How do I connect a trickle charger to my 2022 e-Boxer XV to ensure restart after a period of low usage?

There are two 12v batteries under the bonnet and the one described as for engine re-start has a warning notice on its terminals Not To Connect A Boost Charge.

The other is described as for ancillaries.

I have always connected a trickle charger on my 2019 XV and 2016 Levorg after flat batteries prevented restart.

Subaru customer support advise to connect trickle charger directly to auxiliary battery terminals. The aux battery is the larger of the two 12v batteries in the engine compartment, on the near side of the vehicle.

Avoid connecting to the other threaded studs also attaching cables to the positive terminal and which are protected by fuses.

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