For small to medium fence lines (up to 2 km), a dependable battery energiser is a simple and effective way to keep livestock safe and contained. Portable, easy to set up, and perfect for temporary or rotational grazing, battery units provide a flexible alternative to mains or solar systems. They’re an affordable, practical choice for short runs and smaller paddocks.
In this guide, we compare three of the most popular options in the UK: the Gallagher BA20, the Horizont Trapper B12, and the Hotline HLB25 Merlin. We’ll break down each unit’s usability, durability, performance, and design, helping you choose the energiser that best suits your setup, whether it’s a small hobby paddock or a medium-sized field.
Our winners of 2026
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OUR WINNER: Gallagher BA20 9V/12V Battery Fence Energiser
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| A compact and lightweight battery energiser that’s perfect for small paddocks and short fences. The BA20 runs from either a 9 V or 12 V battery, giving you flexibility and effortless setup, ideal for hobby farmers or portable fencing needs. |
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Our rating by category
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Usability: The Gallagher BA20 is one of the most straightforward battery energisers to set up — simply connect a 9 V or 12 V battery and go. Its compact and lightweight design makes it easy to move between paddocks or temporary fences, and clear LED indicators show both energiser and battery status at a glance. Known for being very user‑friendly, it’s ideal if you’re after simple, reliable performance without complication.
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Durability: Built with weather‑resistant protection and splash‑proof casing, the BA20 is designed to handle typical UK outdoor conditions. Its robust enclosure and built‑in lightning protection add reassurance against moisture and electrical surges, so it keeps going even when the weather’s not on your side.
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Performance: With about 0.17 J stored energy and 0.12 J output, this energiser is well matched to short fences — up to around 2 km under ideal conditions. It’s perfect for hobby farms, small fields or rotational grazing, giving reliable electric pulses for horses, cattle, pigs and pets.
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Design: The BA20 keeps things simple but practical, with a rugged black housing, carry handle and easy battery connection. Its splash‑proof casing and visible status LEDs make daily checks and maintenance straightforward — ideal for busy smallholders.
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2. Hotline Merlin Battery Energiser
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| The Hotline Merlin strikes a solid balance between power and portability. With a 6 V internal backup and the option to use a 12 V external battery, this mid‑powered energiser delivers dependable performance for slightly larger small–medium setups. |
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Our rating by category
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Usability: The Hotline Merlin sits in the middle of the range, offering a step up in power while staying easy to use. It accepts a 12 V external battery, with a 6 V internal backup battery built in — giving you flexibility and decent run times. Simple indicators for pulse and low battery help you keep tabs on performance without fuss.
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Durability: This energiser has a tough, compact design with a secure stand that doubles as a mounting spike. Built to British specs with solid construction and a generous 5‑year warranty, it’s a reliable choice for smallholders who want long‑lasting hardware.
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Performance: With around 0.44 J stored energy and 0.35 J output, the Merlin outpaces most entry‑level units, comfortably energising up to about 2.2 km of single‑line fencing in ideal conditions. That extra power makes it suitable for slightly larger layouts or heavier vegetation compared with simpler 9 V energisers.
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Design: The design is practical and purpose‑built, with all‑in‑one controls, low battery and pulse indicators, and a solid stand for field use. It’s not flashy, but it’s thoughtfully put together for everyday small to medium fencing duties.
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3. Horizont trapper B12 Battery Energiser
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The Trapper B12 is a versatile 9 V/12 V energiser built for small and simple fencing systems. With clear pulse indicators and a handy carrying handle, it’s a user‑friendly option for beginners and smallholders looking for reliable battery‑powered fencing.
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Our rating by category
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Usability: The Horizont Trapper B12 is aimed at beginners and small‑scale users who want a flexible battery energiser that works with either 9 V or 12 V batteries. It includes an ergonomic handle and easy on/off switch, plus a flashing pulse indicator so you can see it’s active from a distance — great for mobile or temporary setups.
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Durability: Made from UV‑resistant, impact‑resistant polycarbonate, the Trapper B12 is built to cope with knocks, weather and regular handling. Its housing also acts as a transport box for the battery, helping protect your power source when moving between fields.
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Performance: With roughly 0.18 J stored and 0.12 J output, this energiser can power fences up to a few kilometres in light conditions (around 1 km with medium vegetation). It’s ideal for smaller paddocks, gardens or hobby livestock. Optional solar assist capability adds extra flexibility if you want to extend battery life.
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Design: Horizont has kept the design compact and practical, with a carry handle and robust build that feels solid in use. The integrated solar charging control (if used) and simple controls make this a handy unit for beginners or occasional use.
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Conclusion
All three of these battery energisers are excellent choices, offering reliable pulses, durable construction, and easy operation for small-to-medium fencing setups. While their core performance is broadly similar, your choice may come down to personal preference, brand, or the specific design features you value most. The Gallagher BA20 takes the lead as the most user-friendly and versatile, making it perfect for quick setup and everyday reliability. The Horizont Trapper B12 earns second place with its flexible battery options and rugged, compact design. Finally, the Hotline HLB25 Merlin delivers slightly higher power and longer reach, giving you extra capability for slightly larger or denser fencing layouts. No matter which energiser you choose, each one is a dependable option that will keep your fences running smoothly year-round.
This independent test was carried out based on performance data, physical testing, and our expertise in electric fencing equipment. For this test, we used only devices from our own range and did not include models from other manufacturers or brands. We received no financial or other incentives from the manufacturers for the ratings awarded.
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