The Battery Tender Junior is much more than a trickle charger. It has a brain. It’s lightweight, compact, and fully automatic; very easy to use, especially in small spaces. It will keep your battery fully charged so that it is ready to go when you are! Complete 4-step charging program (Initialization, Bulk Charge, Absorption Mode, Float Mode). Automatically switches to float / maintenance voltage after fully charging the battery. If the battery voltage drops too far under load, full charger output power resumes. Solid state two color LED indicates stage of charger.