4-in-1 Battery Charger, Tester, Maintainer & Desulfator — Why spend $200+ on multiple tools? Trusted by professionals for over 17 years, FOXWELL BC521 combines smart battery charging, testing, maintenance, and desulfation in one durable, space-saving device. Designed for all 12V lead-acid batteries (AGM, GEL, EFB, Flooded), it helps ensure reliable starts for cars, motorcycles, RVs, and boats — even after weeks of sitting or in cold weather. Not compatible with lithium, 6V, or 24V batteries.
Smart 8-Stage Charging for Convenient & Automatic Battery Care — Unlike basic chargers that blindly push power, BC521 intelligently adjusts charging through an advanced 8-stage process, automatically selecting the appropriate current (1A–5A) based on your battery’s condition to help prevent over- or under-charging. With adaptive charging modes and built-in temperature compensation, it’s safe to leave connected overnight or during long-term storage — no need to constantly check, adjust settings, or unplug.
Accurate Battery Testing Before Charging — More than a 12V battery charger, with FOXWELL technology, the BC521 works as a true battery tester, letting you check your battery’s real condition before charging, so you know whether it actually needs charging, maintenance, or replacement. Key data including voltage, State of Charge, State of Health, internal resistance, cranking performance, and alternator output are displayed on the clear LCD, helping you avoid wasting time on weak batteries and reduce the risk of unexpected breakdowns.
Revive Old Batteries & Keep Seasonal Vehicles Fully Charged — Worried about a dead battery from long-term storage? Maintainer and repair functions help reduce sulfation and slow battery aging, especially for batteries that sit unused for long periods. Once fully charged, the charger automatically enter Unattended Mode to maintains optimal voltage, keeping stored or seasonal vehicles ready to start without draining the battery.
Built-In Safety & Outdoor Durability — Designed for worry-free unattended charging, this automotive battery charger helps protect both you and your battery from common risks like sparks, overcharging, and overheating. With 6 built-in protections, an IP65 waterproof rating, and a flame-retardant housing, it’s safe to use both indoors and outdoors, even in challenging conditions.
Easy for Anyone to Use — Designed for everyday drivers, not just professionals. A clear LCD with LED indicators shows charging status and battery health at a glance, with no guessing required. A one-touch FN button simplifies charging and testing, while built-in history lets you review past results — making setup fast, simple, and frustration-free.