Lead-acid batteries are filled with sulfuric acid followed by lead oxide and lead sulfate is formed. This is necessary so that current can flow. The resulting lead sulfate is initially amorphous, so finely divided and has no ordered structures. Only at rest at a lower charge it crystallizes and joins together in ever larger crystal networks that no longer can be set off and withdraw the current chemical origin. Exactly this crystallization is to prevent the device! It cut off the battery power slightly, returns it intermittently, thus preventing hibernation and thus a transition from amorphous to crystalline sulfate. Obviously he succeeds even with my two RV batteries, the starter battery for the truck and the gel battery for the living structure.
The meantime increasingly occurring cheap batteries have an equal lead surface with less lead mass and corrode much earlier. This corrosion can not stop the device, since it chemically expires completely different. Also already thick sulphate crystal composites, the device can no longer, or only slightly, reduce retroactively. With good battery (always buy from similar batteries the most severe) it works m. E. properly. It is also important as the vehicle is moved. Long rest periods and only short distances, the charge the battery slightly, prevent a viable operation, as the device for low battery is forcibly turned off to prevent a total discharge of the battery.