The BD-2 battery desulfator from Solar Converters rejuvenates weak and dead batteries. It uses sharp spikes of current forced into the battery to "jar" sulfate crystals and cause mechanical and electrical resonance to grind them down, removing sulfation from battery plates. It can be used for 12, 24 and 48 volt batteries. Voltage and pulse strength is adjustable. Two wires connect to positive and negative battery terminals.
Solar Converter BD-2 Battery Desulfator 
The BD-2 battery desulfator from Solar Converters rejuvenates weak and dead batteries. It uses sharp spikes of current forced into the battery to "jar" sulfate crystals and cause mechanical and electrical resonance to grind them down, removing sulfation from battery plates. It can be used for 12, 24 and 48 volt batteries. Voltage and pulse strength is adjustable. Two wires connect to positive and negative battery terminals.