Battery Support On the Go: The D250SE is a fully automatic, 5 step charger that supplies up to 20A of power to any 12V lead-acid or lithium* service battery from 40–300Ah. It has selectable charge algorithms for AGM and 12V lithium batteries (*12V LiFePO4). Achieve Nominal Power from Your Solar Output: Solar Panel Regulator with Maximum Power Point Tracking (MPPT) optimizes available power. Charge Service and Starter Batteries: When the service battery is fully charged, the D250SE will automatically redirect maintenance charge power to the starter battery. Smart Alternator Compatible: Full functionality with all types of alternators. Built-In Temperature Sensor: Allows you to achieve maximum charge levels no matter what the temperature. Safe and Easy to Use: Splash and dustproof, designed to protect vehicle electronics and non-sparking, reverse polarity protected, and short-circuit proof. Clean voltage and current delivery ensures no surges or spikes. Protects Sensitive Equipment: Unlike less-sophisticated chargers, there is no need to disconnect the battery; the D250SE is specially designed to not damage electronic systems. No overcharge or undercharge ever. 2-year warranty.