Kona doesn't reliably charge - Europe

I have a 2021 Kona EV and ever since we bought it have had a problem. I've used a workaround until now, but (a) the workaround doesn't work anymore and (b) the workaround relies on bluelink which expires soon and I'd rather not subscribe. The dealer has so far been unsympathetic.

The problem is as follows. We have solar panels and charge the car in two ways: (a) during low tariffs from 2am-4am, and (b) from surplus solar at any time. This schedule is set on the charger (myenergi zappi) so basically I want the car to start charging whenever the zappi decides to deliver current.

However frequently, when ready to charge at 2am or from sunshine, the zappi changes it's status from "plugged in" to "waiting for EV", but charging does not start. At this point I can either hit "start charge" on the bluelink app, and it will start charging after 10-20 seconds. Or I can go out to the car, unlock, then lock again. Or refresh status in the app etc.

It's as though the car decides to go into sleep mode and stops responding to the charger which wants to supply current. I've set scheduled charging on the Kona from 2am-4am, but the problem still occurs.

Anyone else experienced this?

The workaround involves using a smart home setup (home assistant) with a plugin for Kia & Hyundai. An automation detects when the charger is ready to charge but not charging, and calls the start_charge function through the bluelink API. This plugin recently stopped working, but I can't rely on it anyway since my bluelink expires soon.

Thanks for any help.