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Small boat

Up the pleasure of sailing

Getting the boat off the trailer and heading out there on the water is just magic. Whether you’re going fishing, wakeboarding or island hopping for a few days, sailing means freedom. You want that same feeling when it comes to power. The freedom to charge your phone and play your favourite music wherever you are. Victron’s clever energy solution deliver that freedom for any small boat.

The Optimal Energy plan

Imagine you take a friend fishing for the weekend. The outboard engine takes your small boat to the middle of the lake. The day’s catch will be the dinner you cook before you camp for the night on a little island.

Let’s consider the Optimal Energy plan that helps you enjoy the trip in comfort.

Consumption

How much do you need?

Even a small boat relies on electrical equipment. Everything fitted in the boat will run on DC, but you’ll want an AC outlet to charge a phone or a laptop. All things electric use a certain amount of Watts. Adding up the Watts is only half of the story. Time is just as important. You might have 100 Watts in lights on board, but they’re on for a limited amount of time only. A little cool box will take 50 Watts, but is running all the time.

For inspirational purposes we’ve outlined 2 system examples based on ‘normal’ and ‘heavier’ use.

0.6 - 1.2 kWh / day

'normal' and 'heavier' daily consumption profiles.Read more

Read more

Example 1

The lights may use 100W an hour, but are only used 4 hours a day.
100W x 4 hrs = 0.4 kWh / day

Example 2

The coolbox uses 50W an hour but is on the entire day (actually cooling ½ of the day)
50W x 24hrs/2 = 0.6 kWh / day

Storage & conversion

How much energy should be stored?

You don’t want to run the engine all the time. It will scare off the fish. The solution is to store energy in a (house) battery, from which the inverter converts the stored power to 230V. The battery can be charged with shore power and from the alternator along the way. If you plan for trips that last days, make sure your battery has enough capacity to support you for 48 hours as a rule of thumb.

x 2

The storage capacity of a lithium battery should be two times the daily power consumption.

x 4

Due to its ±50% smaller discharge capacity, the storage capacity of a lead-acid battery should be four times the daily power consumption.

Conversion

The inverter should be sized to handle the average load continuously and should match the expected peak power current, which our inverters handle very well (on average 2 x their continuous current).

Generation

Where does the power come from?

You’ve got a couple of options to generate the power you need for your trip. First, there is shore power in the marina. Or - if you take your boat home on a trailer - you hook it up in the garage. Out on the water you can use the alternator on the boat’s engine.

Sources of power

Battery charger
10A - 30A
Alternator
35A - 70A

Power profile

Normal and heavier power profiles in kWh, based on the daily energy consumption, which should be in balance with the generation.

Storage batteries in Ah, double the capacity using lead-acid batteries.

Complete system

A closer look

How does the power profile translate into a system? Here is our recommendation for an average small boat.

House battery:

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AC devices

Devices you bring on board usually need an AC outlet. Think of:

  • Phone charger
  • Laptop
  • Drone batteries

Battery charger

As the name suggests: the battery charger recharges the boat’s battery when plugged into shore power. At the same time the Victron battery chargers will also power the boat’s electrics.

All Victron battery chargers operate automatically. You can safely keep them connected to the battery all the time, even when the boat is not in use. Waterproof chargers are also available.

Battery Monitor

A battery monitor is like a "fuel gauge" for your battery. It records how much power is consumed and charged. The battery monitor calculates the state of charge, remaining capacity and time till empty. The battery voltage does not give an accurate indication of how full the battery is. A battery monitor does.

Victron battery monitors keep track of historical data, like the number of charging cycles, deepest discharge, highest voltage, lowest voltage and so on. It will alert you to critical conditions such as low voltage or low charge. The smart monitor can even shut down the entire power supply to avoid expensive battery damage.

Choosing a BMV:

  • Choose a BMV 700 battery monitor if you want to monitor the house battery and don’t need a Bluetooth connection.
  • Choose a BMV 702 battery monitor if you want to monitor both the house battery and the starter battery, and you don’t need a BlueTooth connection.
  • Choose a BMV 712 battery monitor if you want to monitor both the house battery and the starter battery via BlueTooth on a smartphone or tablet.

BatteryCombiner

The Cyrix BatteryCombiner is the only safe way to connect the house battery to the starter battery (to start your boat’s engines). With a BatteryCombiner you can charge the house battery from the alternator without running the risk of draining the starter battery (which always should be ready to go). When other sources of power are available (eg. shore/solar/generator power), the Cyrix BatteryCombiner will allow bi-directional charging from the house battery to the starter battery.

When the Voltages of the starter and house batteries are the same, use a Cyrix: its current rating should be equal or bigger than the current rating of the alternator. If the house battery is Lithium and the alternators Amperage is smaller than the house battery, or when the Voltages of the starter and house battery are different: use a Orion or Buck-Boost.

BatteryProtect

Discharging your battery too far will damage it. Adding a Victron BatteryProtect will disconnect the boat’s electronics when the battery voltage drops below a pre-set level. It will also automatically reconnect everything when the battery is sufficiently recharged.

There is more to a Victron BatteryProtect. Built-in shutdown delays ensure vital electronics aren’t disconnected in error, i.e. when starting the engine causes a short drop in voltage.

BMS 12/200

The BMS 12/200 is a dedicated battery management system (BMS) that protects Victron Smart 12,8V LFP batteries against deep discharges, overcharging and high temperatures with up to 200 Amps maximum DC current. When critical values are exceeded, the BMS acts immediately: loads are disconnected physically in case of a deep discharge and charging is stopped when there is a risk of overcharging. High temperatures trigger an immediate end to both charging and discharging.

This is the only BMS that can be directly connected to an alternator, protecting them from overload/overheating. This works with a combination of an AB fuse (rated in accordance with the expected max load current of the alternator) and an internal programmable input (which limits the input current electronically to 80% of the AB fuse).

Please check your manufacturer for the maximum charging current of your alternator and size AB fuses of the BMS 12/200 accordingly, see manual.

When different Lithium batteries & higher voltages are used, other solutions are needed, such as the VE.bus BMS and Lynx-Ion.

See our bigger boat types to see a bigger Lithium system and BMS See more info on alternator charging Lithium (and not blow them up)

Boat engines

Small motor boats rely on their engine to get the job done. Their engine comes with an alternator to charge the engine batteries, drive fuel pumps, etc.

Once the starter batteries are recharged, the engines can also recharge the house battery and power the boats electronics. When the engine is used the majority of the day, there will always be enough energy generation to compensate the daily consumption. However, when the boat isn’t used over time, batteries might run dead eventually. Our battery chargers take excellent care of your batteries when in the harbour or garage.

Boat Electronics

A small boat will have several electronic devices; they all run of the house battery. Think of:

  • Boat control panel
  • Log/depth sounder
  • Chart-plotter or GPS
  • VHF Radio
  • Navigation lights
  • Pump – Bilge, deck wash
  • Fridge
  • Interior lighting
  • Music player
  • Bait Tank – Recirculating
  • Electric Fishing Reels/winches

House battery

The house battery supplies power to your boat’s electrical system. Choose a battery with a generous capacity as there might be long intervals between re-charges. Sometimes the starter battery doubles up as the house battery. If you opt for this set-up, make sure the battery is well protected against discharge. It will be hard to start the boat when the battery is flat.

For a house battery you can choose from two types: lead-acid and lithium. There are various reasons to favour one over the other. Here are a few common ones:

  • Choose Lead-Acid when:
  • Use occasionally
  • Lower purchase cost
  • Weight and space are not an issue
  • Normal charging
  • Choose Lithium when:
  • Use daily
  • Lower cost per cycle
  • Weight and space considerations
  • Fast charging

House battery

The house battery supplies power to your boat’s electrical system. Choose a battery with a generous capacity as there might be long intervals between re-charges. Sometimes the starter battery doubles up as the house battery. If you opt for this set-up, make sure the battery is well protected against discharge. It will be hard to start the boat when the battery is flat.

For a house battery you can choose from two types: lead-acid and lithium. There are various reasons to favour one over the other. Here are a few common ones:

  • Choose Lead-Acid when:
  • Use occasionally
  • Lower purchase cost
  • Weight and space are not an issue
  • Normal charging
  • Choose Lithium when:
  • Use daily
  • Lower cost per cycle
  • Weight and space considerations
  • Fast charging

Inverter

An inverter creates AC power from a DC source. It lets you use devices on board that need a regular AC outlet.

The inverter needs to be big enough to handle the maximum AC load you want to bring on board. If the load exceeds 375 VA, you might consider a combined inverter/charger instead. Models start at 500 VA.

Starter Battery

The starter battery is needed to start your boat’s engine. These batteries are different from house batteries and engineered to deal with a large discharge current. The starter battery should always be ready to go. It’s best to isolate the starter battery from all other electrical circuits on board, so it cannot be accidentally drained of power, with a BatteryCombiner.

Shore Power

Either in the marina or back home you’ll hook the boats charger up to shore power to recharge the battery. Shore power can also be used for maintenance and to run large AC loads.

VictronConnect

All Victron products on your boat can be monitored and controlled from the palm of your hand. Just connect the VictronConnect App via BlueTooth and you’ll have direct access to indicators like battery voltage and current. You can also turn devices on or off, as well as change their settings.

See what the VictronConnect app can do
System examples
Power consumption will vary from boat to boat and from owner to owner, even on small boats. Here are two examples - with a normal and a heavier daily energy consumption - of what an Optimal Energy plan for a small boat could look like.

Please note that many more factors come into play when designing and installing your optimal solution: your Victron Professional will gladly help you with that.

Normal
Heavier
Open motor boat, fishing boat, wakeboard boat ±19-26 ft.
Same boat but used more intense: longer away from home, more comfort or people on-board.
Consumption
Daily energy consumption
0.6 kWh
1.2kWh
Peak power
400 W
900 W
Storage & inverting
Victron Phoenix
12/250
12/500
BatteryProtect
65A
replaced by 12/200 BMS in case of 12,8V Lithium battery
100A
replaced by 12/200 BMS in case of 12,8V Lithium battery
House battery
110Ah 12V AGM
or 60Ah 12,8V Lithium
220Ah 12V AGM
or 100Ah - 150Ah 12,8V Lithium
BatteryCombiner
Cyrix 120A
or 12/200 BMS* in case of Lithium 12,8V
Cyrix 120A
or 12/200 BMS* in case of Lithium 12,8V
Generation
Alternator
35A - 70A
35A - 70A
Shore power rating 230V
16A
16A
Battery charger (from shore)
12V, 10A to 15A Blue Smart charger
12V, 20A to 30A Blue Smart charger
Extensions
Available extensions
Battery monitor BMV-712 Smart
Battery monitor BMV-712 Smart
Show full list
Dive into the world of marine energy

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Our well established global network of local Victron Professionals is dedicated to help find an optimal solution for your challenge.

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At Victron we find it essential that customers are serviced and supported quickly and competently. This is why our global network of Victron Professionals pack the highest level of technical know-how and are committed to deliver repairs as fast as possible.

So you can start or continue your journey, wherever you’re headed.