Finding a reliable source of traction for small swimming aids often leads enthusiasts to the decision to purchase a new one. 12-volt electric motorIt's the best choice for owners of PVC inflatable boats, small boats and kayaks, where not only efficiency of movement is important, but also noiselessness and environmental friendliness. Unlike gasoline counterparts, electric units do not require complex maintenance, do not emit exhaust fumes and allow fishermen to sneak up on the prey without the risk of spooking it with noise.
But the market is oversupplied, and it's getting harder to buy a really high-quality device with the stated specifications. Many models that are marketed as "powerful" are actually weak toys that can't overcome the current or the wind. In this article, we'll break down the technicalities, help you determine the thrust you need for your vessel, and give you a hint of what you should look for so that you don't become a disappointment.
You'll find out why. voltage The power system is a critical parameter and how to choose the right battery for long-term battery life. We will look at the design features of the lower unit, the types of screws and control systems that directly affect the maneuverability and speed of your vessel on the water.
Selection criteria: traction, power and design
The first thing that a customer encounters is the confusion between horsepower and pounds of traction. thrustThe wattage is secondary and depends on the efficiency of a particular engine. To buy a really powerful unit, you need to understand that for a boat with a length of 3-4 meters with one passenger, the minimum thrust is 30-40 lbs (about 14-18 kg).
And the design of the lower unit is also very important, and there are two main types: rigid or telescopic shaft, and flexible shaft. telescopic They allow you to adjust the depth of the propeller, which is critical for shallow waters or overgrown bodies of water. A rigid shaft is usually more reliable and durable, but requires accurate selection for the height of the transompenes.
Pay attention to the material of the body of the lower unit. Aluminum alloys with anti-corrosion coating are preferable to plastic, because they are better able to withstand impacts on stones or drowners. However, modern composite materials also show high strength at less weight.
The cooling system is an important aspect. Most modern models use water cooling, which increases their efficiency and allows them to operate at high speeds for long periods without overheating. Dry motors often have a time limit for continuous operation at full power.
Calculating the necessary thrust for your vessel
A precise calculation is required before ordering. Buying an engine by eye can lead to a situation where the boat barely overcomes the resistance of the water. There is a rule of thumb: for every 500 kg of total weight (boat + motor + battery + equipment + people), approximately 40-50 kg of thrust is required for a comfortable ride against moderate wind.
Consider the approximate table of correspondence of the length of the boat and the required thrust of the electric motor:
| Boat length (m) | Max. load (kg) | Recommended traction (lbs) | Recommended traction (kg) |
|---|---|---|---|
| 3.0 | 400 | 30 - 34 | 13 - 15 |
| 3.0 - 3.6 | 400 - 600 | 40 - 45 | 18 - 20 |
| 3.6 - 4.2 | 600 - 800 | 50 - 55 | 22 - 25 |
| 4.2 - 4.8 | 800 - 1000 | 60 - 70 | 27 - 32 |
Consider that the shape of the hull also affects the drag: flat-bottomed boats require more thrust to get on plane or just fast movement than keel vessels. If you plan to go against the current or often get into strong headwinds, take a model with a power reserve of 20-30%.
The effect of wind on speed
With a 5-7 m/s headwind, the speed of the boat can drop by 40-50% even if the engine is running at full power, which is why the thrust reserve is critical for safety.
Don't forget the weight of the battery itself, which is part of the total load.LiFePO4) the batteries are significantly lighter than lead-acid counterparts at the same capacity, thus saving weight for a more powerful motor.
Types of management and functional features
The modern high-power 12 volt motor is a sophisticated electronics device that can be controlled through a ramper, pedals or remote control. tiller control is classic and the most reliable, especially in vibration and splash conditions. Pedals are more often used on trolling boats, leaving the angler's hands free.
- 🎛️ Step-shifting It's usually 3-5 speeds forward and 2-3 speeds backward, a simple and reliable system where each speed corresponds to a specific voltage on the windings.
- 🌊 Incremental adjustment It's a smooth change of speed, with a potentiometer or electronics, and it allows you to precisely match the speed for trolling.
- 📡 GPS anchor systems Top models are able to keep the boat at a point in coordinates, automatically thrustering against the wind and current.
Special attention should be paid to the charge indication system, built-in voltmeters or LED scales allow you to monitor the remaining energy in real time, which prevents the situation when the motor stalls in the middle of the reservoir due to deep battery discharge.
Use a separate voltmeter with a remote probe to monitor the voltage at the battery terminals under load. Integrated indicators in the motor can show data with an error due to the length of the wires.
Function transporting-place It allows you to lock the deadwater horizontally, lifting the screw above the water, which is convenient when passing shallow areas or mooring, to avoid fouling the screw with algae.
Battery base: power powerful motor
Buying a powerful motor is only half the battle. The other half is the right battery pack. Standard car starter batteries are not suitable for long-term electric motors. They are designed for short-term high-current returns and quickly degrade in cyclic discharge.
You need a Deep Cycle, which comes in a number of different types:
- 🔋 GEL and AGM - sealed lead-acid batteries, maintenance-free, safe, but with limited cycle life (300-500 full discharges).
- ⚡ LiFePO4 Lithium-iron-phosphate batteries are 3 times lighter than lead batteries, have a life of 2000+ cycles and give full capacity even at high discharge currents.
- 💧 Liquid electrolyte Classic traction batteries are cheap, but require maintenance, ventilation and installation strictly vertically.
⚠️ Attention: With a powerful motor (from 50 lbs) at 12 volts, currents can reach 40-50 Amps. Make sure that the wire cross-section from the battery to the motor is at least 6 mm2 (copper), and the contacts are reliably compressed. Thin wires will lead to a voltage drop and overheating.
Battery capacity directly affects the time of autonomous navigation. For a medium-powered motor (30-40 lbs), the best choice would be a 100-Ah battery. This would provide about 4-6 hours of active movement in mixed mode. If you plan to go many hours, it makes sense to consider a dual-power system or a 24-volt switch.
☑️ Checking before getting on the water
Installation and preparation for operation
Installing an electric motor on a transom requires a few rules. Most models are attached with rods, which must have rubber pads to protect the hull of the boat, and it is important to set the motor strictly in the center of the transom and perpendicular to the keel to avoid the boat moving away.
The depth of the propeller is critical. The optimal position is when the propeller is 15-25 cm below the water level. If you lift the engine higher, cavitation and suffocation will begin, which will lead to loss of traction and noise. If you lower it too deep, water resistance will increase.
Procedure for installation:1. Relax the clamps of the rods.
Set the motor on the transom.
3. Tighten the strubcines with a force sufficient for fixation, but without deformation of the transom.
4. Put the deadwater in the water.
5. fix the safety falter (in case of falling overboard engine).
Inflatable boats have special transom boards that distribute the load from the engine over a large area of cylinders, and using a powerful electric motor without such a board can lead to deformation of the aft part of the boat.
Properly installed motor and depth of propeller immersion can increase the efficiency of the stroke up to 15-20% without additional energy consumption.
Maintenance and care
Electric motors don't require changing oil or filters, but regular maintenance is essential for the long life of the device. After each release, especially in salt water, the diewater must be washed with fresh water. Salt and sand are the main enemies of bearings and glands.
Periodically check the condition of the screw. The presence of chips, burrs or coiled algae disrupts the balance and creates vibration that is transmitted to the shaft and can damage the ossils. If damage is detected, the screw should be replaced or repaired.
- 🛠️ Lubricant Once a season, it is recommended to lubricate the moving parts of the lifting and turning mechanism with special marine lubricants.
- 🔌 Contacts - Check the oxidation terminals. Use the spray protection for electrical contacts.
- 🌡️ Storage Keep the motor in a dry room at plus temperature, and in winter the battery should be kept on a charger with a storage mode.
⚠️ Attention: Never turn the motor on outside the water, even for a short time. Lack of water cooling (if it is designed) and operation of the screw in the air can lead to instant overheating and breakage.
Replacing the osteoils in a timely manner (usually every 2-3 seasons of active use) will prevent water from entering the lower unit and corrosion of the electrical part, an inexpensive procedure that saves the engine from major repairs.
Frequently Asked Questions (FAQ)
Can a 12B electric motor be used in seawater?
Yes, most modern motors are corrosion-proof, but after use in salt water, they must be thoroughly washed with fresh water. Saltwater-labeled models have enhanced protection, but prevention is essential for everyone.
What is the real speed of an electric boat?
Speed depends on many factors, but on average, a single-person PVC boat with a 30-40 lbs engine develops 5-7 km / h at top speed. At trolling speeds (1-2 km / h), battery life lasts 6-8 hours.
Do I need to register a boat with an electric motor?
According to the current rules (in Russia), registration in GIMS is not required if the power of the electric motor does not exceed 250 kgf (about 3.4 hp or about 15-16 kW), and the weight of the boat without the engine is less than 200 kg. Most 12-volt engines meet these standards.
What to do if the engine loses power?
First, check the battery's charge under load. If the battery is fine, check the screw for coiled algae or fishing line, and the problem may be oxidized contacts or wear of engine brushes.
Can I charge the LiFePO4 battery with a conventional charger?
No, lithium batteries require special chargers with the appropriate charge algorithm (CC/CV) and voltages. Charging with a lead charger can damage the BMS board of the lithium battery.