Add up the night, then size the tank

A closed fridge is about 150 watts when the compressor is on, about a third of the hour. Tick the router, a CPAP, some lamps, or type your own watts. What you get back is average draw, watt-hours per day, and how many nights a 2,048 Wh tank lasts if you only spend 90 percent of the label. Pencil math. Nobody here metered your kitchen.

A kitchen during an outage, one lamp on, the refrigerator the load most people are adding up

Updated September 2, 2026

The short version

Default night is a closed fridge at about 150 watts, on about a third of the hour. Optional rows for a router at about 10 watts, a CPAP at about 50 watts, and lamps. Average watts times 24 is watt-hours per day. Nights are that daily spend against 2,048 watt-hours at 90 percent usable. A 1,500 watt heater is an evening, not a weekend. Arithmetic, not a hold. Prices checked September 2, 2026.

The longer fridge essay is how long a solar generator runs a refrigerator. The night itself, cords and all, is what a station really runs. This page is the adding machine.

The loads

Leave the fridge on. It is the reason most people are shopping. The other rows start off; tick them if they are on your must-list. Duty is the share of the hour the thing is actually drawing. A third is 33 percent here. Type a nameplate if you have one. These starting figures are planning numbers from the copy this site already uses, not a clamp-meter night in a particular house.

Average watts49.5 W
Watt-hours per day1,188 Wh
Nights on a 2,048 Wh tank1.6 nights

A 1,500 W heater is an evening, not a weekend.

Tank in this box is 2,048 Wh, the BLUETTI AC200L and Anker SOLIX C2000 Gen 2 nameplate. Usable here is 90 percent of that, 1,843 Wh, because LiFePO4 likes a margin and inverters skim a little. Jackery prints 2,042.8 Wh; same class, same rounding. Hours in a night, for this page, are 24.

What those three numbers are

Average watts. Running watts times duty. The fridge at 150 watts and 33 percent is about 50 watts. That is porch-light money. A router at 10 watts, always on, adds 10. A CPAP at 50 watts, left at 100 percent, adds 50; if it only runs the night, drop the duty toward a third. Lamps at 10 watts and 25 percent are a couple of evening LEDs, not a chandelier.

Watt-hours per day. Average watts times 24. The default fridge is 1,188 Wh. That is the spend. Open the door and you are not in this model anymore; the compressor stays on longer, and tomorrow’s hours move into tonight. The fridge-runtime page is the closed-door version of that story.

Nights on the tank. 2,048 Wh times 0.90, then divide by the daily spend. The 90 percent is the conservative cut this site already tells people to take: do not plan on the last drop of the label. Default fridge lands around a night and a half. The rounded “about two days” on the fridge page is the same arithmetic without that haircut, on a door that stays shut. Both can be true. Plan with this one.

The 1,500-watt problem

Resistance heat does not care that you also wanted the milk cold. 1,500 watts into a 2 kWh tank is an evening with a warm corner, then a dark one. Add a load, type 1,500, and the nights line will say so in hours. Wear the sweater. If heat is the job, this class was never the machine: standby generators or a home battery that can actually carry it.

The tank this math is for

Full SKU notes already exist. This is only the adding machine, pointed at the same three ~2 kWh 120-volt stations. Sticky on this page is the fridge-and-CPAP night: the BLUETTI AC200L.

$847 at BLUETTI, opens in a new tab

Price checked Sep 2, 2026

BLUETTI AC200L — 2,048 Wh, 2,400 W, 62.4 lb, $847 that day ($52 off $899), extra batteries printed to 8,192 Wh, still 120 volts. The sticky because the fridge night is its job, and the attic is there if the outage teaches you to want more hours. Shop: BLUETTI.
Anker SOLIX C2000 Gen 2 — same 2,048 Wh tank, 2,400 W continuous, 4,000 W peak printed, 41.7 lb, $949.99 that day ($50 off $999.99). The one you will actually carry to the kitchen. Anker SOLIX, not Anker.com retail. Shop: Anker SOLIX.
Jackery Explorer 2000 Plus — 2,042.8 Wh, 3,000 W continuous, 61.5 lb, $2,199 that day. The 2 kWh comparison band, not the default sticky. Standalone Explorer 2000 Plus Portable Power Station was not available on jackery.com on September 2, 2026; kits were still listed on that same page. Hop stays Jackery, brand-root.

Prices checked September 2, 2026 on the makers’ US pages. The family comparison is Jackery vs BLUETTI vs Anker SOLIX. Job-by-job picks: the stations we’d buy. Sizing lecture: the buying guide.

This calculator is your page if

You want hours from a list, not a slogan on a spec sheet.
The must-list is 120-volt: fridge, internet, lamps, maybe a CPAP.
You can skip the space heater, or you want the numbers to talk you out of it.

Skip this page if

The well, the dryer, or the air handler has a vote. That is 240 volts: F3800 or a standby generator.
You wanted a rooftop or a Powerwall. Out of scope: about.

Featured shops: BLUETTI, Anker SOLIX, Jackery. Same price to you if a commission is paid. Disclosure.

Nobody here metered your fridge, your CPAP, or your lamps. This is arithmetic on planning watts plus dated spec sheets. Check the live product page before you spend four figures. Method: how we work · corrections: contact.