There are many mobile and static applications where both an inverter (converting battery power to mains) and a battery charger are required. A common use is on yachts where the inverter is used to create mains power while the vessel is at sea and then the battery charger replenishes the batteries when it returns to its pontoon berth, reconnecting to a shore suppply. Similarly, there are many special vehicle applications where "mains on the move" is needed, but the primary opportunity to recharge is when the vehice returns to its storage location. In both cases, the vehicle or boats alternator will assist with supplementing the batteries while the engine is running.
When an inverter and charger are both required it makes sense to choose a "combi" unit, where both products are designed into the same enclosure. This cuts down weight, the space required and the complexity of the installation.
When separate products are used, an external means of transferring AC power between supply sources is also needed. For example, when a boat is reconnected to its shore power supply with the inverter operational, you would otherwise run the risk of the two sources of AC meeting each other in the same ring main! This would lead to damage of the inverter, the grid supply and possibly also the vessel itself! With a combi unit, an internal AC transfer relay is used, negating the need to wire this seperately.
Merlin supplies inverter / chargers - from Victron Energy.
Victron Multi
The Victron Multi is a long established and popular product with an excellent reliability record. There are a range of units from 800vA to 5kVA available complete with fully automatic, programmable and adaptive battery chargers (see smart battery chargers). The transfer time between grid and inverter is also extremely quick, allowing the units to be used as a UPS where computer or communications equipment must be kept running during the transfer from grid power to inverter and vice versa.
You can also set the maximum current available from the grid or generator and the Multi will automatically reduce the power it consumes for its battery charger to attempt the keep the boat or vehicles overall power consumption to within those limits - avoiding tripping the incoming power supply.
Unique to the Multi is a "power assist" function where the inverter can be used to temporarily supply power to cope with peak power demands on-board. This is a valuable benefit, allowing generators to be down sized to nearer the continuous power usage on-board with the inverter handling the excess. A common application is utilising "power assist" for the start up demand of air conditioning or heating systems, rather than buying a generator that is sized for that purpose, but far too large and expensive for the majority of its workload.
Various off the shelf remote control panels are available. Merlin also manufactures control panels to manage the transfer of power between three or four AC supply sources in more complex systems.
| The following documents are available for you to download |
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Easy Plus |
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Phoenix Multi |
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Quattro |
