Most of our personal vaporizers are powered by removable and rechargeable lithium-ion batteries. Here is what all the "specs" mean.
The numbers on a battery have some meaning. Let's look at the 18650 battery:
- the first two digits, 18 represent the diameter in millimeters.
- the third and fourth digit, 65, represent the length in millimeters.
- the fifth digit, 0, is a number used by manufacturers to help with calculation of the length (and is basically ignored)
note that this is for an unprotected flat top battery. If you have a protected battery, add 2.5 to 3 millimeters to the total length and 0.5 millimeters to the diameter.
You can start to see how this applies to personal vaporizers. The 11 millimeter Cig-alikes use 10 series batteries, the 14 millimeter personal vaporizers use 14000 series batteries (14500, 14650, etc.), the new 16 millimeter personal vaporizers use 16340 and 16650 batteries, the 18 millimeter advanced personal vaporizers use 18340, 18350, 18490, 18500 and 18650 batteries, and the large 26 millimeter "mods" use the 26650 batteries.
ICR vs IMR vs INR
Not all lithium-ion batteries are created the same. You will usually see something like ICR 18650 3100 mAh. There are essentially three types that for personal vaporizers: ICR, IMR and INR.
- ICR uses lithium cobalt oxide. The "I" is for Lithium Ion, the "C" is for Cobalt oxide cathode, and the "R" is for the round form factor. ICR batteries are typically lower cost and the claims for capacity appear very high but will run out of power very quickly. ICR is NOT considered a high-drain battery.
- IMR uses lithium manganese oxide. The "I" is for Lithium Ion, the "M" is for Manganese oxide, and the "R" is for the round form factor. These are the most common high-drain batteries used for vaping.
- INR uses lithium iron phosphate. The "I" is for Lithium Ion, the "N" is for Nickel/Manganese oxide cathode, and the "R" is for the round form factor. These are harder to find, slightly more expensive, but are also the safest and high-drain.
ICRs have a higher specific energy density than IMRs (higher mAh rating), but also a higher internal resistance and lower peak load current. They also suffer from a lower thermal runaway threshold than IMR at a full 4.2v charge (130–150C°C vs 170–180°C).
mAh represents the rated milli-Amp hours. With IMR batteries, this is usually fairly accurate: a 650 mAh battery will usually last 6.5 hours when used at its rated voltage.
The innovation by many manufacturers to increase the mAh and rated amps is pretty impressive. There are now 30A and 35A batteries available that are targeted specifically at mechanical mods. These can provide quite a "kick" to the vaping experience – but have no effect on advanced personal vaporizers. Devices that support variable voltage and variable wattage have an inherent limitation in that they can only draw up to a maximum of about 10.5 amps.
Series and Parallel
You can "stack" batteries to achieve different results. If you put two batteries one on top of the other, you are connecting in series. That is the positive of the bottom battery is connecting to the negative of the top battery. When you do this, you are doubling the voltage and getting the same mAh. That means that when you stack two 18350 batteries you are getting 7.4 volts. This is in "series". Connecting in parallel is when you connect the two positives with the two negatives. In parallel, you are doubling the mAh and keeping the voltage the same as one single battery. So, if you wire up two 18350 batteries so that the two negatives are connected and the two positives are connected, and both are 800 mAh, you are getting 3.7 volts with 1600 mAh.