by Dom Wiseman

The new Charge Mate Pro 90 by Mastervolt is an electronic relay that allows a second battery to receive up to 90A of charge current from a single alternator. It is suitable for all battery types and ideal for recharging Lithium Ion cells. It comes with built-in safety features and is a perfect solution for high power demand on board. It works well where there is a need for power with limited charging options.

In most cases where a boat has two batteries on board, a cranking battery and a running battery for onboard services or an electric engine for instance, the second battery usually requires its own charging solution.  A mechanical relay will charge the flattest battery first, and then switch to the other. In cases where the cranking battery is not the flattest this could leave you with not enough power to start the engine.

The new Charge Mate Pro 90 works differently. It always prioritises the primary battery whilst still charging the secondary. This reduces the risk of a slat cranking battery significantly.

The Mastervolt Charge Mate Pro 90 is able to charge both a bow thruster battery and a service battery connected to the same alternator. It would prioritise the service battery for the bulk of the charge, whilst still feeding current through to the bow thruster battery. Return current is automatically blocked, even if the secondary battery is of a higher voltage, which helps to keep the bow thruster battery sufficiently charged. The current limiting prevents power dips of the onboard electrical network. In the event of a main battery failure, an emergency start facility is available by means of an optional bypass or ‘battery bridge’ switch.

Mastervolt products are built to last. Designed specifically for marine use, they are chosen by competitors in gruelling yachting events such as the Volvo Ocean Race. One of the harshest and most testing races on the planet.  The unit and electronics are rated to the demanding IP65 standard. This means it is dust tight and protected from heavy seas or powerful jets of water.

The relay is located in a corrosion-resistant enclosure flanked by two heat sinks with operation monitored via built-in LED indicators. The unit includes automatic battery detection, so it can work seamlessly with either 12 V or 24 V systems.

The Charge Mate Pro 90 adds to the existing model line-up, and offers a unit that is easy to install and meets the demand for prioritisation or current limitation.