The battery charge level before charging is irrelevant, because each battery slot is monitored separately, so that the batteries are charged independently of each other.For the uncomplicated and quick reading of the charging status of your batteries, a colored LED display is integrated above each slot.Easy operationThe device recognizes your inserted batteries completely automatically and without tedious adjustment via buttons or switches. The charging process starts immediately after you have inserted the cell with the correct polarity. The device automatically detects defective cells and gives you a hint to sort them out.Repair modeThe Powerline 4 Smart allows you to reactivate deeply discharged cells. The charger detects the condition of the batteries and automatically starts a repair mode, whose special, gentle pulse charging technology refreshes the batteries and tries to bring them back to their old performance level.Gentle chargingThe charger has a high-quality charging technology built in, which protects the battery from rapid wear in several ways. This includes, among other things, the automatic shutdown of the charging process as soon as the cells are fully charged, as well as the gentle trickle charge for all cells after the actual charging process.