BOS LE300 Smart Battery System, the batteries that will change boating are here

BOS LE300 Smart Battery System, the new frontier in energy storage.

The debate is always raging about which is the best solution between lithium batteries and traditional lead batteries. On the one hand, the almost total discharge capacity (and therefore usability) of lithium batteries, and on the other, the peak performance and power offered by traditional AGMs, which, however, cannot drop below 80% of their voltage otherwise they are irreparably compromised.

It’s quite a dilemma to face, especially when it comes to marine use, where our beloved service batteries are subjected to intensive use and must (given their cost) last a long time and not leave us stranded.

Fortunately, the German company BOS AG has come up with an ingenious solution that maximizes the strengths of the two alternatives by making them work together – an innovation that we were so intrigued by that we wanted to try it out…

About the BOS LE300 Smart Battery System

The BOS LE300 Smart Battery System is an advanced energy storage system consisting of individual 12v lithium smart battery modules, each offering 28 Ah of capacity and 12.5 A of current.

The batteries are very compact in size and are designed for parallel assembly to achieve the desired capacity, which will be determined according to the needs of the individual boat.

These lithium batteries can be used either to increase the total capacity of existing lead-acid battery packs, or to study and optimize the operation of a new battery pack, when replacing it or installing it for the first time.

But the real innovation of the BOS LE300s is that their intelligence is designed to prioritize discharging and recharging of their modules, which, by reading the voltage of the lead-acid batteries to which they are connected, effectively eliminate any deteriorating factors.

In fact, it is common knowledge that traditional batteries operate in a range between 12.8 and 10.8 V, although it is advisable not to take them to a voltage lower than 12.3 V in order not to compromise their life.

Well, the primary function of the BOS LE300 is to replace the discharge of lead-acid batteries, keeping them constantly at the highest possible voltage, using the ability of lithium batteries to deliver amps without decreasing their voltage.

In short, the BOS LE300 can discharge completely while the lead-acid batteries remain charged and healthy! Added to this is the fact that this technology is designed to be truly plug-and-play, i.e. the installation of the BOS LE300s does not require any additional charger: you only need to put them in parallel with your existing batteries, which clearly justifies the title of this article.

BOS LE300 Smart Battery System: installation

The annual check of our Daydreamer‘s batteries is an important task. Our lab-boat sails a lot and, above all, spends an average of 30/40 nights at anchor per season. Our configuration has six 110 Ah lead-acid batteries, one for the engine and five dedicated to the utilities which, as well as supporting all the on-board equipment, must also drive the hydraulic system that powers our large winches, the mainsail furler and the furler.

All this, despite the 150 watts of solar panels we have and due to the large number of nights spent at anchor, rapidly deteriorates the traditional batteries we have. In fact, after only four years of use, we find that one of the batteries is compromised and two others are below the minimum voltage level, which means they are also on their way to expiring. We have to change them all.

So we decide to trust the product we are going to test and to study a new configuration that foresees the restoration of the engine battery with a specific AGM for starting of 100Ah and, instead of the 5 service batteries, we will install only 4 AGM of 110 Ah.

In place of the fifth battery, we will instead install 4 BOS LE300 modules which, as well as optimizing the operation of our energy reserve, will provide us with a total of 102.4 Ah and will be able to deliver 50 A of current, the AGMs will therefore only be “stressed” once this reserve has been used up.

Installation is very easy, the modules are lightweight and space-saving, nothing compared to the huge effort just put into disembarking and embarking traditional batteries.

It’s really easy to fit them in, and to connect them up we simply put them in parallel with our 4 AGMs.

In our case we have chosen to pair the modules two by two so that they can be easily distributed in the space available but, if you wish, it is also possible to compose them in a single one-piece block.

The actual installation time, excluding the AGMs of course, is about ten minutes with a very low degree of difficulty. In short, anybody can do it: simply insert the modules into the available space, loosen the nuts on the AGM battery poles, insert the BOS LE300 cable lugs into the corresponding bolts and tighten again. A piece of cake.