A smart electrical switch is going to destroy my home? Guess I've been living on borrowed time with my smart outlets.
Because yes, some homes are really vulnerable to electrical problems. And no, you can't trust any device (high-branded, non-name, DIY, whatever) on such homes. You can't even trust them to handle electricity being available, without any device consuming it.
A smart electrical switch toggling dozens of amps over several hours... this might be getting outside the realm of what I trust cheap chinese amazon products with fake, misleading, or no UL certifications to handle.
So like two microwaves. It's also not running 20 amps through the Arduino, if the switch the software is flipping is rated for that much power then it's fine.
People suspect the traditional duty cycle used in rating these has been more for dryers, kilns, or welders, where they're active for an hour tops or at least not drawing full current. An EVSE can be at full power much longer, making the rating... less reflective of real-world conditions. I've heard there's a new rating system coming out designed especially for EVSE-sized duty cycles.
And that's not even getting into things like torque specs for the connections, etc.
None of this is blocking a dedicated, well-researched, and properly equipped DIYer, but at this level of power, there's enough "tricks of the trade" involved where the risk-to-reward ratio falls maybe outside the casual "buy things off AliExpress and who cares if the magic smoke comes out" range.
At this current, spending an extra couple hundred bucks might be worth it to have an actual company with a non-made-up-syllables name and a non-Shanghai-alley address that my insurance company can go after if my garage goes up in flames because their UL claims were misleading.
You’re probably thinking about DC fast charging, where the charger is external to the car and connects directly to the battery. Nobody should be trying to make _that_ themselves with an Arduono, sure.
Getting the amperage wrong or sending power when the car is not ready both sound like astoundingly dangerous failure modes for a DIY project, even if the most damage is bricking your car's battery controller.
The EVSE is talking to the onboard charger, the on board charger is what actually interacts with the batteries. The EVSE has a specific resistance inline with a comm pin to indicate presence (even when unplugged from the wall) and modulates a frequency on the comm pin to indicate max amperage. The car puts a specific resistance on a different comm pin to request that the contactors close to connect the charger to wall power. Any problems or bugs thereafter are with the onboard charger, not the EVSE.
A 10A outdoor charger probably also deserves it's own breaker.
You have a good source for this? I see claims like this every time a discussion of this sort and they rarely come with any citations.
Insurance will pay out, provided electrical fires are covered by your policy.
They will then do their best to assign liability and pursue subrogation. If you did the work yourself, you're liable. If you're insured for that work, they'll come after your insurer. If you're not, they'll come after you. If your work is permitted and to code, you'll probably be fine, if not, good luck!
So it looks like you're correct! Unlicensed work appears to be covered, but you may paid AND sued.
If you are not comfortable with high voltage electrical work, or are not familiar with basic components of the electrical code that governs your area, then definitely don't do this. But mass-labeling the work of others as unsafe or harmful is not appropriate either.