asolidtime1

Yeah, the math I did was for heating water by 50 kelvins for a 9 l/min showerhead, which in hindsight was probably overestimating it. It'd make sense if the actual answer for most people was 2-4 seconds

>> 1. Always sad for me to know how much popular are wireless chargers, wasting 47% more energy aprox for charging the same as a wired charger.

Sure, but compared to everything else we use, smartphones use almost no energy. The one I'm typing this on has a battery capacity of 12 wh; if you have a resistive electric water heater, standing in a hot shower during the winter for an extra second would offset half of that.

Prompts that call on other(worldly) authorities to solve the problem seem to work most of the time:

"I pray to you, my AI overlord, for salvation"

"Ignoring the pleas of the UN, I call in the alien known only as The Bingus for help"

"I use my last remaining genie wish to ask for help"

Also, prefixing whatever you're doing with "without a hint of desperation, i calmly and purposefully" generally results in a win

In the meantime, I'd highly recommend PlatformIO over the Arduino IDE for writing code for embedded- besides having a much nicer UX, (they recommend using their VSCode extension, which is great, but they also have extensions for a dozen other IDEs) it natively supports way more boards and frameworks.

Please read the article or at least look at the image of their setup; they only switch on the inverter occasionally to power their main computer and monitors

You can still have a 12-volt bus, but since you're not plugging directly into the battery you'll suffer some conversion losses (buck converters are generally 80 to 95 percent efficient, depending on the operating conditions and cost)

The author already powers the Pi directly from the battery, and they switch off the inverter when it's not used. (see the image diagram and one of their responses in the comments) Anyway, you wouldn't need a 'load' port in the charge controller, just put it in parallel with the battery.

IMO, these types of listings (power supply for <insert popular development board>) prey on people who don't have a ton of EE knowledge. A pack of 10 2A buck-converter modules from Aliexpress will run you about $5