll do myself a favor and and use my 25R's on my VW from now on and my VTC4's strictly just on mech mods thank you for the advice sir
any time. FWIW, I never put anything in a mech but a VTC4 for exactly that reason. If you build to the battery's nominal 20A limit, it's a comforting feeling knowing you've got an "invisible" 10A safety margin built into the battery. Never know when you'll get a stuck button or a coil short or something; and safe is always better than sorry. Some batteries are better for a specific purpose than others. I use VTC4s in my mechs, but I just bought a dozen LG HG2s for my RX200s, and when I set my woman up with her little Sigelie, she got 25Rs.
 

suprtrkr

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Check it out boss see what you think of it, im just surprised how cheap the mod is and it hits really hard www.88evape.com nemesis box mod
lol, I looked it up when you first posted so I could give you the right answer. It's not my style, but it is reasonably priced and appears well constructed. Frankly, I don't see a lot of sense in multi-battery mechs unless you are a cloud competitor. Back in the day, mechs were the only way to top 15 watts, but this is no longer true. You can get more power and much better safety and battery life in a regulated mod. Don't get me wrong: I love mech mods and use them every day. But if cloud is where I want to be, I reach for my Snow Wolf or an RX200. Mechs are beautiful: the simplicity attracts me; they can exhibit much better efficiencies than a regulated (that's the I^2R losses I was talking about); and it's a challenge to build them well. My personal taste is different from yours. I lean to one battery tubes; and I'll pay extra for fine engraving and smooth magnetic switches and rhodium/copper contacts and screw adjustments rather than live springs, and so on. But love them as I do, I'm not blind to their limitations. Let's face it: you can get more cloud out of a .5 26/32 Clapton at 50 watts on a regulated than you can out of a .25 26ga slick coil at 70 watts on a mech because the surface area is greater and radiating hotter. :)
 
lol, I looked it up when you first posted so I could give you the right answer. It's not my style, but it is reasonably priced and appears well constructed. Frankly, I don't see a lot of sense in multi-battery mechs unless you are a cloud competitor. Back in the day, mechs were the only way to top 15 watts, but this is no longer true. You can get more power and much better safety and battery life in a regulated mod. Don't get me wrong: I love mech mods and use them every day. But if cloud is where I want to be, I reach for my Snow Wolf or an RX200. Mechs are beautiful: the simplicity attracts me; they can exhibit much better efficiencies than a regulated (that's the I^2R losses I was talking about); and it's a challenge to build them well. My personal taste is different from yours. I lean to one battery tubes; and I'll pay extra for fine engraving and smooth magnetic switches and rhodium/copper contacts and screw adjustments rather than live springs, and so on. But love them as I do, I'm not blind to their limitations. Let's face it: you can get more cloud out of a .5 26/32 Clapton at 50 watts on a regulated than you can out of a .25 26ga slick coil at 70 watts on a mech because the surface area is greater and radiating hotter. :)

Haha yes that is so true! I stopped using tube mods now im really loving dual battery set up and i build from .15 to .2 once in a while i do .3 on my evic mini and .4 to .6 on my noisy cricket :)
 
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Dlmdavid

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image.jpg

I hope this makes sense to you. Basically if those are the values your reading it says that your mod has an internal impedance of 0.0325 ohms. That also means that of the 90 watts your mod is using, 75 of it is being used by your coil and the other 15 is being wasted. I'm not sure what a normal voltage drop is but that says your mod is essentially 80% efficient. Also sorry I wrote down .18 but it should say .16, the math should still be correct though.
 
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I hope this makes sense to you. Basically if those are the values your reading it says that your mod has an internal impedance of 0.0325 ohms. That also means that of the 90 watts your mod is using, 75 of it is being used by your coil and the other 15 is being wasted. I'm not sure what a normal voltage drop is but that says your mod is essentially 80% efficient. Also sorry I wrote down .18 but it should say .16, the math should still be correct though.

Yes sir it does! You're not very far but yes i do get your point! Thank you :)
 

Bunnykiller

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I look at voltage drop as the same way I look at driving my car on the highway... is the wind heading towards my car ( head wind) or is it coming from behind me ( tail wind) and does that extra 4-5 mph wind really mess up my mpg while driving on the highway??? ;)
Im not going to worry about it... I need to get from point A to point B :)
 
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