Although the vast majority of battery experts caution to never stack batteries, a select few mods allegedly have been designed to stack batteries. Should you decide to do so yourself, educate yourself on the proper procedure to do so.
Stacked or unstacked?
In some mods, you can fit two 18350's when the mod is configured for an 18650. This boosts the voltage output from 3.6V to 7.2V which means more vapor. Yay. BUT, you should still never do this. Unless you are familiar with matching batteries, you are only endangering yourself and others. A single large battery will always be safer than stacking two smaller batteries together.
You may think, "Well, shucks, laptops have multiple batteries in them, why can't my e-cig?" Laptop batteries are specifically designed for stacking and are paired for use at the factory. When using un-matched batteries, they will discharge and provide current at different rates. This means one battery will continuously take more of the stress than the other.
You may not notice any trouble at the start, but as the batteries age with use the problem will become more severe. Push the batteries a bit further and now you've entered the realm of thermal runaway. Downside being that one battery entering thermal runaway will push the other battery into thermal runaway. Now you have two small, flaming explosives only inches from your face.
The Vamo has built-in protective circuitry within its processor, one would hope that the Vamo would shut itself down should issues arise. That being said, proper safe battery procedure must be practiced at all times.
People who choose to stack batteries must choose a pair of brand new batteries of the same type and model, and mate them for life. Once paired up they must remain together forever. The idea is for them to remain equal partners for their entire life. Do not mix a new and older battery; do not mix battery models.
Alternate the order that the batteries are put into the mod with each use. Putting the same battery in first will cause unequal draining of the batteries, and one will soon become weaker than the other. Marking the batteries as "1-A" and "1-B" is suggested to keep track of the order they are used.
Use a voltmeter or digital multimeter to measure the batteries' voltage coming out of the mod (never less than 3.2v) and coming off the charger (never more than 4.2v).
Use protection circuits. Regulated mods have built-in protection. Mechanical mods do not have protection; a Vape Safe Fuse is recommended.
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