Free car battery charging timer. Trickle chargers need 8–24 hours; fast chargers 2–6 hours. Track your charge cycle with a clear alarm. Start instantly.
Trickle charger (1–2A): 24–48 hours for a fully discharged battery. Slow charger (4–6A): 8–12 hours. Fast charger (10–20A): 2–6 hours. Smart/maintainer charger: automatic, can be left indefinitely. Time depends on battery capacity (Ah) and depth of discharge.
A charging rate of 10% of battery capacity (Ah) is ideal. For a 60Ah battery: 6A. For a 100Ah battery: 10A. Charging above 20% capacity (fast charging) risks overheating and reduces battery lifespan. Trickle charging at 1–2A is gentlest and best for long-term health.
Yes — overcharging causes electrolyte loss (for flooded batteries), heat damage, and can cause hydrogen gas buildup. Standard chargers should be disconnected when fully charged. Smart/automatic chargers switch to maintenance mode automatically and cannot overcharge.
With a smart charger: the indicator light turns green or the charger switches to maintenance mode. Without smart charger: measure voltage with a multimeter — 12.6–12.8V is fully charged. 12.4V is 75% charged. 12.0V is 25% — a concerning level requiring immediate charging.
Not necessary for most modern chargers. Keep connected in-car unless the battery is physically damaged or very deeply discharged. If keeping in-car, ensure good ventilation. Remove battery terminals in reverse order (negative first) if charging a car with sensitive electronics.