BOS – How to extend any boat’s lead-acid battery system with lithium batteries

With a complete switch to lithium batteries, there’s always the need to change the system electronics. While maintaining an existing lead-acid system and adapting it with new batteries ultimately leads to throwing out old ones to match the state of charge of the new ones. It seems that no matter what is chosen, one must bite the bullet. BOS batteries  and their patented hybrid mode provide the solution.

When installing the LE300 or the BOS battery S the main problems of extending existing electrical systems can be avoided. Via true plug and play, the poles of the lithium battery are connected to the lead-acid battery, which works quickly, easily, and safely by circumventing any changes to the system electronics.

Old batteries can be kept and recharged to a sufficient state of charge since charging the lead-acid batteries is prioritised in the hybrid mode. Meanwhile, the lithium battery provides power to the loads on the boat.

Lithium for daily cycles and lead as a backup

During daily operations, it is the lithium battery that provides the power to loads on the boat, like the fridge, the air conditioner, or the lighting. In the case of significant load peaks, both batteries are accessed in parallel to cover the power needed. Since most of the power is being taken from the lithium battery, the lead-acid battery remains at a high state of charge and is thereby protected from sulphation. This is how the BOS lithium batteries can extend the lifespan of the lead battery by up to 10 years.

Lithium extension in under 60 seconds

What is attractive about the LE300 from BOS is that the entire electrical system can stay as it is; the modules are simply connected to the positive and negative poles of the lead battery (including AGM and gel). The true plug-and-play installation can quickly be done by most end-customers themselves, who then enjoy an immediate improvement for relatively little effort and investment. It is modular and easy to connect with further modules, each adding another 25.2 Ah of usable capacity.

BOS battery S

The team of BOS Balance of Storage Systems from southern Germany takes pride in manufacturing genuinely unique products. Their latest innovation – the DAME Award-nominated BOS battery S – is much more than an 80Ah battery. It is the key to numerous new applications and business models that yet are to be explored.

The new BOS battery S from BOS is a true innovation due to its exceptionally low weight, space efficiency and cold resistance. It has infinite communication options and smart software features. The solution is almost equally simple to install as the LE300 – however, system sizing should be done by professionals.

Other than with its smaller ’sister’, the hybrid mode is optional. For those who want to leave the lead battery for good, it can run as a pure lithium system on the lead charger. Or even combine with both, lead and LE300.

In hybrid mode, the BOS battery S can cater to bigger use cases like electric drives, either as a primary power supply or as support for the existing bank.

As an example, tourist boats in Amsterdam are getting too heavy due to the weight of more and more lead batteries. Whenever some of those batteries weaken, the entire bank needs to be replaced – a huge investment.

With BOS battery S, only the weak batteries must be taken out and can be replaced by the lighter lithium extension. Just as with the LE300, the BOS battery S will protect the lead bank for a longer lifespan. Big peak loads will still be drawn from the lead cells.

Moreover, the battery features a modularity that enables swappability between places and voltages. This mobile usability makes it possible to move the batteries whenever and wherever they are needed. Its electronic module is removable, and the lithium component can be taken along on a handle. It is possible to use one and the same module in a 12V hybrid setting on the boat, in a 24V installation in a vehicle, or as part of a 48V solar home system, moving back and forth. The modules can also be charged in a rack and used upon demand, like in a boat or battery rental. As a result, both the private and industrial sectors can implement and make use of the BOS battery S.