About the Campervan Power Planner

The Campervan Power Planner is a free online tool built by Rayne Automotive to help van converters and campervan owners design a complete, safe, and correctly sized 12V electrical system. Whether you are converting a panel van from scratch or upgrading an existing leisure battery setup, the planner walks you step by step through every decision — from the appliances you want to run, through solar panel and DC-DC alternator charger sizing, to the right inverter, battery capacity, and wiring method for your build.

The tool is designed for anyone planning a campervan, motorhome, or off-grid vehicle electrical system in the UK and beyond. DIY converters use it to understand exactly what components they need and why, while professional installers use it to produce consistent, transparent quotes and wiring diagrams for their customers. By calculating your daily power consumption in watt-hours and matching it to the correct lithium leisure battery, flexible solar panels, MPPT charge controller, and mains hook-up options, the planner removes the guesswork and helps you avoid expensive mistakes like an undersized battery or an inverter that cannot handle your peak loads.

Rayne Automotive is a UK-based specialist in campervan electrical systems and components. We design, supply, and install complete 12V and 240V kits — from lithium batteries and Victron Energy charge controllers to pre-wired power boards and custom wiring looms. The Power Planner reflects the same real-world engineering and product knowledge we use every day in our workshop, so the recommendations you receive are based on products we actually stock, test, and stand behind. Our goal is to make safe, reliable campervan electrics accessible to everyone, with clear guidance and transparent pricing at every step.