Battery or no battery?

The problem a battery solves

Your panel makes its power in the middle of the day. Your household uses most of its power in the evening. And under SB 868, anything you produce and don't use is worth exactly nothing.

So on a sunny Tuesday in an empty flat, a 1,200-watt system might make 6 kilowatt-hours and give away 3 of them. Then at 7pm you come home and buy back electricity at 33 cents — or, if you're on a time-of-use plan in summer, closer to 58.

A battery sits between the panel and the outlet, absorbs the midday surplus, and releases it in the evening.

The numbers

Estimated at SCE's 33.2-cent average rate. Full working.

If you're on a time-of-use plan the case is stronger than that table shows, because the evening power you're displacing is the expensive kind. On SCE's TOU-D-4-9PM, summer weekday peak runs around 58 cents against roughly 24 cents off-peak. A battery that shifts 2 kilowatt-hours a day from midday to the peak window is worth substantially more than the blended-rate arithmetic suggests.

When to buy one

Yes, probably:

• The place is empty from morning to evening.
• Your bill is over $250 a month.
• You're on a time-of-use plan with a 4pm–9pm peak.
• You're already at or near 1,200 watts and want more return without more panels.
• You want the app and the data, and you'll enjoy it. This is a real reason and people are shy about it.

No, probably not:

• Someone's home most days already using what you make.
• This is your first kit and you're still finding out whether the balcony is any good.
• You care most about payback period.
• Your total budget is under $1,000 — spend it on panels and a tilt bracket instead.

What a battery does not do

It doesn't give you backup power. This is the one people get wrong. Plug-in solar devices are required to shut down when the grid goes out, and the battery in a grid-tied plug-in system shuts down with it. If you want the fridge running in a blackout, you want a portable power station with a backup output, which is a different product bought for a different reason.

Some products blur this line. Read the specification for the words "backup," "EPS," or "off-grid output," and if it isn't there, it doesn't do it.

It doesn't make you money. There's no export payment to arbitrage. A battery only ever saves you from buying, it never earns.

It doesn't last as long as the panel. Lithium-iron batteries in this class are typically rated for several thousand cycles, which at one cycle a day is a decade or so. Panels are warranted 25 years. Budget accordingly.

What the German market did

Germany is the only mature market for this category, so it's the only place to look for what buyers eventually conclude.

EcoFlow's own German sales data, shared with the trade press, shows the share of its balcony systems sold with storage doubled from 20 percent in 2023 to 40 percent in 2025. Buyers in a market with a decade of experience are increasingly choosing storage.

Two caveats before you read too much into that. German electricity is expensive but the rate structure differs from California's. And Germany's inverter cap is 800 watts against California's 1,200, so a German system exports proportionally more of what it makes — which strengthens the battery case there relative to here.

What we'd do

First kit, unsure about the balcony: no battery. Buy panels, buy a tilt bracket, buy a $25 plug-in energy meter, and find out what you've actually got.

Second purchase, a year in, with data: now you know your production curve and your household's habits. If you're exporting a lot, the battery has a real number attached to it rather than an assumption.

That sequencing costs nothing extra and turns a guess into a decision.

Kits with batteries → · What would yours save? →