OptiMate 5 Start/Stop,12V 4A Automatic Battery charger & maintainer for Start/Stop, Hybrid Vehicles, AGM and Deep-Cycle Batteries (TM-221)A true "connect and forget" power charger & maintainer for your car, pick-up truck, hybrid vehicle or electrical car with ECO friendly Start/Stop Control.Ideal for all 12V engine start (SLI) batteries, including standard, flooded with filler caps and sealed EFB and AGM types.Charging is fully automatic. The automatic 6-step program saves a deep discharged battery from as low as 4 Volts and will then charge and maintain the battery, all automatically with long-term maintenance mode that keeps the battery at its optimal level 24-7.Tests battery state of health and warns if the battery loses charge. Due to poor health of battery/age. Or a high drain in the vehicle indicating other issues.Safe to charge in vehicle with provided O-11 fused battery harness or O-04 battery clips. No risk of overcharging. Totally safe for vehicle electronics. Sparks suppressed. Safe for long-term battery maintenance. Automatic shut-down if short-circuited or battery disconnected.