What is a Power Inverter and Why do I Need One?

Are you the owner of an RV, SUV, car, boat or other vehicle, and want to be able to watch TV, cook, or power a laptop onboard? If yes, you’ll be needing a power inverter. But what are they, and what do they do?

Read on to find out why you’ll need one to power your gadgets on the road…

What is a Power Inverter?

Basically, they are devices that turn your vehicle battery’s direct current (DC) into alternating current (AC) – the kind of electricity you have in outlets in your house, that are connected to the energy grid.

Having a power converter means you can plug in your appliances and devices, and power them like you would through an electricity outlet in a house.

In your car, you can get USB adaptors for your cigarette lighter so that you can charge your phone or plug in your satnav. But for larger gadgets and electronics with proper plugs, you’ll need an inverter.

Working of a Power Inverter

Like we said, they convert currents to a type safe for use in vehicles. Your vehicle’s battery voltage provides a current that powers its internal workings – you’ll need to know which voltage your vehicle’s battery uses to choose the correct inverter.

The current supplied by a battery sticks on one circuit, in one direction – where the name ‘direct current’ comes from.

However, to power your gadgets, you’ll need alternating current, as those electronics need more power to function than the DC can provide. They’re made to function with the high-voltage AC current supplied in homes.

Power inverters increase the DC voltage, change it to AC, then use it to power your devices. They amp up your battery’s voltage so you can play video games and use a kettle in your RV. Cool, huh?

Size Selection

These babies come in a variety of sizes – most commonly 1000, 3000 or 5000 watts.

It’s recommended that a 3000 watt inverter is the happy medium between inverter sizes and best choice to get. They’re not too small like the 1000, or too powerful and overcharged like the 5000. If you need a little extra boost, there are 3500 watt capacities available.

Find the best 3000 watt inverter for your vehicle by checking out the useful comparison guide by Solar Know How.

Modified or Pure Sine Wave Inverter?

Besides the sizing, there are two main types of inverter – the modified sine wave, and the pure sine wave.

So, what’s the difference, and which one will you need?

  • Modified Sine Wave: These tend to be cheaper, and less powerful. However, they’re good for most everyday electronics you will want to use, just not very large ones.
  • Pure Sine Wave: These are compatible with pretty much all electronics, gadgets, and appliances, and produce a powerful current most like the one supplied by the electric grid. These are the most common choice, because they’re more likely to be compatible with anything you need to plug in.

Power inverters are useful for charging on the road without having to cart around adaptors and large plugs

Other Features and Tips

  • Power inverters are especially useful if you are setting up a solar power system – they convert energy from the sun into electricity you can use to power your gadgets within your vehicle. This is renewable energy that isn’t a drain on your vehicle’s battery.
  • Power inverters aren’t just for vehicles – if you have a small cottage or outhouse, they’re very useful for setting up a small power source there.
  • Many (but not all) power inverters come with USB outlets, useful for charging on the road without having to cart around adaptors and large plugs. For ease of use, get one compatible with USB.
  • The best inverters have digital screens which show you how much energy has been consumed and information about battery voltage. It’s useful to know these things at a glance, so consider getting one that has a screen.
  • Modern inverters have been made to be extra-quiet, so you won’t be woken up by a noisy machine while trying to simultaneously get some sleep and charge your phone in your RV.

Biomethane – The Green Gas

Biomethane, also known as the green gas, is a well-known and well-proven source of clean energy, and is witnessing increasing demand worldwide, especially in European countries, as it is one of the most cost-effective and eco-friendly replacement for natural gas and diesel.

Advantages of Biomethane

The key advantage of biomethane is that it is less corrosive than biogas which makes it more flexible in its application than raw biogas. It can be injected directly into the existing natural gas grid leading to energy-efficient and cost-effective transport, besides allowing natural gas grid operators to persuade consumers to make a smooth transition to a renewable source of natural gas.

Biogas can be upgraded to biomethane and injected into the natural gas grid to substitute natural gas or can be compressed and fuelled via a pumping station at the place of production. Biomethane can be injected and distributed through the natural gas grid, after it has been compressed to the pipeline pressure.

The injected biomethane can be used at any ratio with natural gas as vehicle fuel. In many EU countries, the access to the gas grid is guaranteed for all biogas suppliers.

A major advantage of using natural gas grid for biomethane distribution is that the grid connects the production site of biomethane, which is usually in rural areas, with more densely populated areas. This enables biogas to reach new customers.

Storage of Biomethane

Biomethane can be converted either into liquefied biomethane (LBM) or compressed biomethane (CBM) in order to facilitate its long-term storage and transportation. LBM can be transported relatively easily and can be dispensed through LNG vehicles or CNG vehicles. Liquid biomethane is transported in the same manner as LNG, that is, via insulated tanker trucks designed for transportation of cryogenic liquids.

Biomethane can be stored as CBM to save space. The gas is stored in steel cylinders such as those typically used for storage of other commercial gases.

Applications of Biomethane

Biomethane can be used to generate electricity and heating from within smaller decentralized, or large centrally-located combined heat and power plants. It can be used by heating systems with a highly efficient fuel value, and employed as a regenerative power source in gas-powered vehicles.

Biomethane, as a transportation fuel, is most suitable for vehicles having engines that are based on natural gas (CNG or LNG). Once biogas is cleaned and upgraded to biomethane, it is virtually the same as natural gas.

Because biomethane has a lower energy density than NG, due to the high CO2 content, in some circumstances, changes to natural gas-based vehicle’s fuel injection system are required to use the biomethane effectively.

A Glance at Biogas Storage Systems

Selection of an appropriate biogas storage system makes a significant contribution to the efficiency and safety of a biogas plant. There are two basic reasons for storing biogas: storage for later on-site usage and storage before and/or after transportation to off-site distribution points or systems. A biogas storage system also compensates fluctuations in the production and consumption of biogas as well as temperature-related changes in volume.

There are two broad categories of biogas storage systems: Internal Biogas Storage Tanks are integrated into the anaerobic digester while External Biogas Holders are separated from the digester forming autonomous components of a biogas plant. The simplest and least expensive storage systems for on-site applications and intermediate storage of biogas are low-pressure systems. The energy, safety, and scrubbing requirements of medium- and high-pressure storage systems make them costly and high-maintenance options for non-commercial use. Such extra costs can be best justified for biomethane or bio-CNG, which has a higher heat content and is therefore a more valuable fuel than biogas.

Low-Pressure Storage

Floating biogas holders on the digester form a low-pressure storage option for biogas systems. These systems typically operate at pressures below 2 psi. Floating gas holders can be made of steel, fiberglass, or a flexible fabric. A separate tank may be used with a floating gas holder for the storage of the digestate and also storage of the raw biogas. A major advantage of a digester with an integral gas storage component is the reduced capital cost of the system.

The least expensive and most trouble-free gas holder is the flexible inflatable fabric top, as it does not react with the H2S in the biogas and is integral to the digester. These types of covers are often used with plug-flow and complete-mix digesters. Flexible membrane materials commonly used for these gas holders include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low density polyethylene (LLDPE), and chlorosulfonated polyethylene covered polyester. Thicknesses for cover materials typically vary from 0.5 to 2.5 millimeters.

Medium-Pressure Storage

Biogas can also be stored at medium pressure between 2 and 200 psi. To prevent corrosion of the tank components and to ensure safe operation, the biogas must first be cleaned by removing H2S. Next, the cleaned biogas must be slightly compressed prior to storage in tanks.

High-Pressure Storage

The typical composition of raw biogas does not meet the minimum CNG fuel specifications. In particular, the CO2 and sulfur content in raw biogas is too high for it to be used as vehicle fuel without additional processing. Biogas that has been upgraded to biomethane by removing the H2S, moisture, and CO2 can be used as a vehicular fuel. Biomethane is less corrosive than biogas, apart from being more valuable as a fuel. Since production of such fuel typically exceeds immediate on-site demand, the biomethane must be stored for future use, usually either as compressed biomethane (CBM) or liquefied biomethane (LBM).

Two of the main advantages of LBM are that it can be transported relatively easily and it can be dispensed to either LNG vehicles or CNG vehicles. Liquid biomethane is transported in the same manner as LNG, that is, via insulated tanker trucks designed for transportation of cryogenic liquids.

Biomethane can be stored as CBM to save space. The gas is stored in steel cylinders such as those typically used for storage of other commercial gases. Storage facilities must be adequately fitted with safety devices such as rupture disks and pressure relief valves. The cost of compressing gas to high pressures between 2,000 and 5,000 psi is much greater than the cost of compressing gas for medium-pressure storage. Because of these high costs, the biogas is typically upgraded to biomethane prior to compression.