@zian – As your batteries drain, they output less voltage. In order to meet your power demand in watts, to compensate for the voltage more current is requested from your batteries. Having non married batteries that are at different levels of voltage means your device is drawing more current from one battery over the other – in simple terms, one battery will be working a lot harder than the other.
It is important you purchase the same battery in pairs (for a dual cell device) at the same time and charge and discharge them together. This is referred to as “married” cells. The same concept applies to triple or quad battery devices.
You can divorce a married pair of batteries, for use in single cell mods, but you should not remarry them.
HOHM Life do not make their own cells. They take cells from other manufactures and apply their own wrap to them, and in most cases exaggerte the ratings. This is referred to as a rewrap cell. Rewraps are not necessarily dangerous if you know what the limitations of the cell are. The problem is, without sophisticated test equipment and needed skillsets, we do not know what the limitations of the cells are. Fortunately for us Vapers we have
@Mooch who performs tests on these cells. Refer to the links below.
List of Battery Tests | E-Cigarette Forum
18650 Battery Ratings Table | E-Cigarette Forum