Whether it is keeping livestock in or vermin out, electric fencing has been an important part of the farmer’s armoury for a long time. The drawback for isolated fields has always been keeping fences powered.

Lugging a heavy battery across a squelching field is less than ideal, and the second the power runs out, whatever is behind the fence seems to instantly know.

Solar power has been helping with this issue and extending the lifetime of the charge for several years. We took a look at what is on offer in the UK.

See also: Twelve tips for perfect fencing

The Wolseley SX300

These British-made units, have a two-year warranty. They combine solar power, rechargeable batteries and back-up C-cell batteries to ensure that it stays awake even at night and on cloudy days.

Unlike a leisure battery, C-cells can be replaced cheaply after a few years, when the batteries are getting a bit tired. You can always pick up a pack of them at the garage.

Wolseley says the unit can run for 12 months without the user having to change them.

The SX300 has a few nifty features such as night time energy saving and indicator lights that show solar output and battery condition. It is claimed to power 20km of wire too.

Sold by Stockshop in Exeter, at £216, it is by far the cheapest here.

Rutland ESB225

Rutland is the new-comer to the market in comparison with the other two companies. Although, Young Farmers would have seen their sponsorship stamped on a lot of events.

The leisure battery-powered energiser has a 10W solar panel to charge the power unit and stores 1.6J. The products economy setting will slow the energiser during darkness to extend battery life.

The battery saver setting prevents the battery from being completely discharged.

If the stainless steel crocodile clips were connected to 22km of wire, Rutland say it will power the lot. With a whopping 9,500V, even the most stubborn bull should feel this one, and should certainly deter rabbits from wheat.

With the price set at £308, it is the most expensive, but comes across as a good all-rounder.

Speedrite S500

Rappa have been a big name in the electric fencing market for a while and are the UK distributor for Speedrite energisers. They say this product delivers peak performance in low sunlight, so is ideal for the UK climate.

This energiser is designed to make it easy to mount on wood or metal posts. This should help it catch sunlight and, as these are meant to be left alone for a while, should stop it getting caught in the undergrowth.

Like the others, it has a pulse indicator and a battery saver mode, so batteries are understood to last three or more years. These batteries are 12V 7Ah, and are internally sealed.

Comfortably mid-range at £285, the sealed in battery would worry a lot of people, but its versatile design should pay off.