Any tax credit to install a charger in 2018?

Who knows. There wasn't a plan for continuing the credit into 2017 after it expired at the end of 2016. Then just lately, Congress brought the credit back retroactively in a bargaining session, covering 2017. Bad planning on the government's part. Games like that can mess up plans. You never know. Install what you want, and keep all of your receipts in case you're asked for paper records - especially from an electrician spelling out what was installed and what it was for. Really needs to be spelled out definitively.