The energiser that you need depends on various factors. The deciding factors are, which animal you want to fence in, what power sources are available, the length of your fence, whether there is much vegetation around the fence and the moisture content of the ground. Ensure that the energiser matches your needs and the conditions.

There are different energisers depending on the type of animal you are dealing with.

Horses, cattle, pigs, dogs, cats and other pets are "easier to keep".
Normal energisers are more than adequate for these. These animals are generally used to electric fences, have short hair and therefore feel the shock pulse very clearly. The minimum effective voltage for the fence should not, however, go below 2000 V (3000 V is better) – these animals tend to escape otherwise.

Free-roaming wild animals, but also sheep, goats and poultry are "more difficult to keep".
High-performance energisers are required for these. These animals are not generally used to electric fences and also have thick hair or fur which significantly reduces their sensitivity to electric shocks. In this case, a high-voltage electric fence is required to provide the necessary safety. This voltage should not be less than 4000 volts.

You can orientate yourself using the following information:

Energisers with low pulse energy (under 1 joule)
These energisers are suitable for use with easy to keep animals and short fencing with little or no vegetation. They are also often used for special purposes such as defence against martens or pigeons.

Energisers with medium pulse energy (up to around 5 joules)
These are suitable for use with difficult to keep animals. The electric fence should be of medium length with a normal to medium amount of grass vegetation.

Very powerful energisers with high pulse energy (over 5 joules)
These are suitable for use with difficult to keep animals and very long fences with a lot of vegetation.

Please note:
on our special pages for individual animals we have put together some energisers and suitable accessories for you under Tips & Tricks . Alongside the type of animal you are keeping, the power source available is also a deciding factor for choosing the energiser.

230 V mains energiser
If a connection to mains power is available (even if it's up to 200 m away), then a 230 V mains energiser is preferred. Mains energisers are available in different performance categories. Even for long fences with a lot of vegetation and animals that are difficult to keep, these will provide sufficient energy and are therefore also suitable for complex fences. A disadvantage of mains energisers is that you will lose the voltage on the electric fence system in the event of a power cut, and it will no longer provide any security.

When using a mains energiser it is also recommended to install lightning protection (How do I install a lightning protection mechanism?). Unfortunately, it is not an uncommon occurrence for lightning to strike mains powered fences. This can lead to extensive damage being caused. The mains energiser can be destroyed and even fires are possible. It is for this reason that lightning protection (spark gap with grounding) is a legal requirement for 230 V mains energisers that are housed indoors. A ground fault circuit interrupter is also highly recommended.

Battery-powered energisers
If no mains connection is available to you, then you can use a 12 V battery unit or 9 V battery-powered energiser. Additional use of solar panels will save time and money and perfectly complements your 9 V battery-powered energiser or 12 V battery unit. (Use of solar panels) Using solar technology means you don't need to waste time with frequent battery changes, which alone makes the purchase worthwhile.

9 V battery-powered energiser
If the fence is not too long, without vegetation and the animals are easy to keep, then you can choose a 9 V battery-powered energiser. 9 V energisers are often used for internal fencing and dividing areas of land as they are lightweight and easy to handle, making them very versatile. The operating life can be anything from a few to several months depending on the energiser itself and the load. The battery must then be replaced with a new one.

12 V Battery unit
Longer fences with disturbances or animals that are difficult to keep will need a stronger energiser. For these situations you should choose a 12 V battery unit. The advantages of a 12 V battery unit versus a 9 V battery are the higher performance and the ability to recharge it. (12 V battery is the same as a car battery.) It is worth always keeping a spare battery for when it needs charging.

A few final things:
the law requires that electric fence systems are continuously monitored. Electric fences should ideally be completely free from any disturbances. Unfortunately this is rarely the case in practice. Various disturbances such as faulty insulators, overgrowth and moisture are common problems. The energiser must, however, be able to deliver the fence voltage required. You should future-proof by purchasing a more powerful energiser than you currently require.