Solar + EV integration
How many panels does your commute actually need? Add your daily distance and vehicle efficiency for an instant count, plus a comparison table across common mileages.
How it works
Step 1
Use your average, not your longest day. If your driving varies a lot day to day, the EV charging load addition calculator handles weekly averaging directly.
Step 2
Efficiency varies a lot by vehicle class, so check your specific model on fueleconomy.gov rather than guessing.
Step 3
The built-in table shows panel counts across common commute distances, so you can see how your number compares without re-running the calculator.
Because energy need scales directly with miles driven and your vehicle's EPA efficiency rating, doubling your daily distance roughly doubles the panels required, all else equal. The one wrinkle is that panel counts round up to whole panels, so a very short commute sometimes needs an extra panel it wouldn't need if fractional panels existed, which can make low-mileage comparisons look slightly less proportional than the underlying math actually is.
Unlike the EV charging load addition calculator, which spreads your weekly driving pattern across 7 days, this tool takes your daily mileage figure and applies it directly, every day. That makes it a faster way to get a ballpark number, similar in spirit to the quick 5 minute system size estimator, but less precise for drivers who only commute 4 or 5 days a week. If you skip driving on weekends, divide your weekly total by 7 before entering it here, or use the load addition calculator instead.
Seeing your number next to nearby mileage figures helps you sanity-check the result and understand how sensitive your panel need is to changes in daily driving, like a new job with a longer commute or switching to a less efficient vehicle. A jump from 30 to 50 miles a day typically adds 3 to 4 extra panels, which is useful to know before committing to a system size.
Two drivers with an identical 30-mile commute can land on noticeably different panel counts if one lives somewhere with 5.5 peak sun hours, a figure NREL's PVWatts calculates by location, and the other gets closer to 4, since fewer sun hours means each panel produces less usable energy per day. This is why the sun hours field matters as much as the mileage field, and why a national average figure can throw off the result for anyone outside the middle of that range.
Night charging needs stored power. The battery storage size calculator in our Battery & Storage section can help you size a battery for the miles you drive each day. If you're also weighing a second vehicle, the two EV household solar sizing calculator handles combined driving totals directly.
Questions
For a typical efficient EV at 25 kWh per 100 miles with 400-watt panels and 5 peak sun hours, each 10 miles of daily driving adds about 2 extra panels, or roughly 0.8 kW of system size. This scales linearly, so 50 miles a day needs about 9 to 10 panels.
This calculator uses the daily mileage you enter directly, without averaging across a full week. For a more precise result that accounts for days you don't drive, use the EV charging load addition calculator instead, which factors in your actual weekly driving pattern.
Panel output doesn't divide evenly into whole panels, so rounding up to the next full panel affects lower mileages proportionally more than higher ones. The underlying energy relationship is still linear, but the displayed panel count can look slightly non-proportional due to rounding.
Use your typical average daily distance, not your longest single day, since solar sizing is meant to cover ongoing energy needs rather than occasional peak demand. Occasional longer trips are usually covered by grid charging or a battery buffer rather than oversizing the whole array.
Related tools