The 12v3amp LiFePO4 Charger works with all MarCum LiFePO4 Batteries, Kits, and “L” labeled systems. This charger is multi-stage for fast initial charging, reduced-charge near full, and a maintain charge cycle to prevent overcharging. A full charge of the LP41210 will take 4 – 10 hours, depending on the battery. This charger is NOT compatible with Lead-acid, Lithium-Ion Mite, or Lithium Shuttle batteries.