What boats are electric motors suitable for? What is the average speed underneath them? How many hours does the battery last? Is it true that all electric boat motors are the same? Can they be considered as a replacement for the internal combustion engine? A standard heap of questions that befalls everyone who plans to acquire an electric motor for their boat. So we decided to hit the test on the topic of the day. The idea is simple: take two inflatable PVC boats of different lengths, a pair of traction batteries and several electric boat motors, and then test them on the water. The tasks are clear - to answer the questions listed above.
What have we done?
We took boat electric motors four different manufacturers, most widely represented on the market today - Minn Kota, Outland, Haibo and Flower. Additionally, we were able to test two models from the same manufacturer with different traction characteristics - Outland TP44 and TP34, in order to find out how they differ, except for the numbers on the body. Some of the tested outboard electric motors were completely new, others had been in use for a long time. This did not bother us at all, but, on the contrary, even interested us. I really wanted to raise another question: how the performance characteristics of electric motors change over time. Then we went to a reservoir, where all this stuff was subjected to the most sea trials. Let us note that our goals were not to obtain dry statistical material. We wanted more - to form an informed opinion on how different outboard electric motors behave on different pvc boats.
Materials
For testing, we chose two inflatable pvc boats from Mneva, model Cayman. The first is 330 cm long, the second is 380 cm. There were good reasons for this.
Firstly, the “Cayman” is a very popular model, produced for the second decade - in general, a classic PVC boat with classic shapes and design (photo 1).
Secondly, this model has a lot of imitators among other companies, therefore, by choosing it, we automatically overlap wide range from the boats found on our waters. It is no coincidence that these two standard sizes - 330 and 380 cm - are the most popular and universal, applicable both on small forest lakes and in open spaces large rivers or reservoirs. In addition, these are already serious, rather large PVC boats - I was curious how our boat electric motors would cope with them.
For tests, we took two batteries with capacities of 95 and 100 Ah (photo 2), both acid and traction.
And if the “weaving” was practically new - it only had a couple of fishing trips under its belt, then the “95th” was in use for more than three years and survived about two hundred charge cycles, almost half of its service life. Thus, we wanted to see how the characteristics of the tested electric boat motors would change in combination with such different batteries.
Speed measurements were made using a Garmin Oregon 200 household GPS navigator (photo 3); to determine the current and voltage values in the circuit while driving, we used a Ts4324 voltammeter (photo 4).
Place and conditions for testing boat electric motors
For testing, we chose a very popular vacation spot among Minsk residents - Zaslavskoye Reservoir, as it is also called, the Minsk Sea. So that the reader can imagine the possible wave height or wind strength, which, of course, left their mark on the test results, I will describe our sea. Its water surface area is about 31.1 km2. Length - about 10 km, width - 4.5 km. Standard depths are 3.5 m, although there are also 8 m. On the test day, the weather was partly cloudy with a light northwest wind at a speed of 3-5 m/s.
About electric boat motors
Every self-respecting manufacturer of electric boat motors has at least four models in its line, differing in power, and, consequently, traction characteristics, overall dimensions and weight.
Thus, the thrust of the smallest models in the line is less than 13 kg (about 0.38 hp) and they are designed, as a rule, for boats with a total curb weight of up to 600 - 800 kg, while the most powerful examples of electric boat motors develop thrust up to 25 kg (0.85 hp) and can be used on ships with a displacement of up to 1.5 tons or more. We deliberately chose for testing electric motors with similar traction characteristics - these are light models for small and medium-sized boats, with stated figures of 32 - 34 lbs, i.e. 14.5-15.5 kg.
Tested outboard electric motors at first inspection
Minn Kota Endura Pro 32 electric boat motor(photo 6). Maximum push thrust 32 lbs = 14.5 kg (in 5th gear), power 0.43 hp, designed for boats with a curb weight of up to 680 kg, rod length 76 cm. Electric motor weight according to the “manual” - 7.3 kg. Number of gears: 5 forward + 3 reverse. The propeller is two-blade. Features: rod made of composite material. And, of course, one cannot help but say that Minn Kota is a recognized trendsetter in this area. Hence the quality of assembly and materials. The electric boat motor we tested has been in use for more than three years. And, which is typical, it does not require any repairs to this day.
Boat electric motor Flover F33T(photo 7). The thrust in the clean and jerk is, of course, 33 lbs, which is 15 kg. Power 0.44 l. With. Designed for boats with a curb weight of up to 800 kg. The length of the composite rod is 75 cm, the stated weight is 6.8 kg. Number of gears 5/3. The propeller is two-bladed. The naked eye can see the resemblance between Flover and Minn Kota (photo 8). Well, this is intriguing - will the similarity be only superficial? Features: the model has an LED indicator of the battery charge level (photo 9). Reviews about this option are very contradictory - from enthusiastic to negative, due to the increase in electricity consumption by the electric motor. Flover F33T came to us in its original packaging.
Outland TP 34 electric boat motor(photo 10). Maximum thrust in clean and jerk 34 lbs = 15.4 kg, power 0.47 hp. With. The manufacturer claims that it is designed for a boat's curb weight of up to 1100 kg. Claimed weight: 6.7 kg. Bar length: 78 cm. Number of gears: 5/2. The propeller is two-bladed. At the time of testing, it had been in use for more than two years. There were no problems during use. Notice how the stated values differ permissible weight boats with which the Outland TP 34 and Minn Kota Endura Pro 32 are applicable: the difference is almost double! 1100 versus 680 kg. This is intriguing, since the remaining declared parameters of these two outboard electric motors, if at all, differ, are not significant. It turns out that either someone is playing it safe, or someone is giving unrealistic numbers - we hope this will become clearer in the test.
Outland TP44 electric boat motor(photo 11). Maximum deadlift in clean and jerk is 44 lbs = 19.95 kg. Power 0.59 l. With. The maximum displacement of the boat is up to 1350 kg. The weight of the boat electric motor according to the passport is 9.55 kg. The design is similar to the younger model TP34. At the time of testing, the electric motor had not been in use for a full season and did not cause any complaints. Among the features are a metal rod 91 cm long and a three-blade propeller, which suggests that the electric motor is applicable on fairly large boats with a high side. It is this unit that goes beyond the “light class” of boat electric motors chosen for testing.
Boat electric motor Haibo ET 34L(photo 12). Boat electric motor by design and appearance simply identical to Outland. Moreover, we would venture to assume that they were produced at the same plant - well, just twin brothers! Therefore, we were not at all surprised that the declared characteristics of these two electric motors are the same: maximum push thrust 34 lbs = 15.4 kg, power 0.47 hp. s, boat displacement up to 1100 kg. The length of the rod is 78 cm, the weight of the electric motor is 6.7 kg. Came into our hands second-hand - about three years without complaints of indisposition. The intrigue is that rumors are actively circulating in the Internet community that, supposedly, Haibo, when moving at the last, fifth speed, “makes” all its classmates and even some electric motors, which is more powerful. This, of course, we will also clarify today.
Let's start testing boat electric motors
First, we weighed each of the electric boat motors we tested. Measurements were made on Nevskie table scales (photo 13) with a limit of 15 kg. As can be seen from Table 1, our results differ slightly from those stated by the manufacturer. The biggest difference with the Minn Kota Enduro Pro 32 is that it is more than 700 grams lighter, which, you see, is significant. Apparently, the Americans underestimated the lightness of the composite bar.
Why was it necessary to measure the current? The point is this: all other things being equal, of the two electric boat motors, the faster one will be the one that consumes higher currents. That is, this table gives hints for future high-speed tests and will allow us in the future, together with the results of measuring the speed of PVC boats, to determine the efficiency of the tested boat electric motor. What should you pay attention to here?
Firstly, from Table 2 it is clear that the current values in the corresponding gears of electric motors of the same class, if they differ, are insignificant. This indirectly indicates that their speeds should be approximately equal, other things being equal. If a serious difference is found, it means that the efficiency of boat electric motors is different.
Secondly, note that the Minn Kota Enduro Pro 32 in 5th gear draws almost the same current as the most powerful Outland ET 44 in 4th gear. Do you see where we're going with this? Let's check if they have the same speed.
Thirdly, Haibo ET34L and Outland ET 34 have identical current values. This is another reason to claim that these electric boat motors have one parent.
Comparing the Minn Kota Enduro Pro 32 and the replica from Flover, you can see similar data. Differences occur only at first, second and fourth speeds. At the same time, we must take into account the fact that Flover is most likely copying the new ZOS motor, which appeared in 2012, while our Minn Kota electric motor is three years old.
Test of electric boat motors for maximum speed
Let us recall that the speed measurements were made using a Garmin Oregon 200 GPS navigator. Of course, we cannot avoid the errors of GPS devices for non-military purposes here. However, all subjects were in equal conditions. The measurements were carried out in the following way: inflatable boat - pvc The Cayman 330 was equipped with a test electric motor, and then covered the distance between two given points on the reservoir. For the entire series of tests, these points, and, therefore, the direction vector of movement, remained unchanged - in our case, this is the distance from the pier to the island, which was equal to 0.34 km according to the navigator. Moreover, when moving from the pier to the island, the wind prevailed in the tail direction, and back - in the back direction. This coast-island-shore route was overcome in each of the five gears in turn, and we placed the value of the maximum speed (in km/h) during the passage of the track in Table 3.
All tests were carried out three times - with one, two and three passengers on board - these values correspond to columns with a load of 80, 160 and 220 kg, respectively. For the sake of the purity of the experiment, we note that we did not take into account the mass of the battery and equipment in the boat, although this is still about 40 kg. In addition, we recorded the speed with and against the wind - and derived the values average speed, which you can also see in Table 4 for each case.
As it should have happened, most powerful electric boat motor Outland TP44 showed the most high speed based on the results of all tests. However, we were quite surprised by the fact that the Haibo ET34L came very close to it with a load of 220 kg, and with a load of 80 and 160 kg in 5th gear it was even a little faster! It is also curious that the Haibo ET34L clone - the Outland TP34 model - showed worse results than the leaders. It turns out that the insides of Outland and Haibo are still different. Overall, the results were pretty even. The only thing that goes beyond this nice series is the speed values we obtained for the Outland TP44.
Please note that when driving in all gears, with the possible exception of 3rd and 4th, the maximum speed values were recorded, paradoxically, at the maximum load of the boat. How to explain this? It seems that the answer lies in a combination of reasons: starting from changes in better side in the hydrodynamic parameters of the boat when achieving optimal loading to the imperfection of measuring instruments and techniques. In any case, we assume that the test conditions remained unchanged for all models.
The slowest result, as expected, was shown by the smallest model, Minn Kota Endura Pro 32. However, let’s not rush to final conclusions; let’s wait until the second, no less important test, “Electricity Consumption.”
Only Flower 33T was not mentioned. In general, he has very good results. Boat speeds under this outboard motor are exactly where they should be: between the Endura Pro 32 on one side and the more powerful ET34L and TP34 on the other. Next, we repeated the tests of boat electric motors, only on a larger Cayman 380 boat. This time we did it only once - with a load of 160 kg, in order to compare the results with a smaller boat.
So, you have decided to purchase an electric boat motor. But which model should you choose? What characteristics should it have?
Let's try to figure it out.
Unlike gasoline engines boat electric motors are divided by power, measured not in kilowatts or horsepower, but by the thrust they develop (lbs).
Traction is the main characteristic of an electric motor; it is the force that a given motor is capable of developing. The craving is constantly effective force resulting from the operation of the electric motor, it also depends on the shape, pitch and size of the screw, as well as its speed of rotation. In turn, the propellers that are equipped with electric motors are designed to develop maximum acceleration immediately after starting the electric motor.
As a rule, the amount of thrust is indicated in the name of the boat electric motor model. However, it should be taken into account that the name often uses the American unit of measurement - the pound, which must be multiplied by 0.45 (1 pound = 0.45359237 kg) to convert it to the metric system we are used to.
Example: The Moratti Bady 30 electric motor has a thrust of 30 pounds or 13.5 kg.
The required amount of electric motor thrust is directly dependent on the displacement of your vessel. That is why, when describing the technical characteristics of a particular model of an electric boat motor, the maximum displacement and dimensions of the boats on which they are recommended to be used must be indicated.
To make it easier to determine the electric motor thrust that is suitable for your boat, the chart below has been compiled:
This chart is very easy to use. For example, your boat weighs 450 kg. With cargo, an electric motor, fuel supply (battery), and passengers, the weight (displacement) of the boat reaches 850 kg. We mark this displacement value on the horizontal axis. Next, we find on the vertical axis the corresponding thrust value, which is measured in pounds, we get a value of 40 lbs. An electric motor with exactly this thrust will be optimal for your boat.
What if we install an electric motor with more thrust - will our boat go faster?
Let's try to answer this question. First, a little theory. First of all, it is necessary to take into account that the boat, controlled by an electric motor, moves in displacement mode, that is, it is kept afloat by the Archimedes force, as a result of which it is partially immersed in water. In this mode, it is impossible to develop high speed due to the high water resistance.
The correspondence between the size of the vessel and the speed of its movement is determined through the Froude number (formula). For displacement vessels, the Froude number is always less than one, usually 0.2-0.3.
Maximum speeds boats moving in displacement mode are shown in the table below:
Now it becomes clear why electric motors are not for fast racing on the water, but are an ideal option for lovers of quiet, calm fishing.
Thus, by installing an electric motor with high traction on our boat, we can achieve an increase in speed of a maximum of 1-3 km/h, but this will come at a significantly higher cost in the cost of both the electric motor and the battery. Moreover, thrust and speed are related nonlinearly - an increase in thrust by 30% increases speed by only 10%. And in any case we will not be able to exceed the limits indicated in the table above.
Having chosen an electric motor, you need to decide on its power supply – the battery.
All boat electric motors are divided into two power classes - 12 and 24 Volts. There are few options here - at 12 Volts we connect one battery, at 24 Volts - two batteries are connected in series.
Batteries are divided into starting and traction batteries.
Starter batteries are used in cars and to start outboard motors. Their task is short time(at start) produce a significant current, then the internal combustion engine begins to work. If you use starting batteries as the main power source for electric motors, when deeply discharged, they will discharge quite quickly.
Traction batteries are specially designed for deep discharges, for operating mechanisms driven by electricity and are most suitable for powering boat electric motors.
When choosing a specific battery, you should know how often you plan to use it. And of course, price plays an important role. The car starter battery will last you 5-10 trips out on the water. The traction battery will last much longer, although they cost 2 times more. But in this case, these costs are absolutely justified.
Determining the power of the battery is directly related to the thrust of your electric motor. The table below shows the operating time of a 100 A*h battery for different motors.
That is, one charge of a battery with a capacity of 100 A*h, when operating it at 50% power to power an electric motor with a thrust of 35 LBS, will be enough for you for 6 hours of CONTINUOUS running.
Of course, the figures given are indicative in nature, since they do not take into account the design features of your electric motor and boat.
Motor control system.
Designers from leading manufacturers have tried to make operating an electric boat motor as easy as possible to allow you to fully concentrate on fishing. Many accessories and additional devices are presented to users.
You can choose hand or foot control according to your taste. Foot-operated motors are equipped with pedals with a momentary power switch and allow you to be completely hands-free, but the pedals and wires clutter the deck of the boat, which can be inconvenient if you are not fishing alone. "Rukniki" have a telescopic tiller (with variable angle tilt for fishing while standing) and push-button control.
Many modern models are equipped with special systems for adjusting engine power depending on the speed of movement, which increases the output from one battery charge by four to five times. Autopilot systems and remote control of electric motors are also already becoming common features.
How to care for an electric boat motor?
The electric motor, like batteries, must be stored in a clean and dry condition. If you used it in sea water, you must first thoroughly “desalinate” the motor and rinse it completely in fresh water. If you are initially using an electric motor designed for use in salt water ( distinctive feature This type of motor is white), washing is advisable, the main thing is to monitor the condition of the anti-corrosion anode, which is always used when operating electric motors in salt water and is usually attached behind the screw on the motor housing, or above the sternwood. The anode surface must always be clean. It is advisable to store the motor in a dry and warm place.
Hello readers! Have you ever thought that one unit of measurement can be used in different contexts and mean different things? Don't be afraid, I'm not crazy and I'm not trying to put smoke in my eyes, today we will look at the meaning of lbs, what is it? Where can you most often find such an abbreviation and what does it mean?
Lbs as a unit of measurement
The first time I became acquainted with the Lbs indicator was completely by accident. If you read my blog, you probably know that I am fond of sports and have been exercising regularly for more than one year. And as soon as the first electronic scales appeared, I could not resist purchasing them.
Having opened the box, pressing a few buttons (I don’t remember exactly how old I was then), I turned on the scales and immediately decided to use them for their intended purpose. Imagine my surprised eyes when the number 170 appeared on the screen. I was shocked, and only after a few seconds I realized what the catch was. The scales did not show Kg, they showed pounds. It was not clear how to convert lbs to kg.
Conversion to kg
- Pound (from Latin pondus - weight, weight) is a unit by which mass and weight are measured.
- The classic pound used in America and England is equal to 16 ounces or 453 grams;
- Troy (English pharmacy) pound is equal to 12 troy ounces or 373 grams.
- The Latin word "libra" means a unit that predates the pound; in English-speaking countries the abbreviation lb is still found. Many people have probably heard about the monetary unit pound sterling, which is represented by the symbol £, which also goes back to the word “libra”.
To convert Lbs to kilograms, you need to multiply the number of pounds by 0.453 kg.
Most often this abbreviation is used in the following concepts:
- Location-based service is a type of information and entertainment service based on determining the current location of a mobile phone.
- The unit of weight is lbs (the correct designation in singular and plural is lb).
- Lectori benevolo salutem. (L.B.S.) Greeting to a Favorable Public (Latin.) A formula of author etiquette that was used many years ago.
What is lbs tracker
Location-based service is an information and entertainment service designed to determine the current location of a mobile phone. The visualization capability of a modern mobile phone (often used in a smartphone) will allow you to display it on the screen, which will allow you to use the tracker to solve a variety of business problems, navigation and entertainment.
LBS does not necessarily need to use the technological features of GLONASS, GPS or other satellite systems to determine location. The location where a mobile phone is located, for example, can be determined using previously known information about where the base stations of mobile communication networks GSM, UMTS, etc. are located, as well as information about the location of a Wi-Fi access point.
In each case, the same method for calculating the position is used - a reverse geodetic intersection.
GPS And navigation
Today, the GPS monitoring system serves as a reliable tool for controlling and optimizing the operation of transport. It allows you to get reliable information about where the car is, how many kilometers it has traveled, what its fuel consumption is, etc. Do you use the GPS service? I think all readers of this article will answer: “Yes.”
The GPS monitoring system is convenient not only for drivers, but also for company managers, because based on the analyzed data, it is possible to make an important management decision and coordinate work on more high level, and dispatchers and forwarders will be able to see the real and most current picture in order to promptly respond to any non-standard situation.
But what to do if the key technology to determine locations - GPS no longer functions, or was negatively affected by the driver himself and did it on purpose? In such a force majeure situation, the only alternative is the LBS monitoring system, which has recently been supported in many existing systems.
Operating principle
Based on the principle of operation, LBS monitoring resembles GPS, but the signal source is not a satellite, but the nearest GSM station of a cellular operator.
Therefore, if for some reason the GPS signal is lost, you will quickly determine the location of the vehicle wherever there is a cellular network (and the more sticks on your phone that point to the signal, the more accurately you can determine the location).
Monitoring is also used to control the movement of objects in places where a GPS signal is not available: this could be an underground parking lot, a tunnel, a concrete garage.
Determining coordinates as accurately as possible using LBS technology is not as realistic as using GPS. This all depends on the coverage density and network of the base station, what the current local radio conditions are and the cell configuration.
For example, in the central large European town the coordinate error can vary in the range of several tens of meters, on the outskirts and in a small city - up to hundreds of meters. In villages or deserts, accuracy may decrease by several kilometers. But, according to my personal observations and calculations, data from a cellular station will make it possible to quite accurately show on the map which road the object was traveling on. The accuracy of the mileage, of course, cannot be calculated, but the approximate location, as well as the approximate trajectory of movement, can be shown.
Useful addition
We can come to the conclusion that, despite the fact that the functionality of LBS monitoring is inferior to GPS in terms of specificity and accuracy, as you have probably already noted to yourself, it can be considered a worthy assistant and a “second possible option” if suddenly the GPS signal is absent or interrupted by interference .
Therefore, if you do not want your cars to be overlooked, always keep your finger on the pulse - feel free to find on the Internet how to properly configure the LBS detector. You can conduct monitoring manually or automatically.
By the way, LBS services are also actively used in the Yandex.Traffic application. If a person’s location is continuously updated, and a few minutes ago he was in the middle of the road and does not move, you just have to sympathize with him: a friend is stuck in a kilometer-long traffic jam.
Various schemes have been invented around the world to track the situation on the road: operational reports, cameras and detectors that automatically analyze the image, and, of course, software that LBS services use.
If you still have any questions about the topic under consideration, please write in the comments. I will be glad if you become a subscriber. See you soon!
Text— Agent Q.
Which electric motor for a boat is considered the most powerful? The one that draws more power from the battery? Or maybe one that easily pushes even a heavy boat forward, consumes little current and runs on batteries for a long time?
What is the power
The propeller converts the engine energy into force, which, overcoming the resistance of water and air, moves the boat forward at the selected speed. In this case, part of the energy is lost and the power used to move the vessel is always less than that consumed by the engine. Rt - water resistance; Pe - effective (towing) power; Pt - propeller power; Pv - shaft power; Pb - engine power. T - thrust; V - speedA common criterion for comparison is important. The powers measured in different places differ significantly from each other. Motor developing 4 liters on the shaft. s., on the propeller it produces only 1 hp.
Outboard motor manufacturers use different types power. There are shaft power, power consumption and even thrust. Therefore, before comparing different electric motors for boats, you need to bring the available data to a “common denominator”
Power consumption, on the shaft and on the screw
Power consumption– often used as a characteristic of an electric motor for a boat (power = current x voltage). Expressed in Watts or horsepower. Manufacturers of gasoline or diesel outboard motors do not use this type of power. However, for an internal combustion engine, power consumption can also be calculated by multiplying the calorific value of the fuel by its consumption.
![](https://i2.wp.com/fisherninja.ru/knowlege-base/wp-content/uploads/2015/11/power-losses.jpg)
Shaft power– used by manufacturers of outboard gasoline boat engines. This type of power is calculated in the same way as a car (power = torque x angular speed). Measured in horsepower or watts. Shaft power takes into account losses in the gearbox, but does not take into account losses on the propeller, which range from 20 to 70%.
Prop power– has been a generally accepted engine characteristic in shipbuilding for more than a hundred years. Takes into account all power losses and determines the energy transferred to the boat by the engine.
During rotation of the propeller, a lifting force is generated on the surfaces of the blades. The component of this force directed along the axis of motion of the boat is called thrust or thrust. It characterizes that part of the lifting force that pushes the ship forward.
The net power produced by a boat propeller is equal to its thrust multiplied by the boat's current speed. Manufacturers always indicate the maximum thrust value in the characteristics of electric motors. It is impossible to draw a conclusion from it about the power of the electric motor on the propeller without installing sensors and taking measurements.
Thrust is determined through testing in which the boat is connected to a pier with a dynamometer and an electric motor is forced to push it forward. The test is carried out in calm water, in calm weather, at a sufficient depth and distance from the shore. For electric boat motors, thrust is most often expressed in pounds force (lbs).
Name | Torqeedo Travel 1003 CS | Minn Kota Traxxis 55 |
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Power consumption, W | 1000 | 600 |
Operating voltage | 29,6 | 12 |
Propeller power, W | 480 | - |
Thrust, lbs * | 68 (* 102 lbs according to trolling motor manufacturers' methods) | 55 |
Total efficiency, % | 48 | - |
Weight without batteries, kg | 8,9 | 13,6 |
Weight with battery, kg | 14,9 | - |
Maximum boat weight, kg | 1500 | 1500 |
Gasoline and electric motors for boats
Electric boat motors can develop the same thrust as internal combustion engines while having significantly less shaft power. This is due to the different shape of the torque curves of electric and gasoline engines. In an internal combustion engine, the torque curve has a pronounced peak, due to which the maximum torque is available only in a limited range of shaft speeds. The dependence of torque on revolutions of an electric motor is much flatter and is sufficient at any speed
![](https://i0.wp.com/fisherninja.ru/knowlege-base/wp-content/uploads/2016/07/speed-torque.jpg)
The flat torque characteristic allows the installation of more efficient propellers on electric boat motors. The propeller efficiency of some electric motors for small boats is three times higher than that of gasoline outboard engines in the same class.
To make it easier for the user to compare gasoline outboard motors, which have a specified shaft power, with electric motors, Torqeedo has introduced the concept of “equivalent power”. Marked "3 HP equivalent" provides the same propeller power as a 3 HP petrol outboard engine. Although in this case the power consumption and shaft power of the electric motor can be significantly lower.
Torqeedo Cruise 2.0 | Typical boat electric motor | Outboard petrol motor 5 hp | |
Power consumption | 2000 W (2.7 hp) | 2000 W (2.7 hp) | — |
Shaft power | — | — | 3700 W (5hp) |
Prop power | 1112 W (1.5 HP) | 660 W (0.9 HP) | 995 W (1.4 HP) |
Power loss in a boat electric motor
The overall efficiency of the power plant on a ship with an internal combustion engine is 5-15%. For a boat with an electric motor, such an indicator is an unaffordable luxury. It is believed that a boat electric motor operates efficiently if, taking into account losses on the propeller, its efficiency is about 50%. In this case, the efficiency of the electric motor must be at least 80%, and the efficiency of the propeller at least 63%.
![](https://i1.wp.com/fisherninja.ru/knowlege-base/wp-content/uploads/2015/11/motors-compare.jpg)
System voltage
Power loss is proportional to the resistance of the conductor and the square of the current flowing through it. If the current doubles, the losses quadruple. If the current increases by a factor of ten, the losses increase by a factor of a hundred. You can reduce current and losses by increasing the voltage in the circuit.
The generally accepted voltage for powerful boat electric motors today is 48 volts, but 24-volt electric motors are also suitable for small boats. With a current of 50 A, the maximum power of the electric motor in a 12-volt system will be 600 watts, and in a 24-volt system – 1200 watts
The second way to reduce losses in a DC circuit is to increase the cable cross-section. Properly selected cable increases the efficiency and safety of the electrical system, eliminates local overheating and reduces energy loss. For example, the maximum current of 2.0 is more than 80 A (power consumption 2000 W at 24 V). If you connect an electric motor to batteries located at a distance of five meters from it with a cable with a cross-section of 25-35 mm², then the losses will be 17 W, which corresponds to 0.8% of the total power or 3.4 W per meter of cable.
Electric motor
Electric motors used in electric boat motors can be divided according to several criteria:
- Method for creating an alternating magnetic field
- Method of excitation of the main magnetic flux
- Design
![](https://i0.wp.com/fisherninja.ru/knowlege-base/wp-content/uploads/2016/07/minnkota-armature.jpg)
An alternating magnetic field in an electric motor is created using mechanical or electronic commutation. In a classic motor, fixed brushes slide along rings located on the shaft and switch the direction of current in the windings depending on the position of the rotor. The brush assembly converts direct current from an external source into alternating current and serves as a mechanical inverter. Over time, the brushes wear out, begin to spark, and additional resistance arises at the point of contact with the rings. Losses reduce the efficiency of the motor and increase its current consumption.
In a brushless motor, an alternating field creates a current obtained from a high-frequency DC-AC converter. Brushless motors have no losses due to brushes, are more efficient and do not require maintenance.
The primary magnetic flux in the motor can be created in two ways - using permanent magnets or current in the field windings. Electromagnetic excited motors are cheaper, but compared to permanent magnet models they are heavier and take up more space. Losses in the field coils reduce the efficiency of the motor and increase its energy consumption.
![](https://i1.wp.com/fisherninja.ru/knowlege-base/wp-content/uploads/2016/07/torqeedo-slice-450.jpg)
Structurally, brushless motors come with an internal or external rotor. In the traditional version, the rotor rotates inside the stator. Due to this, the engine is cooled better, but produces relatively little torque.
In modern engines, the rotor is located outside the stator. There are magnets on the rotor, and windings on the stationary stator, which create an alternating magnetic field. The torque of a motor with an external rotor is twice as strong. Because the outer rotor has a larger surface area, it accommodates twice as many magnets, further increasing torque. The torque increases even more when rare earth magnets are used instead of conventional ferrite ones.
Powerful boat electric motors are equipped with a synchronous brushless permanent magnet motor with an external rotor. It produces more thrust than a conventional electric trolling motor, weighs less, uses less current, and has longer battery life.
Screw
A propeller with a large diameter, pitch and low rotation speed has high efficiency. However, only a motor that develops high torque can operate such a propeller. In this case, the difference between the highest and lowest torque values of the engine should be minimal.
Most propellers of gasoline and electric motors used on small boats are based on tests carried out back in the 1940s to 1960s of the last century. The general design principles that emerged then are systematized in the form of tables and graphs and are still used by manufacturers today.
A different approach is used when developing propellers for Torqeedo electric motors. First, a three-dimensional model is created on a computer, and then the pitch and curvature of the propeller profile are optimized for each section, taking into account the conditions of water flow changing along the diameter. Screws of this type are called variable pitch and profile screws. Their losses are lower and their efficiency is higher.
Battery for electric motor
The optimal energy source for a modern outboard electric motor is a lithium battery. Compared to other types of batteries, lithium batteries store more energy, provide high discharge current without loss of capacity, and withstand many more charge-discharge cycles.
Power consumption, W | 1000 |
Propeller power, W | 480 |
Outboard gasoline engine comparable in propeller power, hp | 3 |
Comparable outboard gasoline engine, hp | 4 |
Maximum overall efficiency, % | 48 |
Rated voltage, V | 29,6 |
Static thrust, lbs | 68 |
Static thrust calculated according to trolling motor manufacturers' methods, lbs | 102 |
Capacity of built-in lithium battery, Wh | 915 |
Total weight, kg | 14,9 |
Weight without batteries, kg | 8,9 |
Weight of built-in battery, kg | 6,0 |
Deadwood, cm | 62,5 |
Standard propeller (v – speed km/h at p-power W) | v9/p790 |
Maximum propeller speed, rpm | 1200 |
Control | Tiller |
Forward/reverse. Variable speed | Yes |
Built-in computer with display and GPS | Yes |
However, unlike lead-acid batteries, lithium batteries require a complex electronic monitoring and balancing system. However, failure of the BMS components itself creates a problem for battery safety. To eliminate unforeseen situations, critical BMS parts in lithium boat batteries are duplicated. Just like it is done in automotive, aerospace or medical technology.
In the industrial production of boat lithium batteries, only cylindrical cells in a metal shell are used, which are welded together and then installed in a plastic or metal case. High-quality rechargeable batteries have a housing with a protection class of IP67. The waterproof housing protects the BMS boards from corrosion and prevents the formation of electrolytic gas.
Convenient boat electric motor
High technical specifications It is easier to evaluate a boat electric motor when it is convenient to use. A modern electric motor on a boat is controlled by a microprocessor, so all information about its condition exists in digital form and is easy to present to the user. Part of the overall control system for a boat electric motor is the BMS. She knows everything about the battery. What charge is left in it? What is its temperature? How much current does it deliver? The data it collects is shared by the BMS with other system components, which use it to calculate the boat's current speed, power consumption, and remaining range.
The user receives information processed by the on-board computer on the display. The remaining range in miles or kilometers changes in real time. When the battery power is low, the computer beeps and warns you that it is time to turn the boat around and return to shore, or reduce speed to increase your cruising range.
Ask a question
and get advice on outboard electric motors, batteries or chargers for a boat or yacht
What engine power is needed for a particular vessel and at what speed will this vessel move?
This question most often arises when fishing in reservoirs where the use of gasoline engines is prohibited or when choosing a trolling motor on boats with an outboard or stationary engine with an angle column.
Let's start in order.
All electric motors do not have such a characteristic as the well-understood “POWER in horsepower”.
Instead, a concept such as “traction” is used. Thrust is the force that the motor develops. It can be visually measured quite simply.
We take scales (such as a steelyard) and attach a halyard from the boat to one side, and a halyard to the pier to the other side (the pier must be stationary). We start the engine and look at the steelyard readings - this is traction.
Example 1
Let's assume that your boat weighs 100 kg, add to this weight the load, the weight of the engine, the weight of fuel, luggage and the weight of passengers. We will get approximately 200-250 kg. On the horizontal axis, the graph starts at 500 kg.
We accept this value and find the required thrust of the electric motor on the vertical axis (in pounds, as a rule, this corresponds to the numbers in the motor model). In our case, it turns out to be 33-35 LBS.
Example 2
Our boat, including the engine load, weighs 1500 kg. We do the same. We find the weight and the corresponding thrust value on the horizontal axis.
In our case, this will be approximately 55-60 LBS.
The engine thrust has been determined.
But, two questions arise: At what speed will the ship move and if you install a more powerful motor, will the ship move faster?
To answer them, let's turn to theory again.
First you need to understand that an electric motor moves the boat in displacement mode. The connection between the size of the boat and the speed of movement in displacement mode is almost unambiguously established through the Froude number.
We won’t give formulas, but for boats up to 7-8 meters long and with a displacement of up to 3000 tons, the maximum speed does not exceed 10 km/h.
We have compiled a table of the maximum speeds in displacement mode.
The choice of battery will ultimately be determined by price and frequency of use. A regular car battery can be “killed” in 5-10 trips to the water.
The traction battery will last several times longer in this operating mode.
Due to the fact that the cost of traction batteries is 2-4 times higher than starting batteries, but at the same time they last 5-10 times longer, it makes sense to spend money on them if you go out on the water more than 5-10 times a day. year.
What capacity does the battery need for the selected motor?
The question is directly related to the traction characteristics of an electric motor. Data on different motors and operating time of a 100 A*h battery are shown in the table below:
LBS | 10% power | 25% power | 50% power | 75% power | 100% power |
30 | 17.5 | 11.67 | 7 | 4.67 | 3.5 |
32 | 16.5 | 11 | 6.6 | 4.4 | 3.3 |
35 | 15 | 10 | 6 | 4 | 3 |
40 | 13 | 8.67 | 5.2 | 3.47 | 2.6 |
44 | 12.5 | 8.33 | 5 | 3.33 | 2.5 |
46 | 12.5 | 8.33 | 5 | 3.33 | 2.5 |
50 | 12 | 8 | 4.8 | 3.2 | 2.4 |
110 | 10.5 | 7 | 4.2 | 2.8 | 2.1 |
165 | 10.5 | 7 | 4.2 | 2.8 | 2.1 |
These data are approximate and, in most cases, depend on the design features of the electric motor.
And one last thing. How can we determine how low our battery is on the water?
The easiest option is to install a voltmeter.
The voltmeter readings will serve as an indirect indicator of the degree of battery discharge. For traction batteries, devices have been developed (voltmeter principle), which already have a scale calibrated in percentage of battery charge.
This option is the most preferable, since recalculating the voltage into residual capacity each time is a tedious process.
Devices of this type are available in two versions: portable or built into the dashboard. For small boats, it is preferable to use a portable option.
For boats that have a dashboard, it is naturally better to install it permanently in this panel. This is due to the fact that batteries for powering an electric motor are usually stored in the bilge (in lockers, under the deck). Access to them becomes limited.
That seems to be it. We chose a motor and a battery and ensured its charging and control.
Now - let's go! Happy sailing!