From Forgotten Catamaran to Solar-Powered Electric Cruiser

An Australian restoration project combining electric propulsion, 61.4kWh of lithium storage and 8.68 kW of bifacial solar power for extended cruising throughout Southeast Asia

A boat that had been waiting for another adventure

Some boats spend their entire lives tied to a marina.

This one had already sailed around the world.

In his early 20s, an Australian sailor set off on an adventure that took him across oceans and around the world aboard a 32-foot sailing catamaran. After years of cruising, the vessel eventually found its way to Langkawi Island, Malaysia, where it was placed into storage.

Then life happened.

For more than a decade, the catamaran remained there, waiting patiently for its next chapter.

Eventually, the owner decided it was time to bring her back to life, but this wasn’t going to be a simple refit.

The restoration began virtually from scratch, with the vessel stripped back to its bare hulls and rebuilt around a very different concept:

Electric propulsion, extensive solar generation and enough battery storage to allow serious cruising without relying on fossil fuels.

The intended cruising grounds were the islands and coastlines of Southeast Asia, particularly Indonesia. For a sailor undertaking extended and often solo blue-water voyages, the brief was ambitious.

The vessel needed to be lightweight, reliable, highly efficient and, above all, redundant. And there was one major rule:

No compromising on the batteries.

Designing the energy system around the boat

For an electric vessel, the battery bank isn’t simply another component of the propulsion system.

It effectively becomes the heart of the vessel.

Unlike a conventional diesel-powered catamaran, where fuel provides a relatively high amount of stored energy for its weight, an electric vessel needs to carefully manage every kilogram. Battery capacity, weight distribution, solar generation, propulsion requirements and auxiliary loads all have to work together.

Lithium battery technology was therefore the obvious choice.

High energy density, low weight, excellent cycle life and the ability to deliver substantial continuous power make lithium iron phosphate (LiFePO4) particularly well suited to a vessel where both energy and weight are critical considerations.

The owner spent considerable time researching potential suppliers before approaching Deep Cycle Systems (DCS).

The decision wasn’t simply about finding someone who could supply a large lithium battery bank.

DCS was selected because of its extensive experience with marine battery systems, complex DC & AC power systems and demanding off-grid applications, combined with a broad range of 12V, 24V and 48V lithium products.

Over several months, DCS worked closely with the owner to develop the energy architecture and optimise the battery placement and overall weight distribution throughout the vessel.

The final system incorporated eight DCS 51.2 V 150Ah lightweight aluminium batteries, creating a total nominal storage capacity of: 61.4 kWh.

These batteries were selected not only for their energy density and weight characteristics, but also because they are designed for demanding applications beyond recreational boating, including industrial and golf-cart applications, featuring very capable electronics.

That level of engineering pedigree was important.

This wasn’t a weekend cruiser that would occasionally leave the marina.

The owner intended to take the boat offshore, spend extended periods away from shore power and explore some of the most remote cruising destinations in the region.

8.68 kW of solar — and a very clever roof

Once the battery capacity had been established, the next challenge was obvious:

How do you put enough solar on a 32-foot catamaran to make 61.4 kWh of battery storage genuinely useful?

The answer was to make the solar array part of the vessel itself.

A custom aluminium braced frame was CAD designed specifically for the catamaran to accommodate 14 × 620W bifacial solar panels, providing a total installed solar capacity of: 8.68kW

But the solar structure serves another important purpose.

It doubles as a substantial canopy, providing shade and shelter over the vessel, something that becomes extremely valuable when cruising tropical waters.

The elevated design also creates excellent airflow beneath the panels.

That matters because solar panels become less efficient as their operating temperature rises. Rather than mounting the panels directly into a vessel structure where heat can become trapped, the elevated canopy allows air to circulate naturally around the panels.

And because the selected panels are bifacial, solar energy can also be harvested from the rear of the panels.

That means reflected light from the water and surrounding surfaces can contribute to generation.

It’s a simple example of the philosophy behind the entire project:

Don’t just add components to the boat—make every component perform more than one job.

The canopy provides shade.

The structure supports the solar array and further braces the hulls.

The airflow helps keep the panels cooler.

And the bifacial panels provide the opportunity to harvest additional energy from reflected sunlight.

The one-day recharge challenge

The owner had a very specific objective.

If the vessel was anchored for a day, he wanted enough solar generation to potentially take the battery bank from approximately 10% state of charge back to 100%, subject of course to available sunlight and real world conditions.

With 61.4 kWh of storage, that’s a substantial amount of energy.

It also meant the solar system couldn’t simply be treated as an auxiliary charging source.

It needed to be a major part of the vessel’s energy architecture.

The 8.68kW solar array was therefore designed to do two jobs.

First, it provides the energy required to replenish the battery bank during periods at anchor.

Second, when conditions allow, it can provide enough instantaneous power to allow the vessel to cruise directly from solar generation without drawing energy from the battery bank.

That is an important distinction.

The battery bank provides energy independence and energy buffering, while the solar array can directly support propulsion during favourable conditions.

Instead of thinking of the battery as something that constantly needs to be recharged, the system is designed to minimise how often the batteries actually need to do the heavy lifting.

Seven MPPT chargers for one very good reason

Large solar arrays on boats come with their own challenges.

Masts, rigging and other equipment can cast shadows across the panels, and even partial shading can significantly affect the output of a conventional string arrangement.

Rather than connecting the entire array to one or two large solar controllers, the vessel uses seven 35A MPPT solar chargers, with each controller managing a pair of panels.

This creates a highly distributed solar architecture.

If part of the array is affected by shading from the mast or rigging, the impact is largely isolated to that section rather than dragging down the performance of the entire solar array.

It also provides another layer of redundancy.

If one MPPT charger has a problem, the remaining solar array continues operating.

For a vessel designed around extended solo cruising, that matters.

Because when you’re hundreds of nautical miles from the nearest workshop, “she’ll be right” isn’t really a system design strategy.

Electric propulsion – with multiple layers of redundancy

The primary propulsion system consists of two 10kW electric propulsion motors.

Two independent propulsion units provide manoeuvrability, efficiency and, importantly, redundancy.

The original sailing rig was retained, including the mast with an addition of a furling jib.

That means the vessel can still harness wind power when conditions are favourable.

The result is a genuine hybrid propulsion philosophy:

Solar + battery + electric propulsion + sail.

When there is sufficient sunlight, solar generation can directly support propulsion.

When additional power is required, the 61.4 kWh battery bank provides the energy reserve.

When the wind is favourable, the sail can take over part of the propulsion load.

And if the electric propulsion system ever suffers a problem, there is another backup.

An old Tohatsu two-stroke outboard has been retained and can be rapidly deployed if required.

It may not be the most glamorous piece of technology on the boat, but when you’re offshore, redundancy beats glamour every time.

A 48V heart with a 12V nervous system

While propulsion represents the largest energy demand, the vessel still contains  a wide range of conventional 12 V loads.

Refrigeration.
Lighting.
Water pumps.
Navigation equipment.
Instrumentation.
Communication systems.

Rather than maintaining a separate large 12 V lithium battery bank, these auxiliary systems are supplied directly from the main battery system through a 48V to 12V DC-DC converter.

This reduces unnecessary battery weight and simplifies the overall electrical architecture.

For conventional AC loads, a 5kW 230 V inverter provides household style electrical power when required.

The result is a compact and highly integrated energy system built around the 48V battery bank.

One battery system effectively becomes the energy source for the entire vessel.

And then the boat comes home

Perhaps one of the more interesting aspects of this project is what happens when the boat isn’t cruising. The owner has designed the vessel to effectively become a mobile power station. When the boat is hauled out and back at home, it can be connected into the property’s electrical
system. That means the enormous battery bank doesn’t simply sit idle when the boat isn’t at sea. The vessel can provide stored energy for the owner’s property and other electrical loads.

So the same batteries that power an electric catamaran through the Indonesian islands can also provide useful energy back on land.

It’s a pretty good example of getting your money’s worth out of a battery system.

Built for the journey ahead

This project is more than the restoration of an old catamaran.

It represents a fundamentally different approach to cruising.

A vessel that once sailed around the world in its owner’s youth is now being rebuilt for another generation of adventures, with a modern
electric powertrain, 61.4kWh of DCS lithium storage and 8.68kW of bifacial solar generation.

The goal isn’t simply to eliminate diesel.

It’s to create a vessel that can generate, store and intelligently use its own energy while retaining multiple independent propulsion options.

For extended cruising through the islands of Indonesia and Southeast Asia, that combination offers something incredibly valuable: energy independence.

And it demonstrates what is possible when lithium battery technology is treated as part of the vessel’s overall engineering, not simply as a replacement for a lead-acid battery.

From a 32-foot catamaran that spent more than a decade sitting in storage in Langkawi, to a solarpowered electric cruiser preparing for a new life at sea, this project has been a genuine ground-up transformation.

For DCS, it is exactly the type of application our battery systems are designed to support.

Whether you’re building an electric vessel, upgrading a marine house bank, powering an off- grid system or simply looking for batteries that are built properly rather than built cheaply, the principle remains the same: Use quality lithium technology, engineer the system properly, and don’t leave your energy supply to chance.

Real-World Performance Figures Are In

The theory is one thing.

Putting the boat in the water and seeing what the system actually does in the real world is another.

After completing his first two weeks cruising, the owner has now provided DCS with some early performance data, and we’re pretty happy with what we’re seeing.

9.1kW of solar production!

On clear, sunny days, the 8.68kW bifacial solar array is producing around 9.1 kW of continuous peak solar power, equating to approximately 170 A into the 51.2 V battery system.

Yes, that’s right – the array is actually exceeding its nominal 8.68 kW rating under favourable conditions, thanks in part to the additional energy being harvested from the rear of the bifacial panels.

More importantly, the solar system is doing exactly what it was designed to do.

10% to 100% SOC by 4pm

The owner has confirmed that on a good sunny day, the solar system is capable of taking the 61.4kWh battery bank from approximately 10% state of charge back to 100% by around 4pm.

That was one of the key design objectives of the project.

The boat can spend the day anchored, use its stored energy, and then allow the solar array to do the heavy lifting during the following daylight hours.

No diesel generator required.
No shore power required.
Just a large solar array, a well-sized lithium battery bank and a whole lot of sunshine.
Which, fortunately, Southeast Asia isn’t exactly short of.