The only free tool that handles 12V, 24V, and 48V systems with ABYC-standard wire sizing, a solar generator finder, and live system diagrams. Built for serious DIYers.
Built for the DIY RV electrician who wants professional-grade results without a professional price tag.
Full support for 12V, 24V, and 48V systems with voltage-appropriate wiring diagrams, compatibility checks, and component recommendations. Most free tools cap at 12V.
Exclusive to this toolBattery Ah, solar watts, charge controller, inverter VA — all calculated live as you type. Includes 20% battery buffer, 25% solar buffer, and cloud day SoC simulation.
Professional marine/RV standard cable sizing for every circuit segment. Enter your run length and get the correct AWG and fuse size — with derating for bundled, hot area, and continuous loads.
Pro standardShould you buy an EcoFlow or build a system? The app answers this based on your actual load profile, ranks 10 generators by fit, and shows a live DIY vs generator cost comparison.
Unique feature25+ locations with annual, summer, and winter PSH values. Orange warning fires if your winter solar drops more than 40% — so you don't size for average and freeze in July.
Runs your system against 30 days of real historical solar radiation data from Open-Meteo — not a random model. See battery SoC day-by-day, deficit days, lowest charge reached, and a clear pass/warn/fail verdict.
Better than competitorsAutomated checks for CC voltage Voc limits, high-current warnings, DC-DC converter requirements on 24V/48V systems, and AC voltage matching. Flags issues before you buy.
Multi-select batteries, panels, and inverters — including dual-inverter setups. Built-in database of Australian brands including Renogy, Enerdrive, Victron, Redarc, Projecta, BMPRO, iTechworld, and Baintech. Type a brand or model in the quick search to find and add products instantly. Set per-product quantities, add custom items from any retailer, and get a shopping list with line totals. Prices are region-aware — switch between AU, US, UK, CA, and EU via the Shop selector.
Voltage-aware SVG schematic updates as you change your system. Four variants: 12V simple, 12V high-current, 24V with DC-DC block, and 48V with isolation warnings. Select a battery, inverter, or charge controller in the Components tab and the diagram updates to show the actual product name, Ah, and watts — not just calculated estimates.
Save multiple designs, compare them side-by-side across all metrics, export JSON for backup, and share via URL. Your designs stay in your browser — no account needed.
The guided setup wizard gets you to a first estimate in about 60 seconds.
5 quick questions about your rig, camping style, key loads, and location. The app configures voltage, battery type, autonomy, and sun hours automatically.
Add appliances manually, load a Quick Template, or browse the built-in reference library of 42 common RV appliances to find typical wattages. Every change recalculates battery Ah, solar watts, inverter VA, and daily balance instantly.
Check sizing results, run a 30-day weather simulation on real historical data, review compatibility alerts, get ABYC wire sizes for every cable run, select components, and share or export your finished design.
Most people don't know which path makes sense for their setup. The Solar Generator Finder uses your actual load profile to give you a data-driven answer — and compares both options honestly.
Brands covered
Each ranked by capacity fit, inverter adequacy, solar input, and value for your specific load.
Select your location, hit Run — and see exactly how your battery would have fared over the last 30 days of actual recorded weather. Not a random model. Not an average. Real radiation data from Open-Meteo's free historical archive.
Free and paid tools compared. The only columns that matter are the ones that affect your actual build.
| Feature | ⚡ RV Power Designer Free |
FarOutRide Free + paid wiring |
SotaSolar Free |
Mowgli Adventures Free |
Victron Click & Design Free (account) |
|---|---|---|---|---|---|
| 12V support | ✅ | ✅ | ✅ | ✅ | ❌ 48V only |
| 24V support | ✅ | ❌ | ✅ | ❌ | ❌ |
| 48V support | ✅ | ❌ | ✅ | ❌ | ✅ |
| Wire sizing (run-length) | ✅ ABYC E-11 | ⚡ Basic AWG | ❌ | ❌ | ⚡ Victron only |
| Seasonal sun hours | ✅ 25+ locations | ⚡ Presets | ❌ | ❌ | ✅ Real data |
| Compatibility validation | ✅ Voc, current, DC-DC | ⚡ Partial | ❌ | ❌ | ✅ |
| Solar generator finder | ✅ 10 models, ranked | ❌ | ❌ | ❌ | ❌ |
| Guided onboarding | ✅ 5-step wizard | ❌ | ❌ | ❌ | ❌ |
| Save / compare / share | ✅ | ⚡ Amazon cart | ❌ | ❌ | ✅ Account-based |
| Live system diagram | ✅ 4 voltage variants | ✅ Paid ($40) | ❌ | ❌ | ✅ |
| Weather simulation | ✅ Real 30-day data | ❌ | ⚡ Random 7-day | ❌ | ✅ |
| No account required | ✅ | ✅ | ✅ | ✅ | ❌ |
| Cost | Free forever | Free + $40 diagram | Free | Free | Free (Victron only) |
Most calculators tell you to "use 6 AWG." That's not good enough. RV Power Designer sizes every cable run to ABYC E-11 — the same standard used by marine electricians and professional RV builders.
Enter the actual one-way cable length for each segment. Voltage drop is calculated from real resistance values across 12 AWG sizes from 14 AWG to 4/0.
Tick which conditions apply: bundled/conduit (×0.70 ampacity), hot area ≥50°C (×0.85), and continuous load >20 min (×1.25 design current). Most tools ignore these entirely.
The result is always the worst-case of ampacity and voltage-drop limits. The label tells you which constraint applies — VD↑ or A↑ — so you understand your design.
The only free tool that handles 24V and 48V systems properly. If you're building anything beyond a basic 12V van setup, this is what you need.
No signup. No paywall. No nonsense. Your complete RV electrical design in one tool.
⚡ Launch RV Power Designer