Multiple central systems

Most installations need only one central system: a single OCPP entry listening on one port, with every charger connecting to it. Some setups need more than one — chargers on separate networks, or a charger whose firmware insists on a particular port. Each extra central system is simply another instance of the integration, added the same way as the first, on its own port.

This page covers what changes once a second one exists.

Identifying a charger in an action

Every OCPP action takes an optional devid:

- action: ocpp.set_charge_rate
  data:
    devid: garage_charger
    limit_amps: 16

devid accepts either identifier of a charger:

Identifier	Where it comes from	Unique?
cpid — the charger id you chose in Home Assistant	you, during configuration	yes, across every central system
cp_id — the OCPP identity the charger reports	the charger’s own settings	not guaranteed

The cpid is the one to use. Home Assistant keeps it unique across every charger of every central system, because your entity ids are built from it. A cp_id is whatever the charger was shipped with, so two chargers on two different central systems can easily both call themselves CP_1.

What happens with one central system

devid stays optional. An action that omits it is delivered to a charger of that central system, exactly as before, so existing automations written for a single charger keep working untouched.

What did change: a devid that is given but matches no charger now fails, where it used to fall through to a charger anyway. If an id in an automation went stale — after a rename or a re-pair — that automation was quietly acting on whichever charger came first, and now says so instead.

What happens with several

Actions are routed to the central system that owns the charger you named, so a charger on one system can no longer receive an action meant for another. Omitting devid stops working here, because there is no longer one obvious target:

A devid that matches one charger — delivered there. This is the normal case.
No devid — the action fails. Nothing is guessed across several systems.
A devid that matches nothing — the action fails with No charger found for device id …. Check it against the cpid on the charger’s device page.
A devid that matches a charger in more than one system — the action fails as ambiguous. This happens when two chargers share a cp_id; pass the cpid of the one you mean instead.

If you have automations that rely on omitting devid, add it before configuring a second central system.

Troubleshooting

“No charger found for device id …” — the id matches no charger, or no id was given and more than one central system is configured. Check it against the cpid shown in the charger’s device page. A charger that is configured but has never connected is not routable either.

“Charger id … is ambiguous” — two central systems each have a charger answering to that cp_id. Use the cpid, which is always unique. Alternatively give the chargers distinct OCPP identities in their own settings.

“Charger is currently unavailable” — the charger was found, but is not connected right now. This is about the connection, not the id.