Check your shore power load against the NEC 80% rule, estimate battery runtime for boondocking, and right-size your solar + battery + inverter system. No sign-up. Instant results.
Whether you are plugging in at a campground or heading off-grid, get the numbers you need instantly.
Shore Power Check
Is your hookup big enough? Check against the NEC 80% continuous-load rule.
Off-Grid Runtime
How many days will your batteries last given your loads and solar input?
System Builder
What size battery, solar panels, and inverter do you actually need?
This tool is in beta. Always double-check your results against your manufacturer specs and a certified scale before every trip.
Hookup Type
Appliances — check what you plan to run simultaneously
Climate
Kitchen
Entertainment
Utilities
Lighting
Work / Office
Outdoor / Rec
Shore Power Result
PassLoad vs. Safe Limit
0% of safe capacity
Free electrical planning is just the start. Track your trip route, coordinate with your travel group, and get campground alerts — all in one app.
Shore Power — Campground Electrical Hookup
AC power from the campground pedestal. Available at 15A, 20A, 30A, and 50A. 50A service is two-leg 120V giving 12,000W total — not 6,000W.
NEC 80% Rule — Continuous Load Limit
National Electrical Code requires continuous loads stay at or below 80% of circuit capacity. A 30A/3,600W hookup is safe only up to 2,880W continuously.
DoD — Depth of Discharge
How deeply you drain a battery before recharging. Lithium: 80%, AGM: 60%, Lead-acid: 50%. Exceeding DoD shortens battery life significantly.
Peak Sun Hours — Effective Solar Hours Per Day
Hours of sunlight equivalent to 1,000 W/m² — not total daylight. The US average is 4–6 hours. Arizona gets ~6.5; Pacific Northwest ~4.
Solar Derate — Real-World Panel Efficiency Loss
Panels rarely output rated watts due to heat, shading, wiring, and angle. A 75% derate factor (×0.75) accounts for real-world losses.
Inverter — DC-to-AC Power Converter
Converts 12V/24V/48V battery power to 120V AC for appliances. Size it 25% above your peak load to handle surge current without tripping.
Surge Watts — Motor Start Power
Electric motors (AC, fridge, pump) draw 2–3× their running watts for the first second on start. Inverters and generators must handle surge, not just running load.
AGM — Absorbed Glass Mat Battery
Sealed lead-acid battery with no maintenance. Heavier and less DoD-friendly than lithium but lower upfront cost. Safe to 60% DoD routinely.
Thinking 50A = 6,000W
50A service is a two-leg system: 50A × 120V × 2 = 12,000W. You get double the power of 30A, not 66% more. Critical when running two air conditioners.
Discharging batteries too deep
Running lithium past 80% DoD shortens cycle life. Lead-acid past 50% DoD can sulfate permanently. Your usable capacity is always less than the nameplate Ah.
Using panel rated watts as actual output
A 400W panel in real life produces 280–320W after heat, angle, and wiring losses. Always derate by 25% (×0.75) for realistic planning.
Forgetting AC start surge
A 13,500 BTU AC runs at ~1,300W but starts at 2,800W+. That surge must fit within shore power AND your inverter's peak rating — not just running wattage.
Assuming 5 peak sun hours everywhere
Peak sun hours vary from 3.5 (Pacific Northwest winter) to 6.5 (Arizona summer). Always size solar conservatively for your worst-case destination.
The 80% NEC rule catches people off-guard
30A shore power feels like 3,600W but safe continuous draw is only 2,880W. Add a battery charger and a microwave and you're already tight.
RVGather connects your trip planning with your community. Free electrical tools are the start — here is what else is waiting for you.
Trip Map & Stop Planner
Plan your route with electrical hookup info for each campground — 30A vs 50A, dry camping areas, and generator hours.
Reservation Alerts
Get notified before check-in so you can pack your adapters, prep your solar setup, and know what to expect at the site.
Gatherings & Meetups
Find boondocking groups and off-grid meetups near you. Share solar and battery setups with the community.
Campground Power Info
Community-reported hookup quality, pedestal amp ratings, and power reliability ratings — straight from RVers who've been there.
Why does 50A service give 12,000W and not 6,000W?
50A service at RV parks is a two-leg 120V system: each leg carries 50A at 120V (6,000W), and both legs run simultaneously — giving 12,000W total. It is NOT 50A × 240V.
What is the NEC 80% continuous load rule?
The National Electrical Code (NEC) 310.15 requires that continuous loads — anything running for 3 hours or more — stay at or below 80% of circuit capacity. On a 30A hookup (3,600W), that means 2,880W maximum. This prevents breaker overheating.
How many peak sun hours does my area get?
Peak sun hours are the equivalent hours of full 1,000W/m² sunlight per day. The US average is 4–5 hours. The Southwest (AZ, NM, NV) gets 5.5–6.5. The Pacific Northwest gets 3.5–4.5 in winter. Use 4 hours as a safe conservative estimate.
Why do I need to add 25% headroom to my inverter?
Electric motors (air conditioners, refrigerators, water pumps) draw 2–3× their running watts for the first 1–2 seconds on startup. An inverter must handle this surge without tripping. Sizing to 125% of peak running load gives comfortable surge headroom.
How long will my batteries last overnight?
This depends on your chemistry and load. Lithium at 200Ah (12V) has 1,920Wh usable. If you're drawing 100W (TV + lighting + fan), you'll use 800Wh overnight (8 hours) — 40% of capacity. Add solar to offset daytime loads.
What size battery bank do I need for off-grid camping?
Start with your daily Wh needs (watts × hours of use). Divide by your battery's DoD, then add 20% buffer. For 1,600Wh/day on lithium: 1,600 ÷ 0.80 × 1.20 = 2,400Wh = 200Ah at 12V.
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