Reference · Updated June 2026

Off-grid by the numbers

Fourteen counterintuitive, sourced numbers about powering and living in a van, RV, or sailboat, each computed from one of our free calculators. Why flat solar panels lose half their winter output, why your generator can't start the air conditioner, why upload speed (not download) breaks video calls, and more.

Solar and batteries

A flat-mounted solar panel loses 40 to 55 percent of its output in midwinter, and roughly 10 to 22 percent a year.

Most RV and van roof panels are bolted flat for driving, which works in summer but badly misses the low winter sun. Tilting toward the sun recovers most of that loss, with the biggest gains in winter and at higher latitudes.

Source: NREL PVWatts; computed by the Solar Panel Angle Calculator. Run it: Solar Panel Angle Calculator →

The best year-round panel tilt is your latitude times 0.76, plus about 3 degrees, not your raw latitude.

At 40 degrees north that is about 34 degrees facing true south, not 40. Diffuse sky light favors a slightly flatter panel than the old latitude rule suggests.

Source: Charles Landau; pveducation.org. Run it: Solar Panel Angle Calculator →

A 100 Ah lead-acid battery gives you only about 50 usable amp-hours; the same 100 Ah in lithium gives about 80.

You can safely pull a lithium battery down to roughly 80 percent and lead-acid to about 50 percent. Lead-acid also loses up to 40 percent more capacity under a hard inverter draw (the Peukert effect), where lithium barely flinches.

Source: Battery University; computed by the RV Battery Runtime Calculator. Run it: RV Battery Runtime Calculator →

A typical van pulling about 78 amp-hours a day needs roughly a 215 Ah lithium bank and 305 watts of solar.

That assumes two days of reserve and an average 4.5 peak sun-hours. The catch most people miss: size the array to your worst travel month, not the annual average, or you run short exactly when the sun is lowest.

Source: Computed by the RV Solar & Battery Calculator. Run it: RV Solar & Battery Calculator →

Generators and propane

Starting watts, not running watts, set generator size: a 13,500 BTU RV air conditioner runs at about 1,400 watts but surges to roughly 2,900 to start.

That is why a 2,000 watt generator that looks big enough on paper trips out the instant the compressor kicks on. Size for the single largest startup surge, not the steady draw.

Source: Champion and Honda wattage charts; computed by the Generator Sizing Calculator. Run it: Generator Sizing Calculator →

A soft-start device cuts an RV air conditioner's startup surge by about 65 percent, often dropping you a whole generator size.

With one fitted, a small 2,000 to 2,200 watt inverter generator can run a single 13,500 BTU air conditioner that it otherwise could not start.

Source: Micro-Air EasyStart; SoftStartRV. Run it: Generator Sizing Calculator →

The furnace, not the stove, empties your propane tank: a 20 lb tank lasts an RV furnace only about 3.6 days at 4 hours a night.

A 20 lb tank holds about 430,000 BTU. A furnace burning 30,000 BTU an hour for 4 effective hours uses 120,000 BTU a day, and that shrinks fast as the nights get colder and the furnace cycles more.

Source: Computed by the Propane Tank Runtime Calculator. Run it: Propane Tank Runtime Calculator →

A generator run too close to an enclosed space can kill within minutes: carbon monoxide causes about 100 portable-generator deaths a year in the US.

Run a generator outdoors only, at least 20 feet from any door, window, or vent, even with them open. For powering an enclosed space you sleep in, a battery power station is the safe choice because it has no engine and no exhaust.

Source: US Consumer Product Safety Commission (CPSC). Run it: Generator Sizing Calculator →

Internet, data, and power on the road

Your 'unlimited' plan caps hotspot data, usually at 30 to 100 GB, then throttles it; a typical remote worker uses about 110 GB a month.

Almost every unlimited phone plan is unlimited on the phone but caps high-speed hotspot or tethering separately. The number that actually decides your plan is the hotspot allowance, not the word unlimited on the box.

Source: Carrier hotspot pages; computed by the Mobile Data Usage Calculator. Run it: Mobile Data Usage Calculator →

Upload speed, not download, is what breaks video calls on a hotspot or Starlink: Zoom needs more upload than download at 1080p (3.8 up versus 3.0 down).

Connections are asymmetric, with far less upload than download, and Starlink's median upload is only about 19 Mbps. A link that streams 4K flawlessly can still stutter on a call because upload and latency, not the headline download number, are the limit.

Source: Zoom system requirements; Ookla; computed by the Internet Speed Calculator. Run it: Internet Speed Calculator →

The airline carry-on limit for a power bank is 100 watt-hours, and the real capacity is mAh times 3.7 volts, not the 5 volt output.

A 20,000 mAh bank is about 74 watt-hours, comfortably flight-legal. Calculating at the 5 volt USB output instead would wrongly show 100 watt-hours, overstating it by about a third and possibly flagging a legal bank as banned.

Source: FAA PackSafe and IATA rules; computed by the Power Bank & Watt-Hour Calculator. Run it: Power Bank & Watt-Hour Calculator →

On the water

Anchor rode is measured from depth plus bow height plus tide, not just depth: 15 feet of water can mean 22 feet of effective depth.

Add a 4 foot bow roller height and a 3 foot tidal range to 15 feet of water and you are scoping off 22 feet, so a 5:1 all-chain scope is about 110 feet of rode, not 75. Anchoring off the water depth alone is how boats drag.

Source: Computed by the Anchor Size & Scope Calculator. Run it: Anchor Size & Scope Calculator →

Over distance, wire gauge is set by voltage drop, not amperage: a 20 amp load over a 30 foot round trip needs 6 AWG, not the 12 AWG the ampacity chart allows.

A static ampacity chart cannot see the run length, which is exactly how short, thin runs get undersized and lose voltage. The longer the run, the thicker the wire, regardless of the current.

Source: ABYC E-11 and NEC voltage-drop method; computed by the Marine and RV Wire-Gauge Calculators. Run it: Marine DC Wire-Gauge Calculator →

A boat's solar array gets a harsher 0.7 derate than a home roof's 0.75, because the rig, boom, and bimini shade it.

Shading from rigging means a marine array delivers less than a land install of the same wattage, so a cruising sailboat drawing 60 amp-hours a day still needs roughly 260 watts of panel and a 240 Ah bank.

Source: Computed by the Sailboat Battery Bank & Solar Calculator. Run it: Sailboat Battery & Solar Calculator →

How we got these numbers

Each figure above is computed by one of our 14 free calculators, using the same published, primary-source data the tools cite: NREL solar-radiation data, the FCC broadband benchmarks and Zoom's recommended bandwidth, US Coast Guard equipment rules and CPSC carbon-monoxide guidance, ABYC marine wiring standards, the FAA and IATA airline battery limits, Battery University on lead-acid versus lithium, and manufacturer wattage charts from Honda, Champion, and others.

These are clear-sky, typical-case estimates, not guarantees. Real output depends on your equipment, location, and weather. Every fact links to the calculator that produces it, so you can plug in your own setup and get your own number.

Run your own numbers

All 14 calculators are free, with no signup. Start with the full tools hub, or read the build guides for the gear behind the numbers: the RV gear guide, the boat gear guide, and the work-from-anywhere guide. New to the road? See what a build and a month on it actually cost in the real cost of van life.

How we are paid: the gear guides contain affiliate links, and if you buy through them we earn a commission at no extra cost to you. It does not change what we recommend, and the calculators stay free either way.

Cite this study or use the data

The full dataset is free to reuse under a CC BY 4.0 license: quote a figure, chart the numbers, or download the raw data. All we ask is a credit link back to this page.

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Cite it

Sorted Gear. (2026). Off-Grid by the Numbers: Van, RV & Boat Living in 14 Facts (2026). Retrieved from https://sortedgear.com/off-grid-by-the-numbers/

Link to it

<a href="https://sortedgear.com/off-grid-by-the-numbers/">Off-Grid by the Numbers: Van, RV & Boat Living in 14 Facts (2026)</a>, a data study by Sorted Gear

Common questions

Where do these numbers come from?

Every figure is computed from one of Sorted Gear's free calculators using the same published, primary-source figures the tools cite, including NREL solar data, the FCC and Zoom bandwidth specs, US Coast Guard and CPSC safety guidance, ABYC marine wiring standards, and manufacturer wattage charts. Each fact links to the calculator that produces it, so you can run your own setup. These are clear-sky and typical-case estimates, not guarantees; your real numbers depend on your equipment, location, and weather.

What is the single most expensive mistake people make powering a van, RV, or boat?

Undersizing for the worst case instead of the average. A flat solar panel that loses half its output in midwinter, a generator sized to running watts that cannot start the air conditioner, and a battery bank sized to average rather than peak draw all fail at the exact moment you need them most. The fix in every case is to size for your hardest day, not your typical one, which is what each calculator does.

Is lithium really worth it over lead-acid for an off-grid battery bank?

Usually yes, because the usable capacity gap is larger than the price gap suggests. A 100 Ah lead-acid battery gives about 50 usable amp-hours, while 100 Ah of lithium gives about 80, so you need far less rated lithium capacity for the same real-world runtime. Lithium also holds its capacity under heavy inverter loads, lasts more cycles, and weighs less, which matters in a weight-limited rig.

How much solar do I actually need for van or RV life?

For a typical full-time setup drawing around 78 amp-hours a day, roughly 300 watts of solar paired with a 200 to 300 Ah lithium bank covers it, sized to your worst travel month rather than the annual average. The exact number depends on your fridge, your latitude, and how many cloudy days you want to ride out, which is what the RV Solar & Battery Calculator works out from your own loads.

Why does my Starlink or hotspot struggle with video calls even though the speed test looks fine?

Because a speed test mostly reports download, while video calls are limited by upload and latency. Connections are asymmetric, with much less upload than download, and a call needs to send your camera feed in real time. Starlink's median upload is only about 19 Mbps and a hotspot can be lower, so the upload, not the headline download number, is what runs out first.