Description
Product Overview
The Battery Tender 4 Amp Car Charger is a compact, lightweight charger designed for 12 V automotive batteries. Built with a painted exterior and solid‑state circuitry, it provides a steady 4 A charge and automatically transitions to a float mode to maintain optimal voltage without overcharging. Weighing just 2.4 lb and measuring 6.9 × 3.33 × 1.91 in, it fits easily in a glove box or garage shelf. Certified by UL, CSA and CE, the charger supports lead‑acid, AGM, gel‑cell and lithium (LiFePO4) batteries, delivering versatile performance for a wide range of vehicles.
Usage
Designed for everyday drivers, fleet managers and hobbyists, this charger excels in both home garages and professional workshops. Connect it to a car, truck, motorcycle, RV or seasonal boat battery and let the intelligent system monitor voltage levels. The two‑color LED indicator shows charging status, while the spark‑proof clamps and reverse‑polarity detection ensure safe connections. Ideal for maintaining battery health during long storage periods or for quick top‑ups before trips.

Why Choose Us
Battery Tender combines decades of battery expertise with modern safety features. The adaptive ISM charging algorithm automatically resumes full power if the battery voltage drops under load, extending battery life. Our rigorous testing guarantees spark‑proof operation and reliable performance across temperature extremes. With a 4.7‑star rating from over 2,700 customers, the charger is trusted for its durability and ease of use.
Key Features
- Automatic float mode prevents overcharging and extends battery lifespan
- Spark‑proof clamps and reverse‑polarity detection for safe connections
- Two‑color LED indicator provides clear charging status at a glance
- Compatible with lead‑acid, AGM, gel and lithium (LiFePO4) batteries
- Compact, lightweight design fits in tight storage spaces
FAQ
Can this charger be used on a 6 V battery?
Yes, the charger supports both 6 V and 12 V batteries, making it suitable for a variety of small engines and motorcycles.
How long does it take to fully charge a dead 12 V battery?
Charging time varies with battery capacity, but a typical 50 Ah battery will reach a full charge in approximately 12‑14 hours at the 4 A rate.
Is the charger safe for lithium (LiFePO4) batteries?
Absolutely. The charger’s adaptive algorithm detects battery type and adjusts the charging profile to suit lithium (LiFePO4) cells, ensuring safe and efficient charging.
What does the two‑color LED indicate?
Green means the battery is fully charged and in float mode; amber indicates active charging; red signals a connection error or reverse polarity.
Do I need to monitor the charger while it’s operating?
No. Once connected, the charger automatically manages the charging cycle and will maintain the battery without supervision, thanks to its float mode and safety features.




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