How Long Does a 768 Wh Power Station Last?

By our math, a 768 Wh power station runs a fridge for about 5.4 hours, a CPAP for about 16 hours, and Wi-Fi plus phones for about 19 hours. The 768 Wh box we list gives 800 W, so by our math it is not a box for a microwave, a space heater or a window AC.

The box we list at this size is the EcoFlow RIVER 2 Pro. Below: hour counts, mixes of devices, and when a bigger or smaller box fits better. To try your own list, use Find My Power.

Three words first

• Watt-hours: how much power a box holds. A 768 Wh box holds 768 watt-hours.
• Watts: how fast something uses power. We count a Wi-Fi router at about 15 watts and a microwave at about 1,100.
• Surge: a short burst some things need to start, like a fridge motor.

New to this? Start with What is a watt-hour?

How long does a 768Wh power station last?

The math we use across the site:

Hours = watt-hours × 0.85 ÷ watts

We keep 85% of the watt-hours because some power is lost on the way out. So a 768 Wh box gives your things about 653 watt-hours.

One thing at a time, from a full box:

Device	Watts we count	About how long on 768 Wh
Wi-Fi router	15 W	44 hours
Phones	20 W	33 hours
CPAP machine (humidifier off or low)	40 W	16 hours
Lights	40 W	16 hours
Fan	50 W	13 hours
Laptop	65 W	10 hours
TV	100 W	6.5 hours
Refrigerator	120 W	5.4 hours

Estimates. Your devices may use more or less.

We count a fridge at 120 watts across the site. More on that in how long a power station runs a fridge.

Running several things together

Add up the watts, then use the same formula:

What is plugged in	Total watts	About how long on 768 Wh
Wi-Fi + phones	35 W	19 hours
Wi-Fi + phones + lights	75 W	8.7 hours
CPAP + Wi-Fi + phones	75 W	8.7 hours
Laptop + Wi-Fi	80 W	8.2 hours
TV + Wi-Fi	115 W	5.7 hours
Fridge + Wi-Fi + phones	155 W	4.2 hours

Estimates. Your devices may use more or less.

So a 768 Wh box gets a CPAP, the router and your phones through one night of about 8 hours. It does not get a fridge through a whole day. For the CPAP side, see CPAP backup power for outages, and always check the watts with your machine's maker or your equipment provider.

What 800 watts rules out

Watt-hours tell you how long. Watts tell you what. The RIVER 2 Pro gives up to 800 W. By our math, anything that needs more than that is not a job for it:

• Microwave: we count about 1,100 watts. Too much.
• Space heater: we count about 1,500 watts. Too much. See can a power station run a space heater.
• Window AC: we count about 900 watts. Too much.

One catch. EcoFlow's RIVER 2 Pro page says a mode called X-Boost lets the RIVER 2 Pro power things like a hair dryer or a microwave at up to 1,600 watts. We don't count on it: our math uses the 800 watts in EcoFlow's spec table.

The fridge is fine on watts. To start, we count a burst of about 1,200 watts for a fridge. EcoFlow's spec table lists the RIVER 2 Pro's surge at 1,600 watts, so by our math it can start one, even with Wi-Fi and phones already on. Two notes from EcoFlow's manual: one line in it gives 500 watts and a 1,000-watt peak instead, and when the box sits between the wall and your things as a backup, the manual says to power one thing at a time, of up to 1,000 watts. We go by EcoFlow's page and spec table. If you plan that backup setup for a fridge, check with EcoFlow first: the 1,200 watts we count to start a fridge is above the manual's 1,000. More on the RIVER 2 Pro page.

768 Wh next to a smaller and a bigger box

Here is how the RIVER 2 Pro sits between the next EcoFlow box down and the next EcoFlow box up that we list:

Box	Watt-hours	Watts	Fridge	Wi-Fi + phones	CPAP
EcoFlow RIVER 2 Max 500	499 Wh	500 W	Does not start one, by our math	about 12 hours	about 11 hours
EcoFlow RIVER 2 Pro	768 Wh	800 W	about 5.4 hours	about 19 hours	about 16 hours
EcoFlow DELTA 3	1,024 Wh	1,800 W	about 7.3 hours	about 25 hours	about 22 hours

Estimates. Your devices may use more or less.

The RIVER 2 Max 500 lists a 1,000-watt surge, below the 1,200 watts we count to start a fridge. The DELTA 3 holds more and gives more watts, but EcoFlow lists it at 27.6 pounds against 18.2 for the RIVER 2 Pro. Other brands we list also make boxes of about 1,000 Wh; you can put any two side by side in Compare.

Who a 768 Wh box is for

• Yes: you want Wi-Fi, phones, lights and a CPAP through a night, or a fridge for a few hours. At 18.2 pounds, the RIVER 2 Pro is a box one person can carry.
• No: you want a fridge on through a long outage, or you need a microwave or heat. Look at boxes of about 2,000 Wh and up in Best Picks.

Questions people ask

Will a 768Wh power station run a fridge?

The RIVER 2 Pro can, by our math, for about 5.4 hours from a full box. Its 1,600-watt surge, as EcoFlow lists it, is above the 1,200 watts we count for a fridge to start. See the manual notes above.

How long will a 768Wh power station run a CPAP?

About 16 hours by our math, for a CPAP that uses about 40 watts with the humidifier off or low. A heated humidifier can use much more. Check the watts on your own machine.

Can a 768Wh power station run a microwave?

Not by our math. The RIVER 2 Pro gives up to 800 W, and we count a microwave at about 1,100. See the X-Boost note above.

How many amp-hours is 768Wh?

It depends on the volts. By our math, 768 watt-hours is about 64 amp-hours at 12 volts. EcoFlow lists the RIVER 2 Pro at 40 amp-hours at 19.2 volts: the same power, counted another way. Our amp-hours guide explains why the volts matter.