How Do You Calculate What Size Generator Do You Need?

How Do You Calculate What Size Generator Do You Need?

A power generator is an essential part of any business that needs to be up and running around the clock. The generator should be able to power all of the equipment needed to keep your business open regardless of the weather conditions or natural disasters that might strike. That means you need a commercial diesel generator that can provide enough power for your entire building.

Why Does Proper Generator Sizing Matter in the place first?

An improperly sized diesel generator won’t just leave you with a bill for a piece of equipment you can’t use. It will cause damage to other electrical appliances in your building for which it was not intended. Using an undersized generator for your household or business can result in having to run it longer than needed. That means it will only partially power your electrical equipment, thus causing them to run at higher speeds than usual and shortening their working life. In addition, it could consume more fuel, increase your overall costs, and cause safety hazards like overheating, leading to fire accidents if left unattended.

On the other hand, using a generator that is too large may seem like a good idea at first, but you might find out later that it was a poor choice. This article outlines some valuable factors to consider when deciding what size diesel generator you need.

Evaluate Your Power Requirements

Deciding on the size of a commercial diesel generator is not as simple as choosing one based on how much power you reckon you’ll need. When determining the right size and type of generator for your business needs, several factors must be considered. Based on your business type, the power requirement may vary. So, start by making a list of absolutely essential items that you need to power, including appliances and lights. Once you have the basics covered, add items like TVs and microwaves that aren’t necessary for life safety but would be convenient after a power outage. In addition, ask your diesel generator manufacturer about the machine’s run time and whether they offer a warranty or not.

Different Types of Power Measurement Methods

You can determine what size of commercial generator you need through different methods, such as calculating your power usage, considering the power factor, assessing load capacity, etc.

Power Usage Calculation

To calculate the power that your commercial appliances need, you have to multiply their voltage with amps. After that, you have to multiply it again with the number of hours they will be running. You should do this for all the appliances you want to be powered by the generator. Using a clamp-on ammeter is the most accurate method of getting the real-time measurement and determining how much load you will place on a generator. The best way to use this method is with an appliance that has a motor (such as a refrigerator) because motors fluctuate in their power draw as they cycle on and off. By connecting an ammeter to the appliance and running it for about 15 minutes, you can accurately measure its average load on your generator. This same course of action can be used for other appliances by adding more meters until all appliances needing power are measured. Once the total wattage is calculated, add 25% to account for any fluctuations.

For example:

A refrigerator that runs at 120 V and 2.5 A for 24 hours a day will require 120 x 2.5 x 24 = 7,200 W or 7.2 KW per day.

Evaluate Load Capacity Based on Your Power Consumption History

This method involves looking through your bills from previous months and identifying the highest peak usage for each month. Once you identify the highest consumption point, add 25% for reserve capacity to it.

Calculate Full Load Capacity Based on Motor Usages

If you have extensive motor use or need to add up multiple appliances, it’s easier to calculate the total watts needed by adding up the full load capacity of each item.

Step 1: List the electrical items that run on motors, and you want to power during an outage in order of importance. That may include well pumps, refrigerators, and freezers.

Step 2: Determine how many watts it takes to start the motor(s) on the items from step 1. (Essentially, the starting wattage is 3-5 times the running wattage for most motors.)

Step 3: Add the watts for each item, starting from the largest motor to a small motor and non-motor loads.

Step 4: From there, you will want to divide your total by 1000 to get your kilowatt (kW) requirement and then add 25% of that total value to arrive at your total wattage needs.

Calculate Running & Starting Watts

There are watts used when an appliance or tool is running (running watts). And then, there are watts used when the appliance or tool is starting up (starting watts). Running watts are the essential requirement needed for an appliance to operate consistently. Starting watts are required to get the appliance up and running. The difference between them can be significant.

Don’t just add up the running wattage numbers you see on your appliances because startup or surge watts are often three times higher than running watts. In addition to the standard wattage requirement of an appliance or tool, there is also an initial startup requirement. This surge lasts only a second or two, but it’s essential to include this in your total wattage calculation.

Multiply the running watts by three if you have items with electric motors. Electric motors have higher startup requirements than running requirements. Multiply the running watts by 1.5 if you have items with computers chips (think TVs and microwaves).

Do you need help determining what diesel generator would be the right fit for your specific business needs? Skyline Power Solutions can help. Our power specialists will take into account all aspects and help you choose the right diesel generator. Contact us at 9212552666.