Home Battery Backup Without Solar: What Refills It Matters More Than What It Holds

Almost every guide to home backup assumes you’re buying panels too. Most people aren’t, and for most outages they don’t need to.

Here’s the honest version: for an outage under 48 hours, solar contributes almost nothing. A charged battery covers it. Past 48 hours the question stops being how much does it hold and becomes how do I refill it — and that’s the question a no-solar plan has to answer before you buy anything.

What does a battery actually cover without solar?#

The loads that matter, for one to three days, depending on capacity.

An essentials-only household draws far less than people expect once you stop counting the things a portable power station was never going to run:

Load	Watts	Wh per day
Refrigerator (duty-cycled)	45 W running	~324 Wh
LED lighting, 4 rooms	30 W for 6 h	~180 Wh
Phones and laptops	—	~200 Wh
Router + modem	15 W	~360 Wh
CPAP, no humidifier	10–15 W	~100 Wh
Essentials total		~1,164 Wh

Call it 1,200–1,500 Wh a day with a margin for the things that always come up. Divide by 85% inverter efficiency — the figure the sizing calculator uses — and one day needs about 1,700 Wh of battery.

Coverage	Daily load	Battery needed	Class
1 day	1,400 Wh	1,647 Wh	2 kWh
2 days	2,800 Wh	3,294 Wh	3.6 kWh or expandable
3 days	4,200 Wh	4,941 Wh	Expandable platform only

Without solar, you buy that capacity up front. There’s no daily contribution making up the difference, which is why the no-solar decision is really a decision about how many days you’re planning for.

What refills it when the grid is down?#

This is the part that separates a plan from a purchase. Three options, in order of how well they work.

1. Grid power somewhere else#

The cheapest and most overlooked. Outages are usually local. A workplace, a relative’s house, a café, a library — anywhere still on the grid refills the unit at its full AC charge rate.

That rate matters more here than anywhere else in this category:

Model	Capacity	AC recharge
EcoFlow DELTA 3	1,024 Wh	56 min
EcoFlow DELTA 2 Max	2,048 Wh	78 min
BLUETTI AC200L	2,048 Wh	90 min
EcoFlow DELTA Pro	3,600 Wh	108 min

Under two hours to refill 3.6 kWh is the reason a fast charger is worth paying for in a no-solar plan. An hour parked somewhere with power buys you another day at home.

2. A vehicle#

Roughly 400–600 Wh per hour of engine running, and it costs fuel you may also need for driving.

Most power stations charge from a 12 V cigarette-lighter socket at 100–120 W, which is slow — a 2 kWh unit takes most of a day. Units that accept a higher-rate car charging cable do considerably better. Either way, run the engine; drawing from a parked car’s battery without it will strand you.

This is a top-up strategy, not a refill strategy. It buys hours, not days.

3. A gas generator#

The only option that genuinely solves multi-day outages without solar.

Run the generator for an hour or two a day to refill the battery, then shut it off and live off the battery in silence. You get the generator’s endurance without its noise, its exhaust, or the need to run it overnight.

This pairing is better than either device alone, and it’s covered properly in power station vs gas generator.

When does no-solar backup stop working?#

At about 48 hours, or the second consecutive day without a recharge opportunity.

The arithmetic is unavoidable. A 2 kWh unit covers roughly a day and a bit of essentials. A 3.6 kWh unit covers two and a half. Beyond that, capacity is a losing strategy — you’re buying an ever-larger battery to solve what is actually a refill problem.

If your area regularly loses power for more than two days, the honest recommendation is that you need a recharge source, and your choice is solar or a generator. Buying a bigger battery instead is the expensive way to be disappointed later.

If your outages are the more common kind — a few hours to a night, once or twice a year — a battery alone is genuinely the right answer, and the panels would spend their life in a cupboard.

The mistake that ruins the plan#

An empty battery.

A power station that self-discharges slowly in a closet for eight months is at 70% when the storm arrives, and 70% of your plan is not your plan.

Two habits fix it:

Charge to full whenever severe weather is forecast. With a 56–110 minute recharge, that’s a decision you can make the morning of.

Leave it in UPS pass-through mode if the unit supports it. The unit sits permanently plugged in with your fridge or CPAP plugged into it, stays topped up, and switches to battery in about 10 milliseconds when the grid drops — fast enough that nothing reboots. Our database lists this on the EcoFlow DELTA series and the BLUETTI AC series.

Pass-through is the single feature that most changes how well a no-solar plan works in practice, because it removes the human step entirely.

What order should you plug things in?#

Cold first, then communication, then comfort — and the order matters more without solar than with it, because nothing is coming back until the grid does.

1. The refrigerator. It’s the largest essential load and the one with a deadline: food safety, not convenience. It’s also the load with a startup surge, so plug it in before the battery is under load from everything else. Running a fridge in an outage works through the timings.
2. Medical equipment. A CPAP is small — about 100 Wh a night without the humidifier — but it’s the load you least want to discover you’ve run out of at 3 a.m. Reserve for it explicitly rather than assuming.
3. Router and modem. 15 W keeps you on the internet if your provider’s equipment is still powered, which is often how you find out when the grid is coming back.
4. Phones and laptops. Small, and they hold their own charge, so they can wait for a top-up window.
5. Lighting. Use battery lanterns first and save the power station for things that can’t run on AA cells.

What to leave unplugged: anything with a heating element. A kettle, a toaster, a microwave and a hair dryer draw 1,000–1,500 W each, and a single five-minute kettle cycle costs about 100 Wh — a whole night of CPAP therapy for one cup of tea. In a no-solar outage that trade is almost never worth it.

The fridge is the load worth checking your own figure for, because it varies more than any other. Old units draw considerably more than the 45 W running figure used above, and a full freezer holds temperature far longer than an empty one — which means you can cycle the fridge on and off rather than running it continuously, and stretch the same battery across an extra day.

What a portable battery will not do#

Worth stating plainly, because “whole house battery backup without solar” is a phrase people search and the honest answer is that it describes a different product.

These will not run: central air conditioning, an electric range or oven, an electric water heater, an electric dryer, or a well pump on most units. The limit is inverter output, not capacity — a 2,400 W inverter cannot start a 3,500 W load however many watt-hours sit behind it.

These are not wired into your house. A portable unit powers what you plug into it. Connecting one to your home’s circuits requires a professionally installed transfer switch or subpanel, and back-feeding a socket is dangerous to you and to line workers.

Whole-house backup without solar exists — it’s an installed home battery wired to your panel, typically 10–15 kWh, permitted and professionally fitted. That’s a different category at roughly ten times the price, and if that’s what you need, a portable power station is not a cheaper version of it. It’s a different thing that covers a different set of problems well.

What about calling it a solar generator?#

The same units are sold as solar generators when bundled with panels, and the battery inside is identical. Buying the bare power station without the panels is a legitimate choice — you can add panels later, since the charge controller is already built in.

If you think you might: check the unit’s maximum solar input before you buy, because that ceiling is fixed. The DELTA 3 accepts 500 W, the AC200L 1,200 W, the DELTA Pro 1,600 W. It costs nothing to have the headroom, and it’s the one no-solar decision that’s expensive to reverse.

Where to go next#

• Battery backup for power outages — planning the kit by outage length
• Best home battery backup — the picks, including when an installed system wins
• Run a fridge in an outage — the load that sets your deadline
• Power station vs gas generator — the pairing that solves multi-day outages
• Hurricane season checklist