For maybe 5 years or so, the maximum expiry time for a TLS cert (for anything under the purview of the Certification Authority Browser Forum) has been just under 400 days.

That's also not a hard technical limit in the TLS spec, you can easily generate a self signed cert that expires in the year 3000 if you want, but it's voluntarily abided by from all the Certificate Authorities that want to have their root certs included in almost every web browser. It's _possible_ that EV chargers don't use common Certificate Authorities, but it feels unlikely to me.