https://nemtek.com.au/product/agri-solar-50km-energizer/

The Agri – 50 km solar range of energizers includes a solar panel, which is used to charge a battery during the day to power the energizer. Solar panels are usually provided with a separate solar regulator, but the Nemtek Agri solar range of energizers has a built-in solar regulator. This makes the energizer more portable and makes connecting of the energizer easier. The built-in regulator has a smart management system to maximise battery life and ensure efficient power management to the fence. These energizers also come with built-in polarity protection for the battery and the solar system to protect them in the event of an incorrect connection. 
The energizers use Nemtek APT technology, which ensures maximum power is delivered to the electric fence while minimising power losses along the fence line. With APT the energizer responds to changing environmental factors (such as changes in weather and vegetation growth on the fence), and adapts the changing needs of the fence to maximise fence power and efficiency.

Features:
• Powers up to 50 km of fence (applies to optimal fence conditions)
• Robust weather resistant system
• Battery charge state indicator
• Energizer overload indicator
• Output energy max 4.6 J (stored energy 6.5 J)
• Powered by 40 watt solar panel (included) and 50 Ah 
battery (sold separately)
• Built-in solar regulator with power management system 
for easier connection and portability
• Built-in battery polarity protection
• Day/night sensor
• Adaptable mounting options (wall, fence wire or wooden 
post and also slides onto Y picket post)
• Lightning protection
• Many programmable options via the LCD handheld remote 
(optional accessory) including adjustment of fence voltage 
and pulse rate, independent day/night setting, battery 
voltage reporting and fence performance monitoring