CTEK M300 Marine Charger

M300 is the charger we recommend for boats with both start and service batteries. Accompanying M300 is the maintenance charger M300starter which solely takes care of the start battery. The 25A-charger can then give maximum charging to the service batteries. The charger has a four metre long secondary cable and a temperature sensor for optimised charging irrespective of temperature, which gives extra flexibility in permanent installations. M300 is a fully automatic 8-step charger that supplies 25A and is ideal for batteries between 40-500Ah.

M300 analyses whether the battery can accept and retain the charge, it removes harmful lead sulphate crystals, gives an effective charge and automatically switches to safe maintenance charging when the battery is fully charged.

The practical Recond mode reconditions the battery following deep discharge cycles, which can occur after a long day at sea. If you intend to stay overnight onboard you can switch to Night mode for silent charging.

IP44 classification means M300 is approved for outdoor use. It does not generate any harmful galvanic currents, is fully protected from producing voltages that can damage the vehicle's electronics and has been developed to offer safe charging: non-sparking, reverse polarity protection and short circuit proof. M300 comes with a five year guarantee.

CTEK M300 Specification

Input voltage AC 220-240VAC, 50-60Hz
Output voltage Nominal: 12V
Efficiency 85%
Charging voltage 14.4V, Temperature compensated
Charging current 25A max
Back current drain* <2Ah per month
Ripple** <4%
Ambient temperature -20°C to +50°C, output power is reduced automatically at higher temperatures.
Cooling Fan
Type of charger Eight step, fully automatic, switch mode with pulse maintenance.
Type of batteries All types of 12V lead-acid batteries (Wet, MF, AGM, Calcium/Calcium and GEL).
Battery capacity 50-500Ah
Dimensions (L x W x H) 235x130x65mm
Insulation IP 44 (Outdoor use)***
Weight 1.4kg

Cable length:
◦Mains to charger - 1.8mtr
◦Charger to battery - 4.0mtr
*) Back current drain is what drains the battery if the charger is connected without the power cord connected.

**) Ripple denotes the amount of interference there is to the current and voltage. A high current ripple heats the battery and shortens its life. A linear charger has a current ripple of 70 - 400% which is much larger than the maximum 5% for a modern sealed battery. Voltage ripple could harm other equipment, which is connected to the battery.

The M300 delivers voltage and current with very low ripple. The battery gains a long service life and there is no risk of damage to other electronic devices connected to the battery.

***) IP 44 cannot be guaranteed unless the charger is positioned with its top or long side facing up.

For the technical data of the M300 starter, please see the XS 800.