These systems generally use a smaller inverter (or combi) to power the lower AC loads, when a larger AC load is required the generator is started and the combi becomes a battery charger to recharge the DC battery bank. This leads to reduced generator running hours and therefore reduced maintenance and fuel costs. Almost all good quality combis now have additional benefits when used in the hybrid system, the combi can 'power assist' the generator or the shore power during the short periods of peak AC power consumption. This allows the generator size to be kept to a sensible level rather than sizing the set to cover the peak loads. The combi's also have the capability to regulate the amount of AC power the system draws when operating as a battery charger, this ensures that shore power is not 'tripped' or the generator overloaded, again making the system more efficient. Lastly the newer, better combi's also now have integral solar MPPT regulators built within them so the solar connections can be made directly at the combi rather than another remote electronic box.
Similar system in principle to the AC generator system but using a dedicated DC battery charging generator. The system generally has a larger inverter (or combi) that is capable of powering the total AC power requirement, as above the combi draws power from the appropriately sized battery bank to supply AC power to the on board systems. The battery bank is then monitored by the generator and charged as and when required, this can all happen automatically if required. Operating like this means the generator only ever runs when the battery bank needs it and is always correctly loaded as the charge level is controlled by the engine speed, making for a very efficient system. The combi has all the benefits mentioned above in both systems.
The primary objective of a 'Hybrid System' is to create an efficient cost effective system. Ideally the system should be simple to operate and have a lower running cost than conventional power systems, hence the inclusion of renewable sources. A further benefit should be a reduced impact on the environment, both systems deliver this as the generator run time is reduced and the greater the input to the system from renewables the less time the generator is required to run. The generator capacity is also reduced as it can be sized to the average load rather than the peak load. Its a well known fact that traditionally generators have been oversized to cope with the peak demands of the system, this no longer applies with the hybrid system as the inverter carries the short term peak load along side the generator. It also means that the other traditional service issues of lightly loaded generators are avoided as small loads, sometimes for longer periods are supplied by the inverter not the generator.
In order to get the most efficient system we need to look at all possible power inputs to the design. If the main engine is running for long periods then we should consider fitting split charging devices with advanced regulators so the main engine alternator is utilised to charge the inverter bank as this will also reduce generator run time.
Fischer Panda are also able to support the Hybrid Power solution for larger vessels. The variable speed 'iSeries' range of Panda generators are all easily parallel connected to each other meaning that it is now possible to have several smaller generator systems rather than one very large one. Once connected in parallel the set will work with full load sharing capabilities and auto start. This is a real step forward for larger boats as it means much smaller generators running when only lighter loads are required but you still have the capability to run all sets in parallel when full power is required, whats more this can all happen automatically. Another big advantage to the larger boat is the tremendous space and weight saving of the variable speed generators.