EF ECOFLOW DELTA Pro 3 Portable Power Station, 4096Wh, 4000W AC Output | LFP Battery, Expandable to 48kWh, 120/240V, Solar Generator for Home Use, Camping Accessories, Emergencies, Power Outages, RV

Why it's worth it

The DELTA Pro 3 is a 4,096Wh battery with a 4,000-watt inverter, 120/240V output and no exhaust at all. You can run it in a bedroom next to a CPAP machine, and it takes over in about ten milliseconds when the grid drops.

No fuel means no carbon monoxide, and that changes where you're allowed to put it. Every gas generator on this page has to sit well outside, away from windows and doors, in whatever weather caused the outage. This one sits in the hallway. EcoFlow rates it as low as 30 dB, quiet enough to sleep beside. If someone in your house runs oxygen equipment or keeps refrigerated medication, that settles it.

The switchover is the other reason to want it. Ten milliseconds is fast enough that a desktop, a router, a NAS or a CPAP never registers that the grid went away. Put your essential circuit behind it and outages stop being events you scramble for. You get a notification on your phone and keep working.

From our review of 8 portable generators for power outages

What we like

• +No fuel means no carbon monoxide, and that changes where you're allowed to put it
• +The switchover is the other reason to want it
• +Capacity used to be where batteries lost, and this one pushes back hard
• +The cells are LFP in an IP65-rated pack, which is the chemistry you want in something that sits near full charge for months…

What to know

• –A battery only holds what you put into it
• –It's expensive, more than most of the gas generators here, and it weighs 115 pounds