Gallagher S20 Lithium Solar
#10 in Battery and solarFull review
A portable lithium solar charger for rotational grazing and small pastures, if you value Gallagher’s battery and warranty over raw output.
Amazon $289.99$289.99
The Gallagher S20 Lithium Solar is the better electric fence energizer overall, rated 2.7 to 2.6. The Gallagher S20 Lithium Solar leads on warranty. The Zareba 15 Mile Solar ESP15M-Z wins on lightning cover. The Zareba 15 Mile Solar ESP15M-Z costs $90 less ($199.99 vs $289.99).
Zareba 15 Mile Solar ESP15M-Z
#12 in Battery and solarFull review
A self contained solar charger for larger remote pastures with some weeds, for cattle, horses and goats.
Amazon $199.99$199.99
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Gallagher S20 Lithium Solar for warranty (3-year warranty vs 1-year warranty).
- Choose the Zareba 15 Mile Solar ESP15M-Z for lightning cover (warranty covers lightning damage vs lightning damage not covered).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every battery and solar electric fence energizer; a clear win is highlighted. How we rank explains each one.
| Factor weight | Gallagher S20 Lithium Solar | Zareba 15 Mile Solar ESP15M-Z |
|---|---|---|
| Overall rating | 2.7/5 | 2.6/5 |
| Value 35% | 10 $1,933.27 per joule ($289.99, 0.1 J output) | 23 $1,111.06 per joule ($199.99, 0.2 J output) |
| Output 25% | 25 0.1 J output | 29 0.2 J output |
| Warranty 25% | 100 3-year warranty | 0 1-year warranty |
| Lightning cover 15% | 0 lightning damage not covered | 100 warranty covers lightning damage |
Specifications
| Gallagher S20 Lithium Solar | Zareba 15 Mile Solar ESP15M-Z | |
|---|---|---|
| Output | ||
| Power | Solar | Solar |
| Output energy | 0.1 J | 0.2 J |
| Stored energy | 0.2 J | - |
| Rated fence length | 12 miles | 15 miles |
| Rated area | 40 acres | - |
| Peak voltage | 9.3 kV | - |
| Low impedance | - | Yes |
| Build | ||
| Battery | - | 6 V |
| Solar panel | 3 W | - |
| Lightning cover | No | Yes |
| Warranty | 3 years | 1 year |