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Generator Buying Guide: Everything You Need to Know

two men using a petrol frame mounted generator

Whether you’re a home/business owner preparing for potential power cuts, or need off-grid power for your devices while camping, having a generator on hand is essential.

This comprehensive guide is designed to equip you with all the information necessary to select the ideal generator for you, covering the different types of generators, how they work and how to choose the right size device for your needs.

What Is a Generator and How Does It Work?

In short, generators are valuable appliances that supply electrical power at times when the main supply is unavailable, for example, during a power outage, to prevent interruption of daily activities in the home or disruption of business operations. 

Generators are available in a variety of sizes and types, ranging from small portable units suitable for camping or construction sites to large standby generators designed for home or business use.

Most transportable generators consist of an internal combustion engine, an alternator and a fuel tank.

  • Petrol or diesel generators are filled with liquid fuels, which are then used to generate power. The internal combustion engine housed within these generators drives an onboard alternator, transforming mechanical energy into electrical energy.
  • LPG generators connect to a propane tank and work in a similar way to petrol generators. Once the tank is empty, you’ll need to exchange it for a replenished one.
  • Battery generators use battery packs to store electricity. They are smaller and more portable than alternatives that use a fuel tank, but are only really useful if you have a low power demand. They can often be charged with solar panels or a carport (useful at festivals or camping).

Petrol frame mounted generator with a cable running from the generator to power tools.

The Different Types of Generators

Generators come in a variety of different types, each designed for specific applications and power requirements.

The main types of generators include:

1. Home Standby Generators

A standby generator is a heavy-duty device that is hardwired into your home or business, designed to provide backup power during an electrical outage.

It is connected via a transfer switch and automatically turns on when it detects a power outage. It will then turn off when it senses power has been restored.

They are capable of providing enough electricity to power essential systems and appliances, including lights, heating and cooling systems and refrigerators. Larger generators can even provide enough power to run the entire building.

2. Portable Generators

Portable generators are compact and movable power units designed for temporary or mobile use. They typically run on petrol and are less expensive than standby generators.

Due to their small size and portability, they are ideal for camping, hiking, or RVing trips when you only need to power a few devices.

As they are designed to be easily transported from one location to another, they often come with built-in handles or wheels for convenient movement.

Petrol v Diesel Generators

Petrol and diesel generators are two common types of portable generators that operate using different fuel sources.

Some of the main differences include:

  • Fuel source – As it says in the name, petrol generators run on gasoline, which is readily available at most petrol stations. Diesel generators run on diesel fuel, which is often more energy-dense and commonly used in heavy machinery and vehicles.
  • Cost – Due to their larger size and greater power output, the initial cost of diesel generators are typically higher than petrol. Also, in the UK, diesel fuel typically costs more than petrol, so the cost to purchase and run diesel generators is somewhat higher.
  • Efficiency – Diesel generators are often more fuel-efficient than petrol generators as they have higher compression ratios and thermodynamic efficiency. Petrol generators may consume more fuel than diesel generators, especially under heavy loads, leading to shorter runtimes between refuelling.

For more expert advice about petrol & diesel generators, get in touch with our friendly team on 01639 849847 or email [email protected].

Petrol frame mounted generator with a cable running from the generator to power tools.

3. Inverter Generators

An inverter generator is a type of portable generator that adapts to the power demand placed on it by throttling up and down. 

Inverter generators are designed to operate quietly, making them suitable for use in noise-sensitive environments such as campsites, residential neighbourhoods, or outdoor events. 

They are also typically more lightweight compared to traditional generators of similar power output, making them much easier to transport and store, ideal for camping trips, or other outdoor activities where space is limited.

4. Solar Generators

A solar generator operates like a large battery that harnesses energy from sunlight to generate electricity.

Unlike traditional generators that rely on fossil fuels or other energy sources, solar generators utilise photovoltaic (PV) panels to convert sunlight directly into electricity.

Solar generators are ideal for use in a short time period and for powering a small number of devices at once. They are also often lightweight and compact, making them easy to transport and set up in remote locations.

Since they don’t have an engine, solar generators run quietly, which could be a benefit for those worries about noise level.

Choosing the Right Size Generator

Choosing the right size generator is absolutely crucial for ensuring that your essential appliances and devices remain powered.

To calculate the appropriate size of generator needed, you should first understand the factors that influence generator size. These include:

  • Wattage (W) and Kilowattage (kW) – Generators are rated by their power output, which is measured in watts (the amount of electrical power produced) or kilowatts (equivalent to 1,000 watts). The higher the wattage of a generator, the more items it can power at once
  • Starting (Surge) Wattage vs. Running (Continuous) Wattage – Running watts represents the amount of continuous watts needed to keep items running, whereas starting watts refers to the extra watts a generator must provide to turn on an appliance.
  • Load Size – Load size refers to the appliances and devices that you need to power during an outage. Are you looking for a device that can keep a couple of smartphones charged during a power cut, or do you need to power something larger such as a fridge for medical equipment?

a man holding an inverter suitcase generator and pulling the pull cord to start the generator

To find the right size generator, make a note of all the appliances and devices you’ll need to power and their approximate starting and running wattage. This total represents the minimum wattage capacity your generator should provide to meet your needs. 

If you intend to supply electricity to your home, you should evaluate the power needs of the distribution board, typically operating at 230V with a 100 Amp capacity. However, if you’re planning to power specific household items, such as the lights, fridge, kettle and WiFi, you can approximate the power consumption per device. To find the individual wattages per item, check the equipment itself, in the user manual, on a manufacturer’s website, or by contacting the manufacturer.

If you’re just looking to charge your smartphone or tablet on the move, you’d be better off with a portable power bank. Check out our range of quality power banks here. 

To learn more about choosing the ideal generator size, check out our recent blog. 

Looking For a Quality Generator?

At Generators Direct, we offer a range of generators, power stations and power banks for your specific needs. All of our products are manufactured, tested and certified to industry standards, and come with a price promise – you won’t find prices cheaper anywhere on the web, but if you do, we’ll match them. In addition to this, all orders come with free mainland UK shipping and after sales support from our experts.

If you require additional advice or have a question for our team, don’t hesitate to get in contact with us using this form or via phone at +441639849847.

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