If you're at shows or events without a mains hookup, a horsebox solar kit keeps ventilation fans running and your leisure battery topped up without relying on the engine. This guide covers sizing by actual use case, the PWM vs MPPT decision, and real UK prices sourced directly from a specialist retailer.
This guide covers 12V (or 24V) DC off-grid systems that charge your leisure battery — completely different from the mains-connected 230V AC "plug-in solar" kits covered elsewhere on this site. There's no G98 notification, no DNO, and no grid connection at all. If you're looking for balcony or garden solar for a house, see our plug-in solar legal guide instead.
Self-propelled lorry or towed trailer? It changes your setup
Horseboxes split into two distinct types, and it affects your electrics:
- Self-propelled horsebox lorries have their own engine and typically run both an engine start battery and a separate leisure battery for living quarters and equipment — similar to a motorhome. The alternator can charge the leisure battery while driving via a DC-DC charger, with solar topping it up when parked.
- Towed horse trailers have no engine of their own, so there's just a leisure battery to worry about (charged from the towing vehicle's electrics while travelling, and from solar when parked at a show or event).
Sizing by what you actually need
| Use Case | Recommended Kit | Controller |
|---|---|---|
| Trickle charging + ventilation fan only | 50W | PWM |
| Living quarters, weekend shows | 100-150W | MPPT |
| Multi-day events, fuller living quarters use | 295W+ | MPPT |
If you only need to keep a ventilation fan running and stop the leisure battery draining flat between uses, a small 50W kit is genuinely enough — don't over-buy. If you're using living quarters with lighting, charging, and small appliances over a full weekend show, step up to 100-150W.
PWM or MPPT?
PWM (Pulse Width Modulation) controllers are simpler and cheaper, and perfectly adequate for small trickle-charging kits around 50W. MPPT (Maximum Power Point Tracking) controllers harvest meaningfully more energy from the same panel — worth the extra cost once you're at 100W or above, since horsebox roof space is limited and you want to extract as much as possible from what you can fit.
Real UK prices
| Kit | Panel Type | Controller | Price |
|---|---|---|---|
| 50W Flexible Kit | Flexible | PWM | £127 |
| 100W ETFE Flexible Kit | ETFE Flexible | MPPT | £251 |
| 150W Polycrystalline Kit | Rigid Poly | MPPT | £278 |
| 295W Premium Monocrystalline Kit | Rigid Mono | 30A MPPT | £459 |
These figures are sourced directly from a specialist UK solar retailer's current horsebox kit range, so they're a genuine reflection of what's actually available to buy today, not estimates.
Recommended kit
100-150W Solar Charging Kit for Horseboxes
The sweet spot for most owners — enough to genuinely support living quarters use over a show weekend without paying for capacity you won't use. Includes panel, MPPT controller, cables and battery cable harnesses in most kits.
amazon Check Price on Amazon →If you only need basic trickle charging for a fan, a 50W flexible panel kit is a cheaper, simpler starting point. For component spares and cabling, see our solar accessories guide.
Summary — what to buy
- Fan and trickle charging only? A 50W PWM kit (£127) is genuinely enough.
- Living quarters for weekend shows? Go 100-150W with MPPT (£251-£278).
- Multi-day events or heavier use? 295W (~£459) with a 30A MPPT controller.
- Know your setup: self-propelled lorries have two batteries to consider; towed trailers just have the leisure battery.
Browse horsebox and trailer solar charging kits on Amazon UK.
🐴 Browse Horsebox Solar Kits on Amazon →Frequently Asked Questions
Do I need solar panels on my horsebox?
Not essential, but genuinely useful if you spend time at shows or events without a mains hookup. Even a small kit keeps a ventilation fan or leisure battery topped up so you're not relying on the engine or arriving with a flat battery, which matters more for horse welfare and comfort than convenience alone.
What size solar panel do I need for a horsebox?
For trickle charging and running a fan only, a 50W kit is sufficient. For living quarters with lighting and small appliances used over a weekend, 100-150W is more realistic. For multi-day events or fuller living quarters use, 295W or a larger bespoke system is worth considering.
Does a horsebox need a separate leisure battery and engine battery?
Self-propelled horsebox lorries typically have both an engine start battery and a separate leisure battery for living quarters and equipment, similar to a motorhome. Towed horse trailers usually only have a leisure battery, since there's no engine. Solar panels are wired to charge the leisure battery in both cases; self-propelled boxes may also use the alternator to charge it while driving.
PWM or MPPT controller for a horsebox solar kit?
PWM controllers are fine for small kits (around 50W) used for basic trickle charging. MPPT controllers harvest meaningfully more energy and are the better choice for 100W and above, especially since horsebox roof space is limited and every extra bit of harvested energy matters.
How much does a horsebox solar kit cost in the UK?
A basic 50W flexible panel kit with PWM controller costs around £127. A 100W ETFE flexible kit with MPPT runs around £251. A 150W polycrystalline kit is around £278, and a premium 295W monocrystalline kit for larger installations is around £459.