Switching to regulated mod; Battery questions

[IllusionCrisis]

Hello all! I just bought a Sigelei 150w for what seems to be a great price ($63.99 after shipping). Anyway, I've been using mech mods for the past year now, and I finally broke down and bought a regulated mod.

I've been using Sony VTC3's, VTC5's, and purple Efest 35A(20A). Since I've been using 1x 18650 tube mods, I need to get at least 2 new batteries (planning on 4), because I know that you MUST use 2 of the same model batteries at the same point in cycle life aka "married batteries" to prevent... well, you know.

So, my inquiries. Am I correct in understanding that the continuous discharge rating limit no longer applies to the coil, but the wattage output of the device? For instance, I could have a .2Ω build in my RDA, and according to Ohm's Law, I'd need at least 21 amperes of continuous discharge to safely run that on a mech mod with a freshly charged 4.2v battery. But in a regulated mod, if I ran that .2Ω build in my Sigelei, and fired it at, say, 50 watts, I wouldn't need nearly as high continuous discharge rate? I'm all about vaping safely (as far as batteries and power are concerned), so I'm just trying to make sure.

On to my main question... Since I must get new batteries, would I benefit more from a higher mAh rating than a higher continuous discharge rating? I like having versatility, and I'd certainly want to try my new mod at or near max power at least ONCE, to say I did haha. I am planning on getting either Sony VTC4's, Samsung-25R's, and/or LG HE4's. If I could get some suggestions, I'd thoroughly appreciate it! Or, if someone could point me in the right direction, that'd be great, too! This forum is kind of difficult to navigate for me... (took me a few minutes to figure out where the battery sub-forum was, as I thought it was a main forum).

TL;DR: Got a regulated mod, need new batteries and some more information about regulated mods in general. Which batteries are best for versatility between high amp rating and battery life?

EDIT: Oh yeah! If I could get some suggestions to online stores where I could get authentic batteries without worry, I'd really appreciate it! I know of a few, but it'd never hurt to find more.

 

[DaveSignal]

Use whatever batteries recommended by Sigelei, which might be 30A CDR, but could be anything 20A+. The mod has built-in limits for unsafe currents, but it will pull up to 30A from the batteries at 150 watts. So if you really want only a battery rated for 30A, you would be looking at the VTC series. Otherwise, a pair of 25R, HE4, HE2, or similar will work fine.
You will need to be building with coil resistances in the the range of 0.167 to 0.375 in order to get 150 watts out of the mod.

 

[Spirometry]

You are correct in the assumption in that the continuous discharge rating limit no longer applies to the coil.

When making your calculations, you need to add in for efficiency of the chip (I like to use 90% because its a nice round number and give a touch of overhead). Also unlike a mech mod the amp draw will be the greatest when the battery charge is the lowest, so you need to know the low voltage cutoff of the mod.
I don't have a Sigelei but quick research shows it has 2 cells in series with a 6.4v cutoff. So at 50w you are asking 55 watts from the battery (the battery is 2 cells in series).

Setting it at 50 watts - 55w / 6.4volts = 8.6 amps
Setting it a 150 watts - 165w / 6.4 v = 25.8 amps

For batteries try illumn.com try are a trusted seller.

 

[IllusionCrisis]

You are correct in the assumption in that the continuous discharge rating limit no longer applies to the coil.

When making your calculations, you need to add in for efficiency of the chip (I like to use 90% because its a nice round number and give a touch of overhead). Also unlike a mech mod the amp draw will be the greatest when the battery charge is the lowest, so you need to know the low voltage cutoff of the mod.
I don't have a Sigelei but quick research shows it has 2 cells in series with a 6.4v cutoff. So at 50w you are asking 55 watts from the battery (the battery is 2 cells in series).

Setting it at 50 watts - 55w / 6.4volts = 8.6 amps
Setting it a 150 watts - 165w / 6.4 v = 25.8 amps

For batteries try illumn.com try are a trusted seller.

Thanks for the info! Now, when you say to add in the efficiency of the chip, do you mean the chip causes more power to come out? Or less? At 90% efficiency, 150w output would be 135w since 150*.9=135. It seems you added 10% on to the calculations, which would be 110% efficiency.

And thanks for telling me about illumn, I was actually just looking on their site before I posted this!

 

[folkphys]

If you assume that when you set your box to output 150W, it will actually output those 150W, you'd want to know how many watts pulled from your batteries it would take to do that. We know it will need more power on the input side, because the the chip needs some of it, which means your atomizer (output side) can't have it all. So,

(Watts In) x (Chip Efficiency) = Watts Out

x(90%) = 150w
x = 150w/(0.9)
x = 166.67w

which means you could be pulling 26.04 Amps from your batteries when they get low (6.4v)......and perhaps even more when you account for their instantaneous voltage sag........because 6.4v is actually only their "standing" voltage and not voltage under load, which would be considerably lower, assuming the Sig would even allow itself to fire at that point......it could be that the Sig stops firing when it sees the sag voltage drop to 6.4v, at which point your batteries could have a standing voltage of somewhere close to 7.0v......but I digress.

 

[DaveSignal]

Either way you look at it, the amp draw at 150 watt is higher than the CDR of a 20A rated battery.

 

[IllusionCrisis]

If you assume that when you set your box to output 150W, it will actually output those 150W, you'd want to know how many watts pulled from your batteries it would take to do that. We know it will need more power on the input side, because the the chip needs some of it, which means your atomizer (output side) can't have it all. So,

(Watts In) x (Chip Efficiency) = Watts Out

x(90%) = 150w
x = 150w/(0.9)
x = 166.67w

which means you could be pulling 26.04 Amps from your batteries when they get low (6.4v)......and perhaps even more when you account for their instantaneous voltage sag........because 6.4v is actually only their "standing" voltage and not voltage under load, which would be considerably lower, assuming the Sig would even allow itself to fire at that point......it could be that the Sig stops firing when it sees the sag voltage drop to 6.4v, at which point your batteries could have a standing voltage of somewhere close to 7.0v......but I digress.

Ah, I think I understand a bit more. I'm still a bit puzzled by "chip efficiency." I know it's a fallacy to assume anything ever runs at 100% efficiency, but at 90% efficiency, wouldn't that decrease the amount of power it regulates? My apologies, but I haven't used higher math in a long time haha. EDIT: Never mind, I just got it xD!!

In any case, I bought a pair of Samsung-25r's and a pair of Sony VTC4's. Since VTC4's are 30A, I shouldn't have problems for when I feel like going to higher wattages (which won't be too often, honestly). And the 25r's should be good for just about anything else. Thanks for the help and replies!

 

[MasteroftheVape]

Samsung 25r will fire the box every bit as hard as vtc at full wattage on a regulated mod. The 25r is actually rated higher for burst discharge than even the vtc5 (100 amp burst discharge rating) per samsung tech sheets. And let's face it, 99.9999% of vaping falls under this.

Vtc series is better suited to mech users because of its efficiency and reduced voltage drop during high amp discharge.

On regulated mods the power input is decided by the chip, not the battery so voltage drop doesn't really matter. If the chip wants 100 watts, it will pull more amps to account for voltage drop and get its 100watts.

 

[edyle]

When using a mechanical mod, you tend to use 4 volts as the voltage of the battery in your calculations.

When using a regulated mod, you need to use 3 volts in your calculations.


With a 150 watt mod, you would be comfortable with batteries that supply 75 watts each, at 3 volts.
watts = volts x amps
75 = 3 x 25
So you want a battery that supplies 25 amps.