Free power planner for US vans & RVs
Your van's off-grid power, planned in 5 minutes.
Tell us what you'll run — fridge, laptop, lights, water pump. We'll size your battery, solar, inverter and every wire, and give you a complete wiring diagram and parts list — built to US standards, priced in dollars.
Free · No experience needed · Built to NEC & manufacturer guidance
Not a number. A complete design.
Most calculators give you a battery size and wish you luck. Roam Wired gives you the whole system: an interactive wiring diagram, a cable schedule, a fuse schedule, a parts list, and step-by-step installation notes — every value traceable to a real calculation.
Three steps. No jargon.
You don't need to know what a watt-hour is. Answer plain questions, get a professional design.
Pick your appliances
Fridge, laptop, lights, water pump, vent fan — tick what you'll run and how long you'll use it each day.
Choose your preferences
Battery type, budget, solar, days off-grid. We handle every calculation behind the scenes.
Get your design report
Wiring diagram, cable & fuse schedules, parts list in USD, and install notes — free, in about 5 minutes.
Calculated, not guessed.
Forum threads disagree. YouTube comments argue. Your design shouldn't depend on whichever opinion you read last.
Built on real standards
Every recommendation follows Victron's Wiring Unlimited, Blue Sea / ABYC E-11 guidance, and NEC Article 551 — the US code for electrical systems in recreational vehicles.
Show-the-maths transparency
Click any component or cable in your diagram and see the exact calculation behind it. No black boxes, no 'trust us'.
Honest about limits
Anything involving 120V shore power or an inverter's AC output, we'll tell you plainly: have it done or signed off by a licensed electrician.
Your free design report includes:
A van electrical design like this runs $200–$400 from a professional designer. Yours is free.
Interactive wiring diagram
Every component and cable in your system, laid out and connected.
Cable schedule
The exact size for every run, sized for current and voltage drop.
Fuse schedule
Every fuse rating calculated to protect its cable — including the main battery fuse.
Full parts list in USD
US components (LiTime, Battle Born, Renogy, Victron) from the battery down to the last fuse holder.
Installation notes in build order
What to install first, what to connect last, and what to double-check.
Every assumption listed and sourced
See exactly what we assumed and where each rule comes from.
Questions, answered.
Is it actually free?
Yes. The full design — wiring diagram, cable schedule, fuse schedule, parts list and installation notes — is free. We earn a small commission if you buy parts through our links, at no extra cost to you. That keeps the tool free for everyone.
Do I need any electrical experience?
No. The tool asks plain questions — what appliances you'll use and for how long — and handles all the calculations. Every recommendation is explained in plain English, and anything that needs a licensed electrician (like 120V shore power) is clearly flagged.
Does it work for my van or RV?
Yes. The design principles are identical across panel vans, RVs and trailers — Mercedes Sprinter, Ford Transit, Ram ProMaster, travel trailers and Class B/C motorhomes. The design is based on your appliances and usage, not the badge on the hood.
Can I trust the numbers?
Every value is traceable. Cable sizes satisfy both current capacity and voltage-drop limits, fuses are sized to protect their cables, and the rules come from Victron's Wiring Unlimited, Blue Sea / ABYC E-11 guidance and NEC Article 551. Click any component in your diagram to see the actual calculation.
Go deeper
Buying guides for portable power stations and off-grid power.
AWG wire size chart for van and RV 12V electrical circuits — ampacity, voltage drop, and what gauge to use for each common load.
The best pure sine wave inverters for van and RV electrical systems in 2026, sized for different power needs and budgets.
The most common mistakes in DIY van and RV electrical builds in the US — undersized wire, missing fuses, wrong charge profiles, and more.
Stop second-guessing your build.
Five minutes from now you could have your complete power design — every wire, every fuse, every part.
Get my free designFree · No sign-up to start · Takes about 5 minutes