4-in-1 Versatile Battery Doctor — Why spend $200+ to buy multiple tools that still wear out fast? FOXWELL, trusted by professionals for over 17 years, builds tools that last — The FOXWELL BC521 combines a charger, tester, maintainer, and desulfator in one durable, smart device, keeping your space tidy. It charges, diagnoses, and repairs 12V lead-acid batteries (AGM, GEL, EFB, Flooded), so your car, motorcycle, RV, or boat still starts reliably after weeks of sitting or in cold weather. Not for lithium, 6V, or 24V batteries.
Smart 8-Stage Charging for Longer Battery Life — Unlike standard battery chargers that blindly push power, this smart car battery charger uses an intelligent 8-stage charging process — including Desulfation, Soft Start, Float, and Pulse Repair — to automatically adjust based on your battery's condition. Select from 5A / 3A / 1A modes to match different battery types, while built-in temperature compensation ensures safe, unattended charging overnight or during long-term storage.
Accurate Battery Testing Before Charging — Don’t guess battery condition anymore! More than a 12v battery charger, BC521 can be a true car battery tester to check your battery’s real condition with 99.9% accuracy, including voltage, SOH, SOC, internal resistance, cranking performance, and alternator status. The clear LCD display shows whether your battery needs charging, repair, or replacement — helping you avoid wasted time and unexpected breakdowns.
Bring Sleeping Batteries Back to Life — Don’t replace your battery too soon. This smart battery maintainer uses Maintainer Mode to save batteries you thought were dead, recovering deeply discharged and sulfated batteries that have sat unused for weeks or months — restoring lost capacity and extending battery life. Once fully charged, this trickle charger automatically switches to Unattended Mode, maintaining optimal voltage to keep your battery fully charged at all times without the need to unplug — perfect for seasonal vehicles and long-term storage.
Built‑In Safety & Outdoor Durability — This automotive battery charger protects both you and your battery from risks during unattended charging, such as sparks, overcharging, and overheating, with 6 built‑in safety features: over‑voltage, over‑current, overheating, reverse polarity, overcharge, and over-discharge. Additionally, its IP65 waterproofing and flame‑retardant housing ensure safe use both indoors and outdoors, while temperature compensation keeps your battery healthy in extreme conditions.
Easy for Anyone to Use — Designed for everyday drivers, not just professionals. The clear LCD and LED indicators show charging status and battery health at a glance without guessing. One-touch FN button as a quick way to test/charging without searching through the menu, saving time on repeated tasks. Review past charging and test history to track battery performance over time. Plus, it's clear instructions will make setup fast and frustration-free.