Generator Selection & Load Calculations For Ham Radio DX-Pedition

 

 

Generators are useful in Ham Radio Dxpedition where is there NO power source available, especially in remote places they provide a power source for the activities and the team, and the fuel is cheap because they use a diesel fuel type; many generators support dual fuel tanks and extended tank option, which provides users with more options to select from depending upon their needs and usage. They may also be portable with different sizes depending on their output power. However, there are standby generators available in the market which have their own benefits. A general idea is the more the power wattage, the heavier the generator will be. There are many other factors that come into play for generator selection, so an educated choice needs to be made for selection.

 

Selection Choice & Load Calculation:

For the selection, first look into the wattage use. To calculate the load in use, i.e., for every appliance, add the wattage, which you can find on the device panel. Here a caution needs to be taken since there are two categories for power, one is running power, and the other is surge power. Running power is the normal wattage use while an appliance is running, and the surge power is the peak power when a device is started. You may see on a device the power rating as 1000-1300 Watts. Here the 1000 is the running power, and it may go as high as 1300 when the appliance is powered up.

Here Let’s Discuss An Example Of  Low Load Calculation For Dxpedition Equipment:

·         Radio (x3) 100-120 Watts

·         Power Supply (x3) 300- 380 Watts

·         LED Lights  (x1) 220-250 Watts

·         Amplifier (x2) 150-180 Watts

Now Let Us Calculate The Total Power Load For The Equipment We Have.

 

Power Load =

{Sum Of Product Of Power Load By Each Type Of Device} X 1.5

PL = {(3x100) + (3x300) + (1x220) + (2x150)} X 1.5 = 1720 X 1.5 = 2580 Watts

 

 The 1.5 factor is the formula is recommended to cater to the surge power, and also, it's always a wise choice to add a few extra hundred watts of power to your load calculation to avoid any unforeseen issues.

The number of hours a generator can run is dependent upon the power rating calculated at half capacity (50%). Say a generator is rated to run for 12 hours and has a power rating of 5000 Watts, it will run for 12 hours at a constant power output of 2500 Watts.

Output At Given Run Time = Power Rating X Half Load Capacity =

5000 X 0.5 = 2500 Watts

If you are not sure about the watts and have voltage and current usage, the following method is adopted to get the required wattage.

Power = Volts x Current x Power Factor

Power = 220 x 15 x 0.8 = 2.64 kW

Now, This Kw Can Be Converted To Apparent Power Kva As:

Apparent Power kVA = Real Power kW / Power Factor = 2.64 kW / 0.8 = 3.3kVA

To Calculate An Approximation For The Fuel Consumption, Use The Following Steps:

1.      Get Rating From Kva To Kw.

2.      Convert Kw To Kwh.

3.      Convert Kwh ( At 50% Capacity ) To Liters Or How Many Liters Does It Use For 1 Hour.

4.      Convert Liters/Hour To Gallon Per Hour (1 Lt/H = 0.2642 Gal/H)

3.3kVA generator has a rating of 0.05 liters per kWh usage, then we have as per the above steps:

1.      3.3 kVA x 0.8 = 2.64 kW

2.      2.64 kW x 1 hour = 2.64kWh ( 50% Capacity Is 1.32 Kwh )

3.      1.32 kWh x 0.05 = 0.07 liters/hour

4.      0.07 lt/h <=> 0.02 gal/h

This is an approximated method; however, the larger the generator is operating a lot more efficiency it will produce and less gasoline consumption per second.

Figure 1 Approximated Fuel Consumption at Different Load Levels From

https://fwpower.co.uk/knowledge-centre/diesel-generator-fuel-consumption-chart-in-litres/

 

Portable VS Standby:

Now that we have the load calculation, the next step would be to look for the right size and fuel consumption type. These two features usually come in together. There are now two options to go for. If you need the portability and would like to move around the generator to other locations, it’s ideal to go for the portable ones. Portable generators also come in a handheld type where they can be carried around, but the power wattage is usually less than 500 Watts and weigh around 50-100 pounds. For heavy usage, they are ones with wheels and cat-like structure. These support the higher usage and can easily be dragged to other places. An additional feature is that there is a power switch, and it needs to be started whenever you run out of power.

An alternative to portable generators is standby generators. They are mostly used where there are more frequent and unexpected power outages. These are usually used for wattage usage greater than 2000 Watts and cost a bit more. The installation may also cost additional charges and would require an expert to properly install the entire setup. The good thing about these generators is that they are operated entirely on gasoline or on propane, so they don’t require as much maintenance as compared to the portable ones. The auto-start feature makes it reliable for situations where there is an uninterrupted need for power.

Accessories For Precaution:

No matter what type of generator you purchase, there are some accessories that you must purchase or look into brands that offer those with the generator. Fuel gauge and fuel stabilizer are necessary for proper fueling and maintenance. A battery for push start is recommended to avoid any physical labor. A noise suppressor muffler is recommended since the generators make a lot of noise, and it increases as the power rating goes higher.