Even if it is the portable charger failing I would have your outlet verified and also make sure your wiring is 6 gauge. These are extremely important and could cost you your house if not installed properly. Just make sure who ever works on it is licensed because if something were to fail your...
They commented and said it would suck to have to pay another $800 16 months later. Why are you arguing this? Go read the thread yourself before making ridiculous comments.
The battery you already replaced also comes with a 24 month warranty. Be ready to pull out your invoice from the job cause some SC’s like to fight it.