The Cyrix battery combiner is an enhanced relay controlled by a microprocessor. It automatically connects batteries installed in parallel when one battery reaches the preset voltage (indicating that the battery is being charged) and disconnects them when the voltage drops below the float voltage (indicating that one or more batteries are discharging). The Cyrix battery combiners are excellent replacements for diode isolators. Their main feature is that they exhibit almost zero voltage loss, so the output voltage of alternators or battery chargers does not need to be increased.