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ARCHITECTURE GUIDE

AC vs DC batteries: which architecture to choose

A practical guide to choosing between AC- and DC-coupled storage for self-consumption, retrofit, backup and C&I projects.

The difference is where the battery connects

In a DC architecture, PV and battery share the DC side of a hybrid inverter. In an AC architecture, storage has its own conversion stage and coordinates with generation through the internal AC network and metering system.

DC coupling

Integration from the design stage

  • Particularly suitable for new installations with a hybrid inverter.
  • PV energy can be stored before conversion to AC.
  • Power and compatibility are tied to the hybrid inverter.
AC coupling

Retrofit flexibility

  • Allows existing PV inverters to be retained.
  • Makes it easier to separate charge power and battery capacity.
  • Adds conversion stages and requires correctly configured metering.

Advantages and limits by scenario

Criterion
DC
AC
New installation
Often simplifies a hybrid system designed from scratch.
Also viable, especially when independence between subsystems is desired.
Retrofit
May require replacing or complementing the existing inverter.
Often the most direct option for retaining the installation.
Efficiency
Can reduce conversions when charging from PV, but depends on equipment and operation.
May add an extra conversion; it must be assessed using real curves and efficiencies.
Scalability
Limited by hybrid inverter inputs, power and compatibility.
Allows storage blocks to be added with greater independence.

How to decide using real data

  • Does the PV installation already exist and need to be retained?
  • What power must the battery charge, discharge or back up?
  • Is there zero export, a generator, microgrid or critical loads?
  • Are PV or storage expansions planned?
  • What losses, costs and maintenance does each alternative involve?

Compare AC and DC for your project

We model power, capacity, shifted energy, backup and constraints before selecting equipment.

Request an architecture study

Author: Arturo Andrés · Technical review: Plug & Play Energy storage team · 17/08/2026.

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