The German BOS, with its LE300 Smart Battery System, brings on board medium-small boats a hybrid system that makes the most of the characteristics of lead-acid and lithium batteries
With all the new equipment “coming on board” and the ever-increasing level of comfort, energy boats are never “satiated”.
The LE300 Smart Battery System from the German company BOS makes it possible to expand the overall energy storage capacity and rationalise its use without having to modify the classic 12V electrical system; it is a plug-and-play hybrid system that combines lead and lithium technologies, exploiting the best of both.
Details of operation
At the heart of the system are its LE300 Lithium-Iron-Phosphate (LiFePO4) smart batteries of 12V, nominal 28 Ah, and effective 25 Ah and 300 Wh.
They are compact and lightweight (229x175x76 mm for 3.4 kg), modular and can be stacked, side-by-side and installed in several blocks according to the space available on board. Once connected in parallel with the lead-acid battery (AGM, GEL, or wet cell), the system is ready to work. Up to 24 LE300 modules can be connected in parallel and only in rare cases there is a need to change or modify parameters on the charge controller.
A management software is Integrated into the LE300 that optimises the storage capacity and charge and discharge cycles of the entire system, exploiting the full potential of the batteries. Discharge priority is given to the BOS lithium modules that control the voltage of the lead-acid batteries and keep them at maximum voltage. The latter are used as an accumulator and backup, and come into operation in the event of energy peaks (at the end of the peak, the LE300s pour energy back into the lead-acid batteries, returning their voltage to 13V. This avoids numerous charge-discharge cycles to the lead ones).
The charging process
During the charging process, the lead-acid battery reaches a constant voltage charge and the charge current reduces. The smart battery system detects this and the LE300 absorbs the available energy that is not taken by the lead acid battery.
As a result, both batteries are charged at the maximum available charge current, until they are full. Especially with solar power, the full potential of the sun can be realised in every moment, while the lead acid battery gets many charging hours to reach 100% every day.
With the inbuilt heat elements, the system also has great benefits in extremely cold environments. The integrated cell heating has time to heat the lithium cells while the lead can receive high current even in freezing cold. This allows to charge the system without negative impact on cycle life.
For added safety, the BOS system is redundant: each module of the LE300 has its own built-in Smart Battery System, in case one module fails, the others continue to work without any problems.
The batteries are designed and tested to work even under extreme conditions and are protected against overcurrent, overvoltage, short circuits, deep discharge and reverse polarity.