Can a Wallbox charger be connected to a platform other than the manufacturer's?

Yes. The Pulsar Plus, Pulsar Max, Pulsar Pro, Commander 2, Copper SB models speak standard OCPP and let you change the server URL. In the my.wallbox.com portal (Chargers → Settings → Connectivity → OCPP → Edit) or in the myWallbox app (charger settings cog → OCPP).

Which OCPP URL do I enter on a Wallbox for askacharge.com?

wss://askacharge.com/askacharge/ocpp/your-brand, where your-brand is the brand identifier on askacharge.com; the charger appends its identity. The identity must match the one registered in the panel and the password stays blank unless the charger's OCPP credential has been enabled.

Do I lose the manufacturer's app when I set OCPP on a Wallbox?

Some app functions move to the OCPP platform (start, cards, statistics). The hardware stays the same and you can go back by changing the URL again.

How to change the OCPP server URL on a Wallbox charger (Pulsar Plus) and connect it to another platform

A Wallbox charger that speaks standard OCPP can be connected to any platform by changing one setting. Here is where that setting lives on Pulsar Plus, Pulsar Max, Pulsar Pro, Commander 2, Copper SB, exactly what to enter, and where people usually get stuck. Written by a platform (askacharge.com), but the procedure works for any.

Where the setting lives

In the my.wallbox.com portal (Chargers → Settings → Connectivity → OCPP → Edit) or in the myWallbox app (charger settings cog → OCPP).

Step by step

Update the charger firmware to the latest version from the app; older versions either hide the OCPP menu or fail to connect.
Make sure the charger has internet over Wi-Fi or Ethernet (Wallbox asks for at least −70 dBm of signal). Bluetooth is for configuring only, not for reaching the server.
Open my.wallbox.com → Chargers → your charger → Settings → Connectivity → OCPP → Edit.
In OCPP server URL enter your brand's URL on askacharge.com (below). In Charge point identity the identifier you registered; Wallbox suggests the serial number, which is a good choice.
Leave the password blank unless you enabled the charger's OCPP credential in the panel; if you did, enter exactly that password.
Accept the terms, save and switch OCPP on. The charger reboots by itself (1–3 minutes) and shows as connected in the panel.

What to enter to connect it to askacharge.com

OCPP server URL	`wss://askacharge.com/askacharge/ocpp/your-brand` — your-brand is your brand's identifier on askacharge.com (shown under Chargers → Add, with the full URL ready to copy). The charger appends its own identity; if your unit only has a URL field and no identity field, enter the full URL: `…/ocpp/your-brand/identity`.
Charge point identity	The same one you register in the panel when adding the charger. Case-sensitive. With Wallbox, the serial number is the easiest choice.
Password	Blank by default. If you enable the charger's OCPP credential in the panel (recommended for units exposed to the internet), the username is the identity and the password is the one the panel generates: OCPP Security Profile 2.
Protocol	OCPP 1.6J (JSON) or OCPP 2.0.1. Subprotocol `ocpp1.6` / `ocpp2.0.1`.
Before connecting	The charger must be registered in the brand with that identity; otherwise the server rejects the connection. Register under Chargers → Add.

Where it usually fails

With OCPP on, some myWallbox app features (statistics, control from the app) stop being available: they move to the platform. That is normal behaviour, not a fault.
On recent firmware, if it will not connect, try the URL without the wss:// prefix: some versions add it themselves and end up with it twice.
The charge point identity is case-sensitive and must match the registered one letter for letter.

If your brand isn't here

The procedure is always the same; what changes is where the setting lives: look in the manufacturer's app, in the charger's web interface (by its IP) or in the installer software for a section called OCPP, Back office, Central System or Server. You need to be able to enter the URL and, nearly always, the identity. If the field is locked or missing, the manufacturer has tied the charger to its own platform: read what to do when the manufacturer locks or switches off its server.

Other brands

AlfenEve Single S-line, Eve Single Pro-line, Eve Double Pro-line, Twin AutelMaxiCharger AC Lite, AC Wallbox, AC Elite, AC Ultra Grizzl-EGrizzl-E Smart, Grizzl-E Smart v2 (North America)V2CTrydan, Trydan Pro CircontroleNext Elite, eNext Park, Raption, Wallbox eHome (with communications module)

Sources

Wallbox Pulsar OCPP configuration guide (Enphase)

How to change the OCPP server URL on a Wallbox charger