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Electric Fence Energizers
The right electric fence energizer is the heart of every reliable system — it controls how many miles of fence you can power, how hard the shock hits, and how dependably your livestock stay contained. Powerflex carries AC plug-in energizers, portable solar and battery units, dual AC/DC chargers, and lithium solar systems from Speedrite, Gallagher, Cyclops, and other trusted brands. Many are app-controlled with remote fence testers and built-in lightning protection.
Not sure how big an energizer you need? Try our free electric fence charger sizing calculator — answer five questions and get a matched product recommendation across AC, solar, DC, and dual options. Or read our grazier's guide to sizing your charger for the long version.
For the fundamentals before you spec the rest of the system, see our complete guide to building electric fence and the guide to picking the right fence wire.
Joule sizing at a glance
The 1-joule-per-mile rule of thumb is the starting point. Numbers below are output joules — the energy actually delivered to the fence, not the marketing “stored” figure. For multi-strand fence, multiply physical miles by the number of energized strands (a 3-mile, 3-strand fence = 9 miles of energized wire).
| Miles of energized wire | Typical conditions | Heavy vegetation / dry soil |
|---|---|---|
| ≤1 mile | 0.5–1 J | 1–2 J |
| 1–5 miles | 1–3 J | 3–6 J |
| 5–15 miles | 3–8 J | 6–15 J |
| 15–30 miles | 8–15 J | 15–30 J |
| 30–60 miles | 15–30 J | 30–50 J |
| 60+ miles | 30–50 J | 50–86 J |
Power source at a glance
| Power source | Best for | Joule ceiling in our lineup |
|---|---|---|
| AC mains | Permanent perimeter near a building outlet — highest joule-per-dollar | 86 J (Speedrite 86000W) |
| DC battery | Portable paddocks, no-grid areas, low-cost entry | 12 J (Cyclops SUPER DC) |
| Solar (lithium) | Off-grid, rotational paddocks, set-and-forget operation | 4 J (Gallagher S400 Solar) |
| Multi-power (AC + DC + solar) | Operations rotating one energizer between locations | 71 J (Gallagher M10,000i) |
Top picks by use case
- Made in USA & strongest lightning protection: Cyclops BOSS 32 J AC — the only US-made option in our lineup, used by NRCS and EQIP projects.
- Smart fence with phone monitoring: Gallagher i-Series Fence Monitor paired with any MBS-series multi-power energizer.
- Off-grid lithium solar: Gallagher S400 Solar — 4 joule, runs through 14+ cloudy days.
- Largest commercial operations: Speedrite 86000W — 86 joule mains with Bluetooth/Wi-Fi remote control.
- Quick-deploy portable corral: Gallagher SmartFence 2 — all-in-one 328-ft system with posts, reel, and wire integrated.
- Budget portable starter: Cyclops CHAMP 5 J DC — American-made battery energizer for small paddocks.
Two reference pages to spec the right unit:
- Energizer technical reference — joule sizing tables, voltage targets by species, grounding math, lightning protection specs, IEC/UL/USDA standards.
- Brand comparison: Speedrite vs Gallagher vs Cyclops vs Patriot vs Zareba — head-to-head on origin, joule ceiling, features, warranty, and what each brand is actually best at.
Free shipping on orders over $150. Powerflex has been supplying ranchers and rotational graziers since 1994.
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