Power Inverter Buyers Guide

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If you often go camping, caravanning or enjoy outdoor activities, then you’ll understand the importance of having a power inverter.

And if you’re new to participating in outdoor activities such as caravanning, then welcome to the world of power inverters, the handy machine that will help you have your essential electrical goods and home comforts whilst your away.

What is a Power Inverter?

A power inverter enables you to use Household (230V) electrical devices such as a microwave, cooker, lights, computer, television, kitchen appliances, tools and so on, by converting DC power from a battery to conventional AC power, which is what is needed to be able to run all 230V electrical devices. By having an inverter this enables you to have your own portable power supply, wherever you may be.

DC power is stored in a battery and AC power is delivered in homes via your 3 pin socket.. They both possess different types of current and voltage in the use of transmitting electricity.

AC transmits electricity via a wave formation, usually because it has come from a power source that has had to travel far. Whereas DC transmits electricity in a straight line and is found typically in batteries.

To get power, you simply connect your inverter to your battery and plug in your appliances to the inverter for them to work.

Now obviously, you are going to need to recharge your battery once it has been discharged by the inverter. To recharge the battery you can either do so by connecting a suitable battery charger, using renewable energy sources such as solar or wind or by the in-vehicle charging system.

How long can I run an inverter for?

How long an inverter will be able to power your appliances depends on the size of the battery it is running from and the load. The inverter rating is the maximum power that can be supplied to the appliances. How long it runs is a factor of the appliance load and battery size. E.g you have a 50w TV. It's running on a 300W inverter. If you have a 500 watt-hour battery then it would run for 10 hours (500/50).

What many people do to increase the inverters operating time is to create a battery bank, where several batteries are connected together, so more power can be distributed over a longer period of time.

What size inverter should I buy?

The size of the inverter you buy depends on how much power you’re going to require from it to power all of your electrical devices.

First, you’ll need to work out the total amount of watts you’ll be consuming when all appliances are on.

First, you need to think about the size of the inverter you are buying. As both inverter types are available in multiple sizes, you’ll need to purchase an inverter that will cover your total energy consumption (this is known as watt-hour. (Buying an inverter that can sustain the power usage you are going to use).

For example, if you are going to run a radio (10 watts), computer (300 watts) and lights that have a rating of up to 120 watts then your total watts being used is 430. Therefore you’d need an inverter that has a minimum of 500 watts.

If you’re going to need for example 2300 watts then you’re going to need an inverter that can power 3000 watts.

Generally, inverters are available in sizes from 300W - 8000W

Should I get a bigger power inverter no matter how much I use?

Well, you could, but if you’re only going to use a small amount of power say 400W and you have a 3000-watt inverter, you aren’t going to be using the inverter efficiently.

You should always try to use an inverter that is slightly more than the number of watts you're going to be using, to get the right amount of power for your needs.

By going for a reasonably higher rated inverter you will help prolong the life of your inverter and it won’t be working at maximum capacity, for the whole duration you use it putting less stress on internal components

However, it is always better to buy a higher rated inverter than required than something too small.

Different types of inverters

Now that you’ve been introduced into the world of inverters, it’s time to tackle the different inverter types and what they actually do. This will help you select the correct inverter type for your application

There are two main categories of inverters - Pure Sinewave and Modified Sinewave.

What is a Pure Sine Wave Inverter?

A Pure Sinewave Inverter provides high-quality electricity that is either better than or equal to the electricity you’d find in your home from the utility company.

If you are wanting to power appliances such as medical equipment or expensive electrical appliances we’d suggest plugging these into a Pure Sinewave Inverter to ensure they don’t get damaged and work to the best of their ability, something that may be affected when used with a Modified Sinewave Inverter.

The wave produced by a pure sinewave inverter is a smooth clean sinusoidal wave that is capable of powering any appliance within the inverter rating.

All loads run quieter, cooler and more efficient on pure sinewave, we also recommend pure sinewave inverters for inductive loads (appliances with motors/compressors).

If an inverter is to be used on a daily basis a pure sinewave inverter is recommended as a more reliable solution.

What is a Modified Sine Wave Inverter?

A Modified Sine Wave Inverter provides a lower form of electricity, so not as Clean as the power you’d find within a home.

Modified sinewave inverters produce a square sinewave which is suitable for 80% of appliances - TVs, standard computers/laptops, fridges, lighting (NOT fluorescent), vacuums, microwaves, hairdryers, 18V tool charging etc are all suitable loads.

Modified Sine Wave Inverters are safe to power most electrical equipment and are a good option when using them for leisure/occasional use.

In addition to the above - Example of loads that are not compatible - electric toothbrushes, medical equipment, some audio equipment, air compressors, welders, High spec computers, Digital interfaces (clocks, radios, panels etc), laser printers/photocopiers, some battery chargers.

Because the total harmonic distortion (THD) is higher in modified sinewave inverters, motors will run hotter (less efficiently, consuming up to 30% more energy than with pure sine wave inverters), and likely not last as long. Additionally, a modified sinewave inverter will often cause a “buzz” to be heard from audio devices and sometimes other appliances.

Although the Pure Sine Wave Inverter will always be the preferred inverter to use, it is, however, more expensive thanks to its complex design.

This doesn’t necessarily mean to say that you have to purchase this kind of inverter, if you’re using basic appliances then a Modified Sine Wave Inverter should be fine. When you come to purchase your inverter really think about what it will be powering before you purchase it.

What is a Inverter-charger

A Inverter-charger (Combi) is an all in one product that integrates - power inverter, powerful multi-stage battery charger and a high-speed AC transfer switch into one compact enclosure.

This multi-functional unit is ideal for a number of applications - Marine, in-vehicle and off-grid.

Inverter-chargers are available in both modified and pure sinewave with the latter being more popular in the majority of applications

These products allow the automatic switchover from mains 230V power to inverter and battery to ensure no interruption of power.

What battery can power an inverter?

Whether you use one battery or you compile a battery pack, there are of course many different batteries sizes and types available to connect your inverters to, these include flooded, sealed AGM and Gel which are all deep cycle batteries.

So which is the one that will best suit your Inverter?

Typically speaking, both Modified Sine Wave and Pure Sine Wave Inverters will run on either a 12v, 24v or 48V Deep Cycle battery bank, as these are the best kind to run inverters on.

How long will a battery last powering an inverter and appliances?

This very much depends on the appliances you are powering and the storage capacity of the battery.

For example, if you are powering a 100W TV for 1 hours this is 100 watt-hour of energy consumption therefore If you have a 600 watt-hour battery it will power your TV for 6 hours.

After the battery is discharged the inverter will automatically switch off and your appliances will also be disconnected. You will then need to recharge your battery using a battery charger.

To increase the runtime of appliances you can create a larger battery bank by connecting multiple batteries together in parallel.

Appliance precautions

As with all electrical appliances we would strongly recommend finding out all the information about the appliances you are planning on using through your inverter, to ensure you have the right inverter wattage and battery for the use of your appliances.

General Safety Precautions

Do not place any foreign items in or around the battery or inverter area for safety reasons.

Always make sure your battery and inverter are well ventilated so plenty of air can circulate to prevent them from overheating, which is again unlikely to happen but you can never be too careful.

Never place an inverter or battery near or in water, this will not only cause damage to both the inverter and battery but can also put lives at danger too.

View our full range of Power Inverters.

If you have any questions relating to anything power inverter or battery related, then please don’t hesitate to give the friendly team at Portable Power Tech a call. They’ll be more than happy to answer your questions and help you find the right power inverter for your needs.

For help & advice call:

+44 (0)1474 761 051



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