The CH100 has a built-in diode that only allows battery current to flow out of the battery to the 12 V and G terminals. But, because both loads are hooked up to the same battery, the system still drains the same. If there are two loads, and one is of a lesser priority than the other, the lower priority load can be controlled by connecting it to the SW12 on the data logger and turning it off if the battery voltage starts to get too low.