Understanding weekend cabin sizing
The direct answer for a typical weekend cabin
A cabin using 1,800Wh a day with 4.5 peak sun hours needs about 500 watts of panel and roughly 280Ah of battery for a typical weekend, assuming a 1 to 1.5 day cloudy buffer during the stay. That system recharges the weekend's battery use in about 1.5 days of sun, leaving several days of margin before a typical every-other-weekend visit. For the official wording, see the NREL's PVWatts solar production calculator.
Why the recharge window matters more here than for seasonal cabins
A cabin visited every 10 to 14 days has a much tighter recharge window than one visited every 3 to 4 weeks, so it's worth explicitly checking whether the panels can keep up. If your recharge window check comes back tight or insufficient, either the panel wattage is too small for how often you visit, or the visit gap is too short for the system as sized. Both are fixable, but it's better to know before you arrive to a dead battery. For the official wording, see the Department of Energy's homeowner's guide to going solar.
Why weekend loads often run higher than seasonal loads
A cabin visited for a full weekend tends to see heavier use per day than one visited for a longer, more relaxed seasonal stay, since weekend visitors often pack cooking, showering, and entertainment into a compressed window. Don't assume a weekend cabin automatically needs a smaller system than a seasonal one; run the actual numbers with the load list builder rather than guessing based on trip length alone.
Keeping the system simple on purpose
A weekend cabin benefits from a system that just works without daily monitoring, since nobody is checking battery voltage from home during the week. Oversizing the battery slightly beyond the bare minimum, and choosing LFP for its tolerance of sitting at a full charge between visits, both reduce the odds of ever arriving to a problem. The battery lifespan estimator in our maintenance and lifespan tools is worth a look here too, since infrequent, uneven use ages a battery differently than steady daily cycling.
What to check once you have a system size
With the wattage and battery numbers settled, use the charge controller sizing tool to match a controller to your array, and compare against the seasonal use sizing tool if your visit pattern varies throughout the year. The weekend-specific math here differs enough from a general estimate that the battery size quick estimator in our battery storage tools is worth a second opinion against. Production estimates throughout draw on NREL's PVWatts solar production calculator, and the Department of Energy's homeowner's guide to going solar covers general system planning if this is your first build. A second sizing method is worth the check. The quick 5-minute system size estimator in our System Sizing section can help you confirm the panel count from your daily load.