Mastervolt Charge Mate Pro 40 split charge relay 83304002 is a current limited electronic charge relay with high efficiency and reverse current protection. The Pro40 split charger is suitable for leisure and professional marine and mobile applications. It is an effective solution for high power demand on board and for the need of prioritised charging or current-limited charging.

A secondary battery on board requires a dedicated charging solution. The Charge Mate Pro makes it possible to distribute the charger or alternator current effectively between two battery banks such as a starter and a service battery. The Mastervolt charging relay connects both batteries during charging and keeps them isolated when discharging, significantly reducing the risk of a flat starter battery.

The Charge Mate Pro offers an additional advantage over mechanical charge relays, by limiting the charge current to the second battery. Like a starter battery, the primary battery will be charged with priority. The return current is automatically blocked even when the secondary battery has a higher voltage. An emergency start function is possible by connecting an optional bypass switch to the Charge Master Pro.

A marine application example is the connection of a bow thruster battery to a service battery. The Charge Mate Pro ensures that the service battery is always charged with priority. The blocking of the return current from the bow thruster battery guarantees that the bow battery remains charged while the current limiting also prevents power dips of the onboard electrical network.

General specifications

Monitoring: LED (warnings and status indication)

Output current: limited to 40 A

Number of battery outlets: 2

Input voltage range: 9-32 V

Parallel configuration: yes

Battery voltage: automatic 12/24 V detection

Remote switch functions: on, off, auto, start assist

Dimensions, hxwxd: 157 x 140 x 80 mm (6.2 x 5.5 x 3.1 inch)

Weight: 0.88 kg (1.9 lb)

Compliance: CE

Technical specifications

Connection possibilities: 3 x fast-on connectors (switch, ground and status) • switch: for an optional single pole ON-OFF-ON switch for remote operation • status: for an optional LED indicator

Power consumption: switch open: < 1 mA at 12/24 V DC

Battery types: all types (Lithium Ion protection via Multi purpose contact, product code 77030500)

Switch on voltage: 13.5 V (12 V) / 27 V (24 V)

Switch on delay: 5 sec

Switch off voltage: 12.75 V (12 V) / 25.5 V (24 V)

Switch off delay: 2.5 sec

Relay: electronically (mosfets with low voltage drop of max 0.2 V)

Temperature range (ambient temp.): -40 °C to 60 °C (-40 °F to 140 °F)

Protection degree: IP65

Key Features

Electronic charge coupling with very low voltage drop

Effective dual charging

For all batteries, incl. Lithium Ion

Charge current secondary battery limited to 40A

High system reliability with main battery charge priority

Unidirectional - blocks return current

Prevents onboard electrical power dips

For all kinds of chargers & alternators

Monitoring with LED status indication

IP65 electronics in corrosion-resistant case with aluminium heat sinks

Fast & easy installation