Power Consumption Calculator In Boat
An increasingly popular question we hear at Boat Shows is 'What size solar panel do I need to run the refrigeration on my boat?' Of course, this begs the question 'What is your refrigeration's current draw?' Which in itself may not have a set answer.The current consumption of any refrigeration system is meaningless unless all the conditions are specified, i.e.
Box temperature, ambient temperature, water temperature, compressor speed, voltage, etc. The manufacturer's figures are simply average numbers; some manufacturers, like Frigoboat, attempt to give a true average figure, while others use their figures more as a marketing tool.Making use of variable compressor speed, as Frigoboat does with the and speed controls, and others do with the Danfoss/Secop AEO control module, brings even higher efficiency and lower overall power consumption in air- and keel-cooled systems, but is counter-productive in a pumped-water system. This is because the pump adds 25% to 35% extra current draw, and so it is best to run the compressor at full speed and get the job done as quickly as possible. The most efficient system is one using the; no pump, no fan, and variable compressor speed can be used to gain even higher efficiency.Daily consumption is measured in amp/hours per day, and you can get an idea of what to expect by using a watts meter, like Watts Up, on your refrigerator leads. These meters can tell you how many amp/hours per day a device is using, and it's best to use it over several days to get a daily average. The running consumption will vary dependent on conditions, as will the on/off cycle time, so you will need to be able to come up with an average daily amp/hr draw.As a general rule of thumb, a solar panel with SunPower® cells will give approximately 1/3 of its rated wattage as a daily yield in amp/hrs. A panel with regular monocrystalline cells will produce about 1/4 of its wattage as daily amp/hrs, and a polycrystalline panel produces around 1/5 of its wattage rating in amp/hrs per day.Let's take an example:A Frigoboat Keel Cooler system using 25 amp/hrs a day (a typical report from cruisers in The Caribbean with a 6 cu ft box).
If the boat has 'normal' monocrystalline solar panels, i.e. Not the high efficiency ones with cells, they will produce around 1/4 of the rated watts output in amp/hours per day; so with these types of panels the boat will need at least 100 watts (25 amp/hours x 4 = 100) of solar just to keep the fridge and freezer running.
If the panels are made with SunPower® cells, then count on needing only 75 watts (25 amp/hours x 3 = 75) of these higher efficiency rated panels to do same job. That's assuming there is a battery bank large enough to hold the necessary reserve needed should the sun not shine for a day or two.All of this is explained further in our guide.
Frequently Asked Questions About Electric Boat MotorsRANGEWhat kind of range should I expect from an electric boat motor?For a boat using an electric motor, consider the battery as your “fuel tank.” Therefore, the more battery power available the more “fuel” available. Range will ultimately depend heavily on the type of cruising you plan on doing and how many ‘battery banks’ you have available. Wind, water current and water conditions also affect your time on the water.A general range optimization strategy is to find the “sweet spot” where your speed and amp draw will get you the most range. Generally this means drawing back on your knot speed to approximately 50-60% of your hull speed and using around 20-30% of your available amp draw.Below is a theoretical range graph one might expect to see powering with an electric sailboat in smooth conditions.As you can see, the amp draw to speed is not linear, however, there is a “sweet spot” in which the range is optimized for approximately 22 nautical miles while maintaining an approximate speed of 4.2 knots and at the same time only drawing 23% of the available amp hours. (based on a 200Ah system)By sacrificing a few knots, there is a 145% increase in range.This graph is for illustrative purposes only and represents a theoretical example. Water conditions and individual boat dynamics will compute different findings.POWERWhat kind of battery is best for my electric boat motor?
AGM or Lithium?At this point due to cost we recommend using AGM (Absorbed Glass Mat ) batteries over lithium. These batteries create voltage using the time tested lead acid technology however they use much less battery acid than a traditional lead acid battery. What factors decide which system voltage will be best for an electric boat motor?Currently we offer 48V and 72V systems. Ultimately we look at this in terms of wattage, the higher the wattage demand the higher the voltage required. If you want more power for your electric boat, you will require a more powerful electric motor. What kind of power characteristics can I expect from an electric boat motor?An internal combustion engine idles at 700-800 rpm – and must rotate at 1500-2000 rpm to make enough torque to drive the boat forward.An electric propulsion system does not idle and can provide full torque at any speed if it runsat full current.
This gives you very high torque available for acceleration.The main power consumption is used to accelerate the boat up to the desiredspeed. Thereafter, the power consumption drops significantly when using anelectric motor to cruise. How do I regulate RPMs on an electric boat motor?The RPMs on the motor are regulated by adjusting the voltage with the motorcontroller. The motor controller chops the voltage from the batteries into smallpulses. The longer the pulse sent to the motor, the more power and RPM the motor outputs.
Pc Power Consumption Calculator
This instant use of available power makes the system extremely efficient. Why is there reduction gearing on an electric boat motor?There are 3 great reasons for using gear reduction. It’s easier on the motor to spin the prop which means there is less current draw from your batteries.
Power Consumption Calculator In Boat Rentals
If by unfortunate chance you hit your prop, the pulley and belt will absorb the impact vibration from the propshaft. If the propshaft is directly linked to your electric motor the chance of damage is significantly more should an impact occur. Gear reduction produces Torque. The torque produced by the output is inversely proportional to the amount of gear reduction. In short, if you have a 2:1 gear ratio then the prop speed turns 1/2 as fast but has twice the torque!