Electric fence energisers come in several types depending on your needs, the three main types are:
Solar powered energisers
Solar powered energisers either come with an in-built solar panel or are compatible with external solar panels. The solar panel will charge the battery during daytime to power it all through the night. Solar panels will power your energiser even during cloudy winter days. They are excellent for providing fencing in locations where mains power is not available.
Mains powered energisers
Mains powered electric fence energisers must be linked up to mains power, they provide excellent power and are good for long lengths of fencing. The drawback is that they must be installed in locations which can access the mains electricity network.
Battery powered energisers
Battery powered energisers are the cheapest energisers, powered by 6v, 9v or 12v batteries and can often be paired with a solar panel to dramatically extend the length of time they can provide power for. Some battery powered fence energisers can also be connected to mains power.