Safe Battery for sub ohm coils

[BreeZe098]

Hi, It's my first post. I will be appreciated if someone answered my question.

I've been vaping sub ohm tank for 6 months. I'm trying to start building sub ohm coils. I was researching about the safety and found out that I have to use safe battery but I don't know anything about it.

Can someone tell me what kind of battery do I have to use (amp) and why does it have to be that kind of battery?


Thank you.

 

[Baditude]

These blogs will explain & answer your questions:

Battery Basics for Mods: IMR or protected ICR?

Deeper Understanding of Mod Batteries

Explain It To The Noob: Ohm's Law Calculations

Information Resources for Your First RBA

Ohm's Law for Vapers
​

This isn't rocket science, but you do need to have a basic understanding of Ohm's Law and use the appropriate batteries to sub-ohm safely. Basically, the heating coil will pull a predetermined amount of current (found with an Ohm's Law calculator) from the battery. You must not exceed the amp limit (CDR or continuous discharge rate) of the battery or very bad things may happen. Best case scenario (regulated mod) is the mod will refuse to fire the coil if exceeding the amp limit; worse case scenario (mechanical mod) is the battery will go into thermal runaway, vent gas, and possibly explode.

• If you use sub-ohm resistance coils (0.2 - 0.8 ohms) on a mech mod or high wattage regulated mod, your first priority must be for a high amp IMR battery of 20 - 30 amps CDR (maximum continuous discharge rate). Coils under the resistance of 1.0 ohm require more amp power due to their higher amp draw. Use the appropriate battery with an adequate amp rating depending upon the current draw of your coil build (*see the chart immediately below for coil amp draw vs amp rating).

* Coil amp draw from Ohm's Law calculations for Mechanical Mods:

1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw ---> requires a battery of at least 10 amps CDR
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw ---> requires a battery of at least 20 amps CDR
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw ---> requires a battery of at least 30 amps CDR
0.1 ohms = 42.0 amp draw ---> there are no batteries made to fire this resistance safely
0.0 ohms = dead short = battery goes into thermal runaway​

• If using a high wattage regulated mod, use a 20 - 30 amp CDR IMR battery, which ever your mod's manufacturer recommends. The processor's amp limit determines the amp requirement in this application, not the atomizer resistance:

If you're going to vape at 75W or higher, I recommend the Sony VTC4 2100mah 30 amp.

From 40W - 75W = Samsung 25R 2500mah 20 amp, green wrap if you can, blue wrap is just fine (same cell).

Under 40W = LG HG2 3000mah 20Amp or Samsung 30Q 3000mah 15A , almost identical in performance.

(Above recommendations are by Mooch)
​

Everyone is free to set their own 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 a 10 amp battery, that 50% would be 5 amps continuous -- a 5.2 amp draw from a 0.8 ohm coil).

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.

You may be placing a lot of faith in a cheap ohm reader in making a precise and accurate reading to a tenth or hundredth of an ohm. The most accurate and recently calibrated digital multimeters can cost over $1000.

A loose post screw holding your coil on your RBA can drastically lower your coil resistance by as much as 0.5 ohms (from personal experience).

At the time of this writing (July 2015), there are no mod batteries that can deliver more than 30 amp CDR. Any advertisement of over 30 amps is either marketing hype or a pulse discharge rating (a spec we choose not to use).

 

[Mooch]

When you've absorbed Baditude's great blogs, and are more comfortable with what battery amp rating you might need, you could also try these two:

18650 Safety Grades -- Picking a Safe Battery to Vape With | E-Cigarette Forum

There are no 18650 batteries with a genuine rating over 30A! | E-Cigarette Forum

 

[BreeZe098]

Thank you so much!
I really appreciate for your help!

Is there a difference between the wattage too?

 

[classwife]

Moved to New Members from Simple Solutions

Simple Solutions is to assist the Beginning Vaper with getting started

 

[Mooch]

Thank you so much!
I really appreciate for your help!

Is there a difference between the wattage too?

Not sure I understand your question, but...
Any battery can be used at different wattages. Some of those wattages might be safe for that particular battery and some will be too high. The wattage is calculated by multiplying the battery voltage by the battery current, i.e., Watts = Volts x Amps. So if you are running your mod at a high wattage, you will be drawing a lot of current from the battery...no matter what battery you use.

Did that help at all?

 

[Trypno]

Baditude and Mooch provided excellent answers, and if I may simplify things even more...

Sony VTC4 batteries are rated at 30amps cdr and highly recommended amongst sub-ohmers. I use VTC4s and vape down to .16ohms with no problems; though you don't want to chain vape (with a mech) at those levels because things heat up quick.

The new VTC5s are supposedly only rated at 20amps, but are being marketed as 30 so be careful.
MNKE and IMREN 26650s are rated for 60amp pulse, 40amp continuous, but truthfully, I don't think they actually go above 30; not that I'd know the difference, I'm not sure how to test amperage ratings of batts.

Also, AW IMRs are great batteries, but not for super-sub-ohming as they only push 20amps, just keep that in mind.

 

[Cullin Kin]

I'm not sure how to test amperage ratings of batts.

Just read the battery tests in Mooch's signature. He's doing the testing for us.

 

[BreeZe098]

Thank you for many answers!


Baditude recommended me a different battery depending on the wattage so I thought there will be a difference between the wattage too.

 

[sqonker]

Hi, It's my first post. I will be appreciated if someone answered my question.

I've been vaping sub ohm tank for 6 months. I'm trying to start building sub ohm coils. I was researching about the safety and found out that I have to use safe battery but I don't know anything about it.

Can someone tell me what kind of battery do I have to use (amp) and why does it have to be that kind of battery?


Thank you.

I just recently got the sony vct5 battery and I like it so far.

 

[Baditude]

Thank you for many answers!


Baditude recommended me a different battery depending on the wattage so I thought there will be a difference between the wattage too.

The Sony VTC4 2100mah 30 amp battery is a great all purpose battery and is probably the most popular and most widely recommended battery available. However, their availability/supply is sometimes scarce, and there have been issues of fakes (rewrapped cells made to look like genuine Sony's). Buy from reputable vendors such as RTD Vapor, Illumn, or Orbtronics.