Oximiser 601 can be left permanently connected to provide guaranteed long term battery care. Quickly charges battery at up to 600mA/hour until full and maintains a gentle trickle charge to keep battery optimised. Essential Battery Optimiser Suitable for 12V automotive battery types up to 30Ah including: Gel, AGM and maintenence free Recovers deeply discharged batteries Protected against short circuits 2 year guarantee 3 Stage battery management system: Polarity Check: checks the battery leads have been connected correctly Bulk Fast Charge: charges at a fast rate to bring the battery to approximately 85% capacity Float Charge: applies a small float charge current to maintain voltage.