Minimum Amps

[FreddieC]

I use a mod that runs on a single 18650. The rta build runs at about 35-40 watts, so I wanted to know what is the minimum amperage in an 18650 needed for the set-up?

 

[Rossum]

15A minimum.

 

[Hawise]

Agreed, 15 amps.

The formula to find out is:

Your maximum wattage ÷ (your mod's low-voltage cutoff * your mod's efficiency) = amps needed

It can be difficult to find out the exact figures for a given mod, so we often use numbers that are on the low end of average: 3.2 v for the cutoff and 0.9 for the efficiency. You'll notice that 3.2 * 0.9 is 2.88, or very close to 3, so we often just use 3 for a rough estimate:

Amps used = your max wattage ÷ 3
= 40 ÷ 3
= 13.3 A

I don't know of any batteries with CDRs between 10 A and 15 A, so that means you'll need at least a 15A battery.

I don't know how much you know about the reliability of battery manufacturers, vendors and battery-wrap ratings, but I strongly recommend picking a battery from this chart and buying it from one of the vendors in the blue cell of the chart. This blog explains why, and, as always, we'll be happy to answer any questions you have.

 

[DaveP]

Mooch's video should give you some info for your decision. Higher MAH yields longer vape time, but you do need to stick with cells that can supply CDR (continuous discharge rate) at 15A or better.

 

[Baditude]

WATTAGE PER SINGLE BATTERY on REGULATED MOD:


Up to 45W:

Samsung 18650 30Q, 3000 mah 15 amp CDR

Sony 18650VTC6 3000mAh 15 amp CDR

Up to 60W:

LG 18650HG2 3000mah 20 amp CDR

LG 18650HE4 2500 mah 20 amp CDR

Samsung 18650-25R, 2500 mah 20 amp CDR

Sanyo UR18650NSX, 2500 mah 20 amp CDR

Sony 18650VTC5, 2600 mah 20 amp CDR

Sony 18650VTC4, 2100 mah 23 amp CDR

Up to 75W:

LG 18650 HD4 2100 mah 25 amp CDR

LG 18650 HD2 2000 mah 25 amp CDR

Samsung 18650-24S, 2500 mah 25 amp CDR

Sony 18650VTC5A, 2500 mah 25 amp CDR

Molicel 18650-P26A, 2600 mah 25 amp CDR

Up to 90W:

LG18650HB6 1500mah 30 amp CDR

LG18650HB2 1500mAh 30 amp CDR

LG18650HB4 1500mAh 30 amp CDR

Samsung 18650-20S 2000mah 30 amp CDR

​

 

[Robin Becker]

I would even estimate the efficiency with a factor of 0.8 (20% lost). That is usually the efficiency of those so-called Powerbanks for mobile phones who do similar things (Step-up to +/- 5V). Even if we assume that the efficiency on mods is a bit better due to better quality, still at high-current usually the efficiency is lower.
I would even suggest to talk about 0.75, when we talk about Chines low-cost manufacturer of mods...but it is my opinion.