Onboard chargers

The powerful and compact MultiCharger

Modern vehicles rely on many features that draw power from the battery. An onboard battery charger maintains performance and ensures that your vehicle will start.

453115 MultiCharger 1204R Flex NAM

The power to start your engine

Cold weather, comfort functions, and a standard driving pattern will deplete your battery faster than the alternator can recharge it. When the battery becomes discharged, it might not be able to start your vehicle. The DEFA Flex onboard smart battery charger maintains the ideal state of charge also in the extreme weather conditions. A charged battery makes the car easier to start, even on cold days, and extends battery life.

WarmUp Bluetooth kit

Improved battery lifetime

A continually low charging level or repeated discharges will damage your battery. If this happens, replacing it is often the only alternative. Discarding batteries is expensive and harms the environment. A MultiCharger onboard charger maintains the health and performance of your battery and extends it’s expected lifetime. WarmUp assemblies include a MultiCharger 1203X.

DEFA app Bluetooth

Control your system on your phone

The DEFA app gives you full control over your WarmUp system and lets you monitor your battery status. The app will visually notify you if the cable is not connected when you try to turn on the system and alert you if the cable is still attached when you start the vehicle.

Mechanic working on car


  • Modern switch-mode technology preserves your battery performance.
  • Temperature-compensated charging charges your battery in all weather conditions.
  • Automatic switch to full-power mode (quick charge) if load causes the battery voltage to fall below 13v during charging.
  • Short-circuit and reverse-polarity protection.
  • 120V recognition prevents the relay from discharging the battery when the charger is not in use.
  • Will not damage the vehicle’s electronic systems.
  • Prevents battery degradation (sulfating) and extends the lifetime of the battery.
  • A fully charged battery reduces fuel consumption and harmful emissions.

The MultiCharger 1203X onboard battery charger can be used to charge all 12V lead/acid batteries, including AGM and GEL.