Combi inverters – 230 V from the battery, charging on shore power
A combi inverter combines a sine-wave inverter, a charger and automatic changeover in one unit. On the move it produces 230 V for on-board appliances from the battery; on shore power or generator it supplies the loads directly and charges the battery at the same time. In this category you will find the Studer Xtender XTM and XTH with accessories, the Mastervolt Mass Combi Ultra and the pure inverters of the Cristec DCW series.
In brief: Combi inverters replace inverter, shore power charger and changeover switch with a single unit – the compact solution for boats and vehicles with a shore connection.
Studer Xtender XTM and XTH
The pure sine wave, high overload capacity and high efficiency allow reliable start-up of motor loads with high inrush current. On shore power, the on-board batteries are charged automatically via a PFC-controlled charging stage and the 230 V appliances are supplied with shore power.
- Smart-Boost: inverter power is added to mains or generator power, for example to start an air conditioner on a weak shore connection. Can also be combined with existing inverters.
- Power Sharing: the charging current is reduced automatically when the loads use up the adjustable shore power limit.
- System power: up to nine Xtenders work together in parallel and three-phase, powering loads up to 63 kW.
- Load detection: adjustable standby from very low loads.
- Multi-function contacts: two potential-free changeover contacts, programmable e.g. for generator start, load shedding or fault indication.
Accessories: RCC-02 and RCC-03 remote controls with graphic display for configuration, CAB-RJ communication cable, BTS 01 battery temperature sensor and RCM 10 remote control module.
Mastervolt Mass Combi Ultra
Mastervolt combi inverter with inverter, charger and changeover in one unit – see product page for data.
Cristec DCW series – pure inverters
Inverters for 12 V and 24 V systems, when only 230 V from the battery is needed and charging is done by a separate charger.
How the inverter works together with shore power and generator is explained on the topic page Shore power on boats.
Frequently asked questions about combi inverters
What is a combi inverter?
A combi inverter combines inverter, charger and changeover unit in one device. Without shore power it produces 230 V for on-board appliances from the battery. When the boat or vehicle is plugged into shore power or the generator is running, it switches through automatically, supplies the loads directly and charges the battery at the same time.
What do Smart-Boost and Power Sharing mean?
Smart-Boost adds inverter power to an existing source such as shore power or a generator when its power is not sufficient, for example when starting an air conditioner at a weak dock pedestal. Power Sharing, conversely, reduces the charging current as soon as the loads use up the set shore power limit. This keeps the dock fuse from tripping.
How much power is possible?
Depending on the model, a single unit covers the usual on-board loads. For more power, up to nine Studer Xtenders can be connected in parallel and three-phase to run loads up to 63 kW. The rated output of each model is on the product page; we are happy to help with sizing.
Combi inverter or pure inverter?
A pure inverter such as the Cristec DCW series only produces 230 V from the battery. A combi inverter such as the Studer XTM, XTH or Mastervolt Mass Combi Ultra also charges on shore power and switches automatically between sources. For boats and vehicles with a shore connection, the combi inverter is usually the more compact solution.
