have you looked at esp32? it has wifi, i added an temperatur sensor and a gps-receiver, i also want to add voltage measurment + relais to turn on/off stuff depending on batterie-level, projekt is on hold for the moment... need to earn the money i spent last year ...
No, I haven't. I'm a bit of an EFM32 fanboy. I like the low power features, development tools, Linux support, and open source hardware/software. I have the comma.ai panda for reading data off the CAN bus through the ODB-II port on the van. That has the ESP8266 in it which is the predecessor to the ESP32. Sounds like a fun project. My victron charge controller has a built in load disconnect when the battery voltage drops too low so I don't need to build that. I'd like to add a CO and maybe gas sensor to the board if I ever get around to it. I hear ya on the money.
esp32 has a deep sleep mode, easy to use, works on my linux since it uses the arduino ide, but i didn't find a nice board, so a lot of soldering....
my victron solar charger also has that smart output, but my inverter pulls to much current for it...
if the battery gets to low the inverter switches off, but it makes that neverending beep sound, hope the new one is not so loud..
i really would like to be able to read my voltage over the internet, to get an alarm on the cellphone...
So you made a PCB? Ah, ya I'm only powering my laptop, phone, and at times LED lights/fan. I just have a cheap 175W inverter. That'd be cool. Are you going to have a separate cell radio hot spot in your van in addition to your phone then?
due to the wires i only go with 300W, bought a new one which has a batterie charger and networkswitchover included! for only 120€ => 130$
wifi depends on the country, i have an old router with openwrt running, i can connect it as client to any open wifi, it has a better range than cellphones/laptops, at the same time my private wifi is running on that router, where all my devices connect to, so when i come to a new location i only need to setup the new connection on my router. it works best with a router with 2.4ghz & 5ghz, openwrt doesn't support all 5ghz chips.
When i have no wifi I connect my devices manual to my phone, i use prepaid cellphone internet if i am in a country for a few weeks, in europe roaming is only free for short time travels. In sweden i got a free travelrouter with the simcard, but it only works with the swedisch sim card...