Van, RV and boat electrical
Wire your rig right, once.
Two free tools. Tell the planner what you run and where you camp; it sizes the battery, solar, alternator charger, inverter and every wire and fuse, then prices the parts. Then draw it, with the gauge and fuse printed on every cable.
Tool 1
Rig power planner
Your loads, days off-grid, state and month in. A complete system out, with the math shown.
- Daily use
- 1,731 Wh
- Battery
- 2 x 200 Ah
- Solar
- 400 W
- Inverter
- 1,000 W
- Main cable
- 1 AWG, 150 A fuse
- Priced parts
- $2,136
Sample: full-time van with Starlink Mini and a diesel heater, Colorado in October.
Plan my systemTool 2
Draw your wiring
Drag standard parts, connect them, and every cable gets its gauge and fuse. Download a PNG to take to the van.
Open the wiring toolWhat the other calculators leave out
Every wire and every fuse
Most calculators stop at battery and solar. Ours sizes the main cable, inverter cable, charger runs and fuse block feed, from the ABYC tables, for your cable lengths.
Your state, your month, a flat roof
Sun hours come from a solar model run for a flat van roof in all 50 states and DC, month by month. December in Seattle is not June in Phoenix.
Real prices, today
Every price is read from the maker's own site, with the date. If we couldn't confirm a price, we left it out.
The math, out loud
Open "Show the math" and every number is there: efficiency, reserve, headroom. Change anything you disagree with.
Myth
"Lithium is too expensive."
A Redodo 12V 200Ah Plus cost $449.99 on Redodo's site today for 2,560 Wh. To get the same usable energy from AGM you need about twice the rated capacity, because AGM should only be run down halfway, and it wears out in hundreds of cycles, not thousands. Per year of use, lithium is usually the cheaper battery. The full conversion math.
Myth
"You need a huge inverter."
A laptop, a CPAP and camera chargers need about 200 W. A Renogy Pro 1000W Pure Sine Inverter (12V) ($222.99) covers them with room to spare, on far thinner cable than a 3,000 W unit. Size the inverter for the biggest thing you'll actually plug in; a Redodo 2000W Pure Sine Inverter (12V) ($205.99) already runs a microwave or a coffee maker.
Guides that back up the tools
All guidesVan electrical basics
The six parts every camper system has, how they connect, and a diagram to download.
Wire gauge and fuse chart
12 V and 24 V wire sizes and fuses by amps and run length, from the ABYC tables.
How many solar panels
What 200, 400 and 600 W of flat roof panels make in your state, month by month.
DC-DC charger sizing
20 A or 40 A, smart alternators, and what an hour of driving puts back.
Lithium conversion
Swapping lead-acid for lithium: what it costs and the three things that must change with it.
Best lithium battery for a van
Redodo and LiTime batteries by price per usable watt-hour, BMS current and cold-weather charging.
Power station vs built-in
When a Bluetti box beats a wired system, and when it costs you more.
Shore power and EV charging
30 A and 50 A plugs, what they really deliver, and charging an EV at the campground.
Boat house battery upgrade
Adding a lithium house bank beside your starting battery without cooking the alternator.
Wiring a house, not a van? Our sister site Spark Powered covers home solar, batteries and EV charging.