energystack

Energy Stack / Battery storage

Layer 02 · Storage

Battery storage.

A battery is the most expensive single decision in the stack and the one with the slipperiest payback. Capacity matters less than the shape of your day.

11 guides 2 tools 14 articles

Guides

Sizing

How much battery do you actually need?

The wrong answer is "as much as you can afford". The right answer is your evening load shape.

Chemistry

LFP vs NMC, the short version

If the box is on a wall in your house, the answer is almost always LFP.

Hybrid

All-in-one hybrid inverters: pros and inconvenient cons

Tidy is not the same as reliable. What happens when one box has to do every job.

Payback

Working through a real payback, properly

Including the bits the brochures leave out: degradation, round-trip efficiency, opportunity cost.

VPP

Virtual power plants in 2026: who is paying what

Octopus Tesla Energy Plan, ev.energy and others. Which move the needle and which are press releases.

The featured essay

Long read · 14 min

Should you add a home battery to a small solar array?

A 4 kWp roof in Surrey, a 5 kWh battery and a year of half-hourly meter data. We ran the numbers four different ways and changed our mind twice.

Read the full essay →