Battery Amp Limit Calculator

Calculate how many Amps your Battery Should Handle

Battery Amp Calculator
mAh Rating: mAh
C Rating (Continuous Discharge): C
Battery Should Handle: Amps

Calculate how many Amps & Watts your Device is drawing from your battery.

Amp & Watt Calculator
Resistance: Ohms
Voltage: Volts
Device is Drawing: Amps
Watts

Calculate how many Amps & Volts your Device is drawing from your battery.

Amp & Volt Calculator
Resistance: Ohms
Power: Watts
Device is Drawing: Amps
Volts

Grimm Green inspired me to make these tools available, all in one place, for everyone's safety when using things like rebuildable atomizers on unprotected mechanical mods.

Power rating for rechargeable batteries

The critical factor for ecig APV use is the C rating (discharge current) in amps. The minimum possible value for safe and effective ecig use is 1 amp (= 1000mA) although ideally it needs to be higher. The ideal rating is 2.5 amps (2000mA) or better as a conventional atomizer usually draws 1A to 2.5A .

Battery amp Limits

These ratings are general guidelines taken from information on the internet and NOT all from the manufacturers.

Battery name and mah Continuous Discharge Amps Maximum Discharge Amps C Rating Safe Ohm to run
AOSIBO        
Aosibo 18350 800 mah 6.4 amp 8 amp   1 ohm
Aosibo 18650 1600 mah 20 amp 30 amp   0.2 ohm
Aosibo 18650 2100 mah 20 amp 30 amp   0.2 ohm
Aosibo 18650 2500 mah 22 amp 35 amp   0.2 ohm
Aosibo 26650 3500 mah 20 amp 30 amp   0.2 ohm
         
AW IMR
AW 14500 600 mah 4.8 amp 6 amp 8c 0.9 ohm
AW 16340 550 mah 4.4 amps 5.5 amp 8c 1 ohm
AW 18350  700 mah 6.4 amp 7 amp 8c 0.7 ohm
AW 18490  1100 mah 8.8 amp 11 amp 8c 0.5 ohm
AW 18650 1600 mah 16 amp 24 amp 15c 0.3 ohm
AW 18650 2000 mah 7.5 amp 10 amp 5c 0.5 ohm
AWT        
Awt 18350 800 mah 6.4 amp 10.5 amp   1 ohm
Awt 18500 1200 mah 8.8 amp 18 amp   0.8 ohm
Awt 18650 2000 mah 20 amp 30 amp   0.2 ohm
Awt 18650 2500 mah 22 amp 35 amp   0.15 ohm
Awt 26650 4200 mah 22 amp 75 amp   0.15 ohm
         
Efest IMR
Efest 10440 350 mah 1.4 amp 3 amp 8c 3 ohm
Efest 14500 700 mah 5.6 amp 7 amp 8c 0.8 ohm
Efest 16340 700 mah 5.6 amp 7 amp 8c 0.8 ohm
Efest 18350 800 mah 6.4 amp 8 amp 8c 0.7 ohm
Efest 18490 1100 mah 8.8 amp 11 amp 8c 0.5 ohm
Efest 18650 1600 mah 20 amp 30 amp 18.75c 0.3 ohm
Efest 18650 2000 mah 15 amp 20 amp 8c 0.4 ohm
Efest 18650 2250 mah 18 amp 20 amp 8c 0.5 ohm
Efest 26500 3000 mah 20 amp 30 amp 6.5c 0.5 ohm
Efest 26650 3000 mah 20 amp 30 amp 6.5c 0.5 ohm
Efest Purple 18350 700 mah 8 amp 10.5 amp   0.8 ohm
Efest Purple 18500 1000 mah 10 amp 15 amp   0.6 ohm
Efest Purple 18650 2100 mah 20 amp 30 amp   0.3 ohm
Efest Purple 18650 2500 mah 20 amp 35 amp   0.1 ohm
Efest Purple 18650 2000 mah 15 amp 20 amp   0.4 ohm
Efest Purple 26650 3500 mah 20 amp 32 amp   0.09 ohm
Efest Green 26650 4200 mah 15 amp 25 amp   0.5 ohm
         
EH IMR
EH 14500 600 mah 4.8 amp 6 amp 8c 0.9 ohm
EH 15270 400 mah 3.2 amp 4 amp 8c 1.4 ohm
EH 18350 800 mah 6.4 amp 8 amp 8c 0.7 ohm
EH 18500 1100 mah 8.8 amp 11 amp 8c 0.5 ohm
EH 18650 2000 mah 16 amp 20 amp 8c 0.4 ohm
EH 18650 NP 1600 mah 20 amp 30 amp 18.75 c 0.3 ohm
Imren        
Imren 18350 button top 800 mah 6.4 amp 8 amp   1 ohm
Imren 18350 800 mah 6.4 amp 8 amp   1 ohm
Imren 18500 button top 1100 mah 8.8 amp 10 amp   0.8 ohm
Imren 18500 1100 mah 8.8 amp 10 amp   0.8 ohm
Imren 18650 1600 mah 20 amp 40 amp   0.2 ohm
Imren 18650 2000 mah 10 amp 20 amp   0.2 ohm
Imren 18650 2100 mah 15 amp 30 amp   0.2 ohm
Imren 18650 2250 mah 10 amp 20 amp   0.2 ohm
Imren 18650 2500 mah 20 amp 30 amp   0.2 ohm
Imren 18650 2600 mah 22 amp 35 amp   0.2 ohm
Imren 18650 2800 mah 20 amp 35 amp   0.2 ohm
Imren 18650 2900 mah 10 amp 20 amp   0.2 ohm
Imren 18650 3200 mah 5 amp 10 amp   0.8 ohm
Imren 26650 3600 mah 20 amp 30 amp   0.2 ohm
Imren 26650 4200mah 15 amp 25 amp   0.2 ohm
         
LG        
LG 18650HE2 2500 mah 20 amp 35 amp   0.2 ohm
LG 18650HE4 2500 mah 20 amp 35 amp   0.2 ohm
         
MNKE IMR
MNKE 18650 20 amp 30 amp 18.75c 0.3 ohm
MNKE 26650 20 amp 30 amp (60 amp pulse) 18.75c 0.3 ohm
MXJO        
Mxjo 18350 button top 700 mah 6.4 amp 10.5 amp   0.8 ohm
Mxjo 18350 700mah 6.4 amp 10.5 amp   0.8 ohm
Mxjo 18500 button top 1100 mah 8.8 amp 10 amp   0.8 ohm
Mxjo 18500 1100 mah 8.8 amp 10 amp   0.8 ohm
Mxjo 18500 button top 1000 mah 8.8 amp 15 amp   0.6 ohm
Mxjo 18500 1000 mah 8.8 amp 15 amp   0.6 ohm
Mxjo 18650 1600 mah 20 amp 30 amp   0.2 ohm
Mxjo 18650 button top 2000 mah 10 amp 20 amp   0.6 ohm
Mxjo 18650 2000 mah 10 amp 20 amp   0.6 ohm
Mxjo 18650 2500 mah 22 amp 35 amp   0.2 ohm
Mxjo 18650 3000 mah 15 amp 20 amp   0.4 ohm
Mxjo 26650 3500 mah 20 amp 30 amp   0.2 ohm
Mxjo 26650 4200 mah 15 amp 25 amp   0.2 ohm
         
Orbtronic
sx22 18650 22 amp 29 amp 11 c 0.3 ohm
         
Panasonic
NCR18650B 18650 3 amp 4 amp 1.1c 1.5 ohm
NCR18650PF 18650 5 amp 10 amp 3.4c 0.9 ohm
NCR18650PD 18650 5 amp 10 amp 3.4 c 0.9 ohm
NCR18650 18650 2.7 amps 5.5 amps .5 c 1.6 ohm
any other protected 18650 3 amp 4 amp 1.5ohm
any unprotected 18650 5 amp 10 amp 0.9 ohm
Samsung ICR INR
Samsung ICR18650-22P 2200 mah 5 amp 10 amp 4.5c 0.9 ohm
Samsung ICR18650- 30A 3000 mah 2.4 amp 5.9 amp 1c 1.5 ohm
Samsung INR18650-20R 2000 mah 7.5 amp 15 amp 7c 0.6 ohm
Samsung INR18650-25R 20 amp 35 amp 0.2 ohm
         
Sony
Sony US18650v3 2150 mah 5 amp 10 amp 4.5c 0.9 ohm
Sony US18650VTC3 1600 mah 15 amp 30 amp 18.75c 0.3 ohm
Sony US18650VTC4 2100 mah 15 amp 30 amp 14c 0.3 ohm
Sony US18650VTC5 2600 mah 15 amp 30 amp 11.5c 0.3 ohm
Sony US26650VT 2600 mah 15 amp 50 amp 0.1 ohm
         
Trustfire IMR
Trustfire 14500 700 mah 2 amp 4 amp 2c 2.2 ohm
Trustfire 16340 700 mah 2 amp 4 amp 2c 2.2 ohm
Trustfire 18350 800 mah 4 amp 6.4 amp 5c 1.1 ohm
Trustfire 18500 1300 mah 6.5 amp 8.5 amp 5c 0.7 ohm
Trustfire 18650 1500 mah 7.5 amp 10 amp 5c 0.6 ohm

Chart of C ratings vs size

These ratings are general guidelines taken from information on the internet and NOT all from the manufacturers.

1C or less for some Li-FePo4
Assume 1C for generic Li-ion unless otherwise noted
1.5C for ultra/sure/trust/-fire Li-ion
2C for AW ICR (Li-ion)
3C for BDL 10440 IMR (Li-Mn)
5C for BDL 14500 IMR (Li-Mn)
8C for AW 14500 and 16340 IMR (Li-Mn)
10C for AW 18650 IMR (1600mAh) (Li-Mn)
10C for AW Li-FePo4

Max drain rate in amps is C in mAh / 1000 x C rating

Example: an AW IMR Li-Mn 14500 battery has a capacity of 600mAh. The C rating is 8C (it can supply a load of 8 times the capacity).
Therefore the max discharge current in amps is: 600 x 8 over 1000 (600 multiplied by 8 divided by 1000)
= 4800 / 1000
= 4.8 amps

This shows it has enough beef to safely and effectively run an atomizer - which some 14500's don't. In other words it is less likely to go into thermal runaway if there is an internal fault in the battery, is overcharged, and is then used to power a device that draws a relatively high current such as an atomizer; and it will not suffer from excessive voltage drop when powering the atty.

Useful formulas

Amp draw = voltage / resistance

Example: a 5 volt APV is used with a 2.5 ohm atomizer - what current is drawn?
5 / 2.5 = 2
The battery must supply 2 amps.

Power used by atomizer in Watts = volts x amps, or volts x volts / resistance

Example: a 5 volt APV delivers 2 amps to the 2.5 ohm atty - what power is used?
5 x 2 = 10
The atty uses 10 watts
or
5 x 5 / 2.5 = 10 watts

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