ZeroJet has come of age this year with its first product, the electric jet propulsion for small boats, now in production. Their mission to revolutionise the small electric boat market with both fun and quality is progressively being realised. The product offers small boat owners a safe, yet high performing and manoeuvrable solution, thanks to a unique mix and optimisation of electric and hydrodynamic technologies. This results in a fun experience that isn’t possible with traditional propellor based electric alternatives. Its proprietary motor design is 60% smaller than other similar products, resulting in a compact design, freeing up precious space on small boats.

Applications and Integrations

A common application of ZeroJet’s product is as a propulsion system for tenders which are used for larger boats. With many yacht management and insurance companies considering banning lithium-ion batteries onboard yachts due to safety concerns, the Lithium Iron Phosphate technology implemented by ZeroJet provides a much safer solution to provide boat owners and captains peace of mind. 

A number of leading boat builders are well into their development programmes to integrate ZeroJet’s electric jet solution into their 2024 boat release programmes, and several new boat launches this year will be ZeroJet Powered™.

Prestol Composites is one such company that, over the past few months, has been diligently working to optimise their hull design specifically to accommodate the ZeroJet electric jet system. With a background in designing world-class composite structures for Olympic athletes competing in kayak, canoe, and bobsleigh events, they are transferring this expertise into the electric boat market. Now launching as SPARK Boats, this Latvian-based boatbuilder is already accepting orders for their lightweight composite tender with an integrated ZeroJet Powered™ solution (www.spark-boats.com).

To better support existing customers with their product rollouts and to help new customers with their boat design and integration projects, ZeroJet are pleased to announce the establishment of a base in Europe. Declan Price and Matt Forbes will head up the sales and support operation, based out of Southampton on the UK’s south coast. Declan will be returning to the UK after spearheading ZeroJet’s sales from New Zealand and Matt Forbes brings his extensive boat builder knowledge across the European Market to the team. Says ZeroJet CEO Mark Robotham:

“We have outgrown our ability to meet the high level of interest and support required to service the European market, so the timing is right to build our European team”.

Company background 

ZeroJet’s initial company roots came from serial entrepreneurs and co-founders Neil Mans and Bex Rempel’s success in high performance powered surfboards, resulting in a number of records including 75 km/hour electric powered vessels. Ultimately pivoting the business in 2019 to apply their technologies into the small boat arena led to the birth of the ZeroJet brand and business. 

 "Up until now, there simply weren't enough options for climate-conscious boat enthusiasts who wanted a boat that was not only environmentally friendly but fun to drive. We want to bring the buzz into electric boats rather than the traditional putt-putt solutions available previously for small boats” says ZeroJet CTO & Co-Founder Neil Mans. 

Partnerships, Funding & Awards to Date

In 2020, they raised seed capital, and with their new team of 10, successfully built an electric jet tender in partnership with Offshore Cruising Tenders. Receiving positive feedback and learning from this first-generation system, ZeroJet doubled their team size, refined their product, and began to gain international traction. 

In 2022, ZeroJet raised a Series A round, led by Venture capital company, Movac. The oversubscribed round also garnered support from Australia’s Investible Climate Tech Fund, the NZX listed Booster Innovation Fund as well as family offices, high net worth individuals and repeat investment from NZGCP, Impact Enterprise Fund and K1W1. The company was also recognised and awarded the 2023 NZ Hi-Tech Startup Company of The Year Award. 

During 2023, system performance and efficiency were enhanced with the design and development of a new jet pump and an in-house purpose-built electric motor. This Generation 2 system was showcased at METSTRADE 2023 in Amsterdam, and the partnership with Highfield Boats, the world’s leading aluminium RIB manufacturer, was recognised in the Boat Builder Supply Chain Collaboration Award category. These accolades demonstrate industry recognition of their innovative product, offering further proof of the fast growing marine electric market.  

A bright future ahead

“ZeroJet’s intellectual property with its compact electric motor and system, combined with the exciting user experience and more importantly the impressive list of boat builders who are creating great boats with our systems makes ZeroJet a company worth watching.” says CEO, Mark Robotham. 

 “We look forward to growing the business in 2024 in partnership with new and existing boat builders and investors as this exciting sector and our success takes form.”   

 For more information on ZeroJet, visit zerojet.com. 

About ZeroJet 
ZeroJet is a fast growing and exciting start-up developing high performance electric jet propulsion systems for boats. ZeroJet designs and manufactures electric jet propulsion systems for tenders, meeting the growing demand for powerful, quiet, safe, sustainable and reliable boating. The New Zealand based company was founded with the goal of eliminating the need for combustion engines on small watercraft. 

Sustainable boating is officially the way of the future, and forward-thinking boat builders are making sure to move to electric boats now to stay ahead of the competition and gain an advantage. In order to obtain a significant share however, you must choose the electric boat propulsion system that will give you the greatest competitive edge. Unfortunately, choosing which electric propulsion system to employ can be overwhelming given the amount of options available. So in this article we outline what you should look for when comparing electric boat propulsion systems so you can be sure the investment in your new electric tender or RIB range pays off.

We’ve written this article for boat builders looking to produce an electric tender or RIB around 3-5m in length and targeting customers wanting to use with their motherships for short trips to and from the shore, to explore surrounding locations, or for watersports, fishing, and swimming. Based on this size, the electric boat would be stored in a tender garage onboard the mothership, or hung on davits on the back of a cruiser boat.

The electric opportunity- why move to building electric boats?

What to look for in an electric boat propulsion system for an electric tender or RIB

Choosing an electric propulsion system for your electric tender or RIB

The electric opportunity- why move to building electric boats?

As a result of clear environmental concerns, political pressure, and compelling options, consumer demand for electric boats is booming. While it is estimated that electric boats represent just 2% of the recreational watercraft market today, the global electric boat market is projected to reach a whopping $16.6 billion by 2031. 

And thanks to the lucrative opportunity, advancements in electric propulsion technology mean that boat builders no longer need to compromise on practicality or performance in order to go electric. In particular, inboard boat propulsion technology has experienced significant innovation, so builders can now achieve higher margins by selling world-class boats as a whole package to  their customer or through their dealer network. 

Boat buyers won’t settle for any electric boat however- they have high expectations and are willing to pay a premium for the electric boat that requires the least compromise. The zero compromise boating revolution has indeed begun. 

What to look for in an electric boat propulsion system for an electric tender or RIB

Performance

Here’s what to look for in an electric propulsion system to produce a high-performing electric boat that boasts easy maneuverability, speed, fast acceleration and efficiency: 

• Direct drive systems: If your electric boat is powered with a direct drive system, it will respond faster to throttle changes, suffer fewer energy losses and have a lower center of gravity than one containing a gearbox.

• Jet propulsion: Boats powered by electric jet systems experience less drag than outboard motor boats as they do not have any parts protruding below the hull. They can be more efficient as the high jet exit velocity generates more thrust the faster they travel, unlike electric outboards which can encounter resistance at higher speeds due to their propellers and drive legs. For a detailed comparison of electric boat motors please see our guide Electric jet boat motors or electric outboard motor- which is best?

• Inboard configuration: Unlike outboard motors which have their engines mounted on the transom of an electric boat, inboard boat motors give an electric boat a more centralised weight and a lower center of gravity. This results in more on-board space and often easier handling

• Lightweight: With less mass to accelerate and maintain in motion, boats powered by lightweight electric propulsion systems will consume less power and experience a reduced moment of inertia, allowing it to accelerate quicker and reach higher speeds. The world-leading jet unit by ZeroJet for example, weighs 40 kg excluding battery packs (and does this without compromising power). 

• Right power output for your target boat size and weight: an electric boat propulsion system with insufficient power for the size of the boat may lead to difficulty reaching desired speeds and getting up onto the plane. An electric boat weighing roughly 150 kg total and carrying an average of 2 passengers will need approximately 15 kW of power (20 hp equivalent).

• Range and runtime: For the intended use outlined above, your electric boats should offer around 40-50 minutes runtime & 10 nautical miles range so customers experience less range anxiety when using your boat out on the water.

• Efficiency at both low and high speeds: This will ensure your boat offers the best mix of range at high speeds (especially helpful during time-sensitive trips) and runtime at low speeds (especially helpful in speed restricted areas or during leisurely cruising). 

Safety 

Here’s what to look for in an electric propulsion system to help you produce safe electric tenders or RIBs for your customers: 

• Low voltage system: Voltage is a key determinant of safety on an electric boat as one that is too high increases the risk of electrical shocks or burns. The most advanced electric propulsion system can be low voltage without compromising performance. For example, ZeroJet designed a world-leading 48 V system that is able to deliver a high amount of power despite its modest voltage.

• Safe batteries: LiFePO4 batteries are the superior electric boat battery as they are safer due to a very low risk of thermal runaway. They are also far less likely to ignite under extreme conditions, even if damaged or punctured.

• Sophisticated Battery Management System (BMS): Look for one that prevents excessive current draw, and monitors and maintains safe battery temperature, current and throttle input. 

Reliability

Here’s what you’ll want to look for in an electric propulsion system to deliver an electric boat your customers can rely on: 

• A minimum IP rating of IP64: The higher the IP rating, the better. The electric boat propulsion system’s IP rating is dictated by the international IP standard. This standard indicates the level of protection against water, dust, accidental contact, and intrusion and the electric boat propulsion system's overall ability to withstand the harsh marine environment.

• Protective battery cases: Look for waterproof and impact-resistant cases that protect the battery packs from the elements and accidental damage.

• Few moving parts: Less moving parts mean less components to fault:

  • Direct drive system: These don’t contain transmission components, such as gears, pulleys or chains. 

  • Electric jet boat systems: Unlike electric outboards, they do not require a drive leg, propeller, power unit or enclosed electrical components exposed to the elements on the transom. 

  • Brushless DC motors: Compared to brushed motors, they have no mechanical brushes that wear out and which can generate heat during operation. They can last tens of thousands of hours. 

Support to design and integrate

Here’s what to expect from an electric boat propulsion system supplier to ensure that you can achieve your vision and avoid compatibility issues and performance limitations:

• System options: An electric boat propulsion system should offer system placement or configuration options as well as battery pack options (in different kWh) for achieving different range and runtimes. For example, the ZeroJet Gen2 electric jet boat systems offers both 5 kWh and 10 kWh battery packs with a number of different system configurations.

• Help in determining technical feasibility: To help assess compatibility with your boat design, hull type, propulsion arrangement, and other onboard systems.

• Engineering support: Throughout your design, prototyping and testing stages, including supplying 3D files and a prototype based on your design.

• Minimal modifications needed:  A compact electric boat propulsion system with few moving parts requires less modification to hull design and internal compartments.

To discuss the systems we offer and determine the technical feasibility of the ZeroJet Gen2 system for your electric range, book a consultation with the ZeroJet team.

Easy to install

Here’s what to look for in an electric boat propulsion system to ensure the production efficiency of your new electric boat range: 

• Plug and play system: The electric boat propulsion system should start working when first connected, without reconfigurations. For example, one that has a waterproof housing containing mounting hardware and running gear in one unit.

• Technical support and training: Technical support and training for easy troubleshooting during installation and commissioning. 

After-sales service

Here’s what to look for in an electric boat propulsion supplier’s after-sales service to ensure that your customers have a positive experience:

• A minimum 2-year warranty: Based on recreational use and on both the electric system and batteries.

• Accessible after-market repairs: For both in-warranty and out-of-warranty repairs. Service agents should be available in major locations that you have customers or distribution to.

• Easily available spare parts: Easily available over the entire expected lifetime of boat ownership with access to repairs and replacements. 

Choosing an electric propulsion system for your electric tender or RIB

So as a boat builder, how do you choose a system when you want to electrify your tender or RIB range? Electric boat propulsion systems will vary in their appeal, and ultimately selecting the right system depends on your specific design and build requirements and the significance you assign to each criteria we have covered in this article.

Book a consultation with the ZeroJet team if you’d like to discuss electric system options.

Thanks to rapid advances in battery and boating technology, boat buyers no longer need to choose between sustainability and performance, making electric boats an easier choice for more people. However, similar to other electric transport options, the range of an electric boat is always a key consideration, especially if there are limited charging options for you out on the water! This article covers electric boat range anxiety and options to overcome potential range issues, so you can make the switch to electric with confidence.

What is range anxiety?

Since ‘range’ refers to the maximum distance a vehicle can travel on a single battery charge, range anxiety, as applied to boating, is the fear that your electric boat will run out of battery power before you are able to recharge it, leaving you without battery power out on the water. While there are many ways to avoid this scenario, the fear alone could make boaties feel they need to constantly check their batteries, or even stop them from moving to an electric boat in the first place. 

How Do You Overcome Range Anxiety?

First, it is important to note that running completely out of battery power on the water is a rare occurrence and unlikely to happen if the electric boat is used responsibly. Most electric boats on the market are designed for specific applications, and have range and runtimes to match these use cases. Larger boats with power on board can be used to charge electric tenders and RIBs, and marina berths have electrical connections with many installing dedicated charging infrastructure—and this is growing at pace. In fact, the number of charging locations for electric boats around the world is the reason the adoption of electric boats is expected to be faster than that of their on-land counterparts. 

While electric boat range could understandably be an area of concern, here are three recommendations to follow to help overcome any potential range anxiety:

1. Choose the Right Electric Boat 

2. Plan your Trips Well 

3. Maximise your Electric Boat’s Range and Runtime

1. Choose the Right Boat:

If you’re looking for an electric tender or RIB for short trips to transport family, friends and supplies to and from your mothership, for inner harbour fishing, swimming, or watersports, then a boat with a minimum of 10 nautical miles range and runtime longer than 1 hour is recommended. Like the range and runtime of most vehicles, the actual limits are very dependent on the weather conditions and how the vehicle is used - see below for more details on this.

An electric boat’s ability to get up onto the plane quickly, accelerate quickly, and efficiently use its power in all conditions, are key factors in determining how far an electric boat can travel on a single charge. When it comes to choosing an electric boat for use as a tender, you’ll want to look for a light-weight aerodynamic boat with as many of the below features as possible:

Power and weight balance:

To ensure your electric tender or RIB performs optimally and safely, it is essential it has the appropriate power output for its weight because insufficient power will lead to increased energy consumption. A 3-4m tender or RIB carrying 2 people on average will require around 15kW of power (20hp equivalent). If however, you intend to carry more than 4 people or heavier loads in your boat regularly, you may need to look at a different tender/RIB size and power mix.

Inboard configuration:

An electric boat with an inboard configuration (engine located inside the boat’s hull) operates more efficiently as its centralised weight and lower center of gravity reduces resistance in the water, particularly in rough conditions. This is unlike outboard-powered boats that have their engines mounted on the transom at the back of the boat.

Lithium Iron Phosphate (LiFePO4) batteries:

LiFePO4 batteries have a very high energy density, meaning more power in less weight, and therefore requiring less energy to move through the water. They are fast charging meaning less down-time, and are significantly lower maintenance, longer lasting and more resilient than other battery types. For more information on why you should choose a boat with LiFePO4 batteries, please read our article Top 5 reasons why Lithium Iron Phosphate (LiFePo4) is the best battery for your electric boat.

Informative display:

The boat’s display should allow you to track your energy consumption by showing:

• The battery charge/discharge rate so you can monitor the charging process. 

• The boat’s traveling speed so you can drive efficiently. 

• The remaining estimated range and runtime based on the current speed and battery charge level. 

Jet propulsion:

Jet systems can deliver faster acceleration with fewer energy losses compared to other types of propulsion. To learn more about this, please read our guide to Electric Boat Motors.

A portable charger:

It is important that the batteries can be charged from outside of the boat, whether from a dock or tender garage so you are not limited in charging locations. To do this, you will need a suitable charger, a cable with the appropriate plug, and a charger connection.

Efficient charging:

Ideally, the electric boat’s battery should take no longer than 4 hours to charge from 20-99% so you can have more time out on the water! 

For a detailed guide on what features to look for when choosing an electric boat, please see our buyer’s guide.

2. Plan Your Trips Well

The best way to ease any range anxiety is to be prepared with a good plan before you leave on your trip. Here are some tips to ensure you never find yourself short of charge out on the water: 

1. Remember the rule of thirds: Use a third of your charge to get to your destination, a third to get back to your mothership (or to a charging port), and always have a third in reserve. If you plan as if 30% of your battery capacity is 0% and follow that plan, you will leave plenty in reserve. 

2. Check the distances between locations (online or on your mothership’s GPS navigation). Plan this ahead of time and remember to not significantly change your route spontaneously! 

3. Remember that if you are traveling in rough conditions, traveling at inefficient speeds, and carrying a lot of supplies or people, your energy consumption will be greater than usual and therefore your range and runtimes will be less than usual. 

4. Identify potential charging locations before heading out. These locations typically include marinas and any designated charging stations. 

5. Learn how long your battery takes to charge to specific levels so you can incorporate waiting time into your plan. . 

6. Always check your battery level state of charge (SOC) before departing. 

7. Charge when stopped, don’t stop to charge- ideally do top-up charging when you are in-between trips so your state of charge is above 80% for your next trip.  Check access to charging sources as most electric boats can be charged using standard AC power, so they can be charged on the mothership in-between uses, as well as at marina berths via a 16A socket. 

And simply keeping an eye on your battery level state of charge and always erring on the side of caution means responsible boaties will have nothing to worry about.  

3. Maximise your Electric Boat’s Range and Runtime

An electric boat’s estimated range and runtime is typically stated on the manufacturer website. However, it is not always clear that these claimed times are based on standardized testing conditions only, and the ‘real world’ range and runtime will vary based on actual use.
In addition to asking for any conditions or assumptions that manufacturers have provided around their claimed range and runtime numbers, here are some other practical tips to avoid unnecessary energy consumption and maximise your electric boat’s range and runtime: 

Drive efficiently: 

• Drive at planing speed:  wherever possible, driving at planing speed allows the boat to glide over the water with reduced drag. Once the boat is on the plane, it typically becomes more energy-efficient.

• Minimise idling: avoid unnecessary idling or prolonged periods at low speeds as idling consumes energy unnecessarily. When the boat is not in use or when waiting, consider shutting off the propulsion system to conserve energy.

• Avoid excessive acceleration: avoid sudden bursts of acceleration as it consumes more energy from the battery. Gradual and smooth acceleration will be more energy-efficient to get to planing speed. 

Ask for recommendations from the electric boat supplier on the most efficient speed ranges and other energy-saving techniques tailored to your boat's design and propulsion system.

Drive to the conditions:

Check the weather forecast and try to avoid rough conditions. Choppy seas, strong headwinds, heavy rain, extreme temperatures, and strong tidal currents mean more energy is required to move the electric boat. 

Manage on-board weight:

Avoid unnecessary weight as this requires more energy to move the boat through the water. Remove unnecessary equipment, supplies, or personal belongings that are not required for the trip.

Maintain proper battery health:

Maintaining proper battery health is critical. When batteries are not properly maintained, they will degrade and deliver less range over time. It is recommended that you follow the manufacturer's guidelines for battery charging, discharging, and storage. Choosing resilient and low maintenance batteries can be key to preserving your electric boat’s range and runtime. 

With a little extra care, you can experience the benefits of going electric without compromising your time out on the water! 

For further reading, please see these related articles: 

• Electric boats for sale- a 2023 buyer's guide to going electric [with checklist]

• Electric jet boat motor or electric outboard motor- which is best?

Choosing the right electric boat battery is crucial as it is a costly and critical component that will impact your boat's performance. However, it can be an overwhelming decision since electric boats on the market employ a wide variety of rechargeable batteries. In this article we cover the different types of batteries which are available, and explain why Lithium Iron Phosphate (LiFePO4) batteries are the recommended choice for electric boats.

Types of rechargeable batteries for electric boats: 

There are three main types of rechargeable batteries which can be used in electric boats: 

Lead-acid batteries

The most common types of Lead-acid battery are Flooded lead-acid (FLA), Absorbent Glass Mat (AGM) batteries Gel batteries, and Valve-regulated lead-acid (VRLA) batteries. 

Nickel-based batteries

Nickel-cadmium (Ni-Cd) and Nickel-metal hydride (NiMH) are the most common types of Nickel-based batteries.

Lithium-ion batteries

Lithium-ion batteries are a battery technology that uses Lithium-ion as the critical element of their electrochemistry. They are the most popular rechargeable battery in the world today, used in many applications from laptops, mobile phones, EVs, and small watercraft.

There are many types of Lithium ion batteries but the most common are Lithium Nickel Manganese Cobalt Oxide (NMC), Lithium Cobalt Oxide (LCO), Lithium Manganese Oxide (LMO), Lithium Nickel Cobalt Aluminum Oxide (NCA), and Lithium Iron Phosphate (LiFePO4).

48 V Lithium ion battery 

The voltage of an electric boat’s system, measured by the unit V (Volts), is a critical component of any electric boat because it directly affects the power available for the propulsion. A system’s voltage should strike a balance between power and safety as a voltage that is too high can be unsafe, while a voltage that is too low can result in impractical acceleration and speed. For 3-5m tenders and RIBS, a 48 V Lithium Iron Phosphate battery strikes this balance perfectly (assuming the manufacturer has maximised the system’s potential). ZeroJet, for instance, has developed a revolutionary 48 V system that delivers significant power despite the relatively safe voltage level. 

What is a LifePO4 battery? 

A LiFePO4 battery (also known as an LFP battery) is a type of Lithium ion battery with its own unique chemistry- the materials involved in the chemical reaction that produces the electric charge.  These use different cathode materials from other lithium-based compounds, nickel or lead:

• Solid but thin and porous electrodes and non-aqueous electrolytes with a higher packing density of active materials, unlike lead-acid and nickel-based batteries which use thicker electrode plates made of lead or nickel-based alloys and have a lower surface area per unit volume of active material.

• Graphite and carbon as the anode material, instead of nickel and lead.

• An inorganic, non-flammable electrolyte instead of a flammable, organic electrolyte.

This unique chemistry leads to a battery with a lower operating voltage, a stable and flat voltage profile and one with very low internal resistance. LiFePO4’s combination of Lithium ion battery technology and Lithium-iron phosphate chemistry makes them significantly lower maintenance, very energy dense, fast to charge, long lasting and safer than all other batteries on the market—overall the superior battery solution for a small electric boat.

Why choose LiFePO4 batteries for electric boats?

1. LiFePO4 batteries can store more power in less weight and they can release it quickly

Higher discharge rate than other Lithium-ion batteries  

LiFePO4 batteries are capable of delivering a higher power output than other Li-ion batteries because they have a higher discharge rate- the rate at which a battery can release its stored energy when in use. Plus, they are able to do this consistently over their lifetime without experiencing voltage drops or reduced power output. This means your electric boat will deliver energy quickly and efficiently, helping you to achieve higher speeds and faster acceleration.

Higher energy density than Nickel and Lead-based batteries 

As a type of Lithium-ion battery, LiFePO4 batteries can pack the same power in half the weight of Nickel-based and Lead-acid batteries because they have a high energy density - the amount of energy that can be stored in a battery per unit of volume or mass. This makes them ideal for small watercraft where low weight is crucial for achieving fast acceleration, high speeds, and getting up onto the plane easily. The compactness of LiFePO4 batteries also provides more on-board space compared to other batteries. For example, the use of LiFePO4 batteries in the ZeroJet-powered OC 350 has enabled it to boast a superior speed-to-weight ratio and weigh just 130kg yet seat up to 6 people. 

2. LiFePO4 batteries are the longest lasting batteries on the market

LiFePO4 batteries have a very long cycle life - the amount of times the battery can be charged and discharged before its performance starts to degrade. In fact, they can be charged around 3,000-5,000 cycles at 80% Depth of Charge (meaning you can recharge this many cycles as long as you charge before battery energy goes lower than 20% total energy). While other lithium ion batteries, nickel-based batteries and lead-acid batteries typically last just 500-1000 cycles. So, if you choose LiFePO4 batteries, you’ll get up to three times as much use out of your electric boat battery before you have to face the expense and down-time of replacing them. 

3. LiFePO4 batteries are more environmentally friendly than other battery types

LiFePO4 batteries are better for the environment than nickel and lead based batteries. This is because Lithium ion batteries do not contain hazardous materials such as cobalt and nickel. As explained throughout this article, they also last longer, are lower maintenance and deliver a greater range and runtime, meaning less replacements, waste and electricity used over time. 

Questions have been raised about whether electric boating really is better for the environment since the mining and extracting of Lithium ion batteries indeed produces emissions. Calculations however show that electric boats are indeed better for the environment, even when taking into account the emissions produced during the production of the batteries. Please see our article ‘Electric boat or combustion motor-which to choose?’ for more details on this.

4. LiFePO4 batteries are safer

LiFePO4 batteries are incombustible as they have a very low risk of thermal runaway- a phenomenon that occurs in batteries when the temperature rises to a certain point, causing a chain reaction that can lead to fire or explosion. They also do not contain any flammable electrolytes, instead using a non-flammable, non-toxic electrolyte that is much less likely to ignite under extreme conditions even if damaged or punctured. So you can be confident your friends, family and mothership are protected when using your electric boat and storing it on your home on the water. 

5. LiFePO4 batteries are lower maintenance and more resilient 

LiFePO4 batteries require significantly less maintenance than all other batteries on the market which means less time spent up-keeping the boat and more time enjoying it! This is of particular benefit to those boat buyers who value time and convenience. There are five main reasons for this:

Lowest self-discharge rate of all battery types 

LiFePO4 batteries can sit empty for longer periods of time without experiencing irreversible damage such as losing their charge or affecting their lifespan, unlike other battery types which can lose charge more quickly and which require more frequent charging to maintain performance (capacity and voltage). This is because LiFePO4 batteries have a low self-discharge rate - the percentage rate at which a battery loses its charge when it is not being used or recharged. This means you can leave them stored for longer periods of time before needing to charge just to keep them properly maintained. 

It’s worth noting that different brands of LiFePO4 batteries have a higher self-discharge rate than others. For example, Super B LiFePO4 batteries are designed to have an extremely low self-discharge rate of less than 3% per month. 

The self-discharge rate of a battery can also be affected by other factors, such as temperature and storage conditions, so it is important to follow the manufacturer's guidelines for storing and using LiFePO4 batteries to ensure optimal performance and longevity.

No Memory Effect unlike Nickel and Lead-based batteries 

LiFePO4 batteries will not lose their ability to hold a full charge over time regardless of when they are recharged in their discharge cycle or how frequently they’re charged. This is because they do not suffer from a memory effect where the battery develops a "memory" of its previous charge cycles and limits the amount of charge it can accept, unlike other batteries such as Nickel-Cadmium which require periodic deep cycling to maintain their overall capacity and lifespan.

Highest tolerance for deep discharge of all battery types

LiFePO4 batteries can handle deep discharges on a regular basis without suffering a drop in voltage, degradation of the battery or irreversible damage. This is because LiFePO4 batteries have a high tolerance for a deep discharge- when a battery’s charge is below 30% of total charge. 

To maximize the performance and lifespan of a battery, it's generally recommended to avoid deep discharges whenever possible and to recharge the battery before it reaches a low level of charge. For example, for optimal results, ZeroJet recommends recharging batteries used for their electric jet system before they reach a 20% discharge level.

Higher Charge Acceptance than other Li-ion batteries 

LiFePO4 batteries can accept higher charging currents, meaning they can be charged faster than comparative batteries without overheating and without experiencing significant voltage drop. This is because they lose a much lower percentage of total energy input as heat during the charging process.  In fact, their charging efficiency is 96-99%. On a related note, LiFePO4 batteries can also be charged to a higher voltage than all other battery types, meaning if you accidentally overcharge them, they are far less likely to experience damage. 

Highest tolerance to temperature of all battery types 

LiFePO4 batteries can operate at a much higher tolerance to extreme temperatures than all other battery types—meaning they can operate in a wide range of environments without risk of safety hazard or performance decline so you have more flexibility to take your boat out in certain locations or under certain weather locations. 

For further reading, please see these related articles: 

• Electric boats for sale- a 2023 buyer's guide to going electric [with checklist]

• Electric jet boat motor or electric outboard motor- which is best?

At the recent NZ Hi-Tech Awards Gala Dinner, we were very proud to be awarded the Hi-Tech Start-up Company of the Year prize!

The event was held at the amazing Te Pae Christchurch Convention Centre which opened in 2022 and has been designed as a ‘gathering place’ and a key part of the city centre regeneration. This was definitely the case with over 1,000 people attending the event from across the country and from overseas. This included the NZ Prime Minister who spoke about the importance of the tech sector for New Zealand- a theme echoed throughout the night, not only in terms of export earnings, but also with its social impact through inspirational organisations such as Recycle a Device and Digital Future Aotearoa, who both received awards for their work in this space.

ZeroJet was nominated as a finalist in 2 categories, and given the high standard of competition, we were hopeful but realistic about our chances. This proved to be the case when the Most Innovative Hi-Tech Hardware Product award went to Dawn Aerospace, a worthy winner thanks to their innovative green propulsion and space launch vehicles.

Given that the Start-up Company of the Year category was even more hotly contested with over 50 entrants, we were stunned to hear our name announced as the winner!

All-in-all it was a fantastic evening full of the southern hospitality you’d expect from Christchurch, and topped off with a closing set from the Jordan Luck band playing some Kiwi classics to send the crowd home happy!

Lithium batteries have become a very popular solution for a variety of electronics. They can be found in many devices from cell phones and laptops to all sorts of electric vehicles and boats. Lithium based batteries are in fact one of the best options to create the required energy for electric motors. But why has ZeroJet chosen to use Lithium-Ion Phosphate (LiFePO4/ LFP) chemistry batteries?

Battery Chemistry

Not all Lithium based batteries use the same chemistry. Here is a list of the 6 main types of lithium batteries used today:

• Lithium Iron Phosphate (LiFePO4)

• Lithium Cobalt Oxide (LCO)

• Lithium Manganese Oxide (LMO)

• Lithium Nickel Manganese Cobalt Oxide (NMC)

• Lithium Nickel Cobalt Aluminium Oxide (NCA)

• Lithium Titanate (LTO)

The different types of lithium batteries all rely on a unique active material and chemical reactions to store energy. Each type of lithium battery has its benefits and drawbacks, along with its best-suited applications.

Lithium Iron Phosphate (LiFePO4)

The Lithium batteries most frequently used in boating are of the LiFePO4 type. They have the great advantage of having a very stable cathode that does not give off any oxygen that could ignite when combined with lithium.

Material used in lithium iron phosphate batteries offer low resistance, making them inherently safe and highly stable, vitally important particularly when you’re using a ZeroJet-powered tender in remote corners of the world in potentially rough and unforgiving seas.

These batteries can handle high temperatures with minimal degradation. They have a long life for applications that have multiple embedded systems like the ZeroJet, or need to run for long lengths of time before needing to be charged. For example in the ZeroJet-powered OC350, you can travel up to 5 hours at low speeds (around 3 knots).

Super B Nomada battery cells

Our choice of battery is the Super B Nomada 12V 105 Ah cells which we install in series to get the required 48V for our system. Offering some of the most superior characteristics in the market, these cells have a lifecycle rating of 3,500 cycles and, unlike lead-acid batteries, the depth of discharge has a minimal impact on their lifespan. Super B rate their batteries to 100% discharging without damaging the batteries. In theory, this allows the user to discharge the batteries every day for nearly 10 years before they would need to consider replacing them.  

LiFePO4 batteries are more expensive upfront compared to other battery types, but cheaper long term because they last so long. They cost more upfront because the materials used to build them are more expensive. Super B models offer superior battery performance, and their certifications and warranty offer peace of mind. It is the benefit of years of continuous engineering improvement and proven experience supplying batteries to the harshest environments.

Battery price trends

Prices continue to fall as the adoption of LiFePO4 has increased, and as the market has moved away from the use of nickel-base batteries which contain expensive cobalt. On average, LiFePO4 cells were almost 30% cheaper than NMC cells in 2021, and this downward cost trend for LiFePO4 cells is expected to continue.

Electric boats will generally take between 1 to 36 hours to fully charge depending on the vessel. The required time to charge the system varies depending on the energy requirements of the battery and the available charge current output. Charging details can quickly get complex to understand so this article aims to cover key tips you can follow.

Charging times:

There are two factors that directly affect charging times:

1.       The state of the battery energy levels.

2.      The current which the charger can output.

The higher the amperage which the charger can provide, the quicker the batteries will charge.

Battery stage charging:

There are different stages of the charging cycle which need to be considered:

1. Bulk

The first stage in which the charger identifies the battery and its needs, then applies a high voltage/amperage charge to do the bulk of the charging.

2. Absorption

The battery has reached 80% and 90-95% of its capacity and begins to lower the input current to the battery. This is sometimes known as the "cool-down" cycle.

3. Maintenance

The Maintenance Charge (also known as "trickle" or "float" charge). In this stage, the battery has already reached 95%; the battery charger will continue to apply a steady current until the battery reaches 100% capacity - at that time, the charger will continue to monitor the battery and apply a charge if it detects any loss. By considering these stages you can choose the most appropriate charger. Selecting a charger that outputs the same voltage and current at all times without considering these stages could result in damaged cells if overcharged. 

For the ZeroJet system, we have a charger which meets these above requirements and is for both 230V & 110V AC applications. Automatic current control eradicates the need for annoying calculations or manual current adjustments. This means all you need to do is plug the EV style charge plug into the batteries with no further adjustments required.

The ZeroJet charger is small, compact, reliable and IP rated, and with a built-in LCD display on the system, you can see how much charge is required until full.

Taking care of your ZeroJet-powered electric boat batteries

Super B batteries offer some of the most superior battery characteristics in the market. These cells have a lifecycle rating of 3,500 cycles which in theory allows the user to discharge their ZeroJet nearly every day for 10 years before they would need to consider replacing them.  

However, having proper battery maintenance will preserve the longevity of your batteries. These are our tips for maintaining your batteries:

• Charge the batteries after every use. Don’t allow them to sit below 20% for long periods of time.

• Avoid under/overcharging your batteries. We have incorporated safety features in the ZeroJet electrical design to prevent overcharging however it's still important to know this will affect the overall life of the batteries.

• Always use the ZeroJet provided charger. Always turn off the charger after the charge cycle is complete.

• Don't push your battery to low depths of discharge. A battery that is usually re-charged when it drops to 30% of its capacity will last longer than a battery that is pushed to 10% or less of its capacity on a regular basis.

• Check the temperature of the batteries when charging. If excessive heat is noted, stop charging immediately. Do not charge while the battery pack is exposed to direct sunlight or while the boat is in the water (due to the potential movement). Temperature directly affects the voltage needed to charge the battery. In cold climates, more charging volts will be required to reach a full battery. The ZeroJet onboard BMS (Battery Management System) will account for this.

• SuperB have a minimum charge temperature of 0 degrees Celsius. If transiting polar waters it is advised to remove the batteries into an internal space for charging above the zero degrees threshold.

• If you seasonally store your boat, it’s highly suggested to avoid leaving the batteries in. It’s better to store them safely in a place without extremely hot or cold temperatures, especially over long periods of time.

• For storage it is recommended the batteries are charged or discharged to 80% before storing for the winter season or and long periods of no use. All systems should be turned off while the boat is in storage, and the charger disconnected.

• Clean battery terminals to prevent salt or dirt build up. Isolating the system and a quick fresh water spray and dry will generally do the trick.

This may seem like a long list but it is cheaper than maintaining a traditional outboard engine! Following these simple steps will help you to get the best performance and lifetime out of your Zero-powered system and batteries. If you have any specific requirements for your vessel charging system don’t hesitate to reach out to us.