Basically, what I have going on here is a giant "12V" UPS/Solar setup.
12V Battery bank as one input (solar charging is handled separately), 12V from a power supply.
I currently have two solid state relays driven by an esp8266 (and some other stuff) to select the battery bank until it gets down to 11.8V, then fire up the power supply. Once the batteries have recharged enough from the sun, switch back to battery. That part was easy. Keeps electric cost down a lot. Works great for all my unregulated 12V loads right now.
Now, to complicate things. I'm going to need 5V, 12V, and 48V outputs. The 12V probably should be an actual solid 12V (some sata hard drives...don't think those will enjoy swinging between 11-15v very much...raid arrays with very vital data).
My first thought was simply grab a buck converter for the 5V, and a boost converter for the 48V. Easy enough.
They seem to make auto buck/boost converters to make a stable 12V, but those are hard to find with 20A ratings. I could always boost to say 17, then buck down to 12...
To get an idea of power consumption here, I'd need 5V 25A, 12V 20A, 48V 2A, and probably 30A of 11-15V with no regulation.
Now, that wouldn't be so bad, until I realized a lot of those converters said you can't connect the input and output side grounds or the magic smoke will come out.
All these loads need to be switched individually. Things freeze up, and I currently have an RPi set to ping/ssh into everything to see if its alive. If not, I can just have it hard reboot. I was thinking MOSFETs since I have about 100 N-Channels and high side drivers laying around, and I'm trying to minimize current consumption (and physical size) of the controller here, or I'd just go for relays and this wouldn't be an issue.
Concerns: If the grounds of the converters can't be connected, I'd have to have separate power rails from there on out. That in itself isn't bad. High side switching is a must...very bad things happen if the ground is switched (things still stay powered via hdmi grounds, audio grounds, mains grounds, etc).
Thoughts: I could power the high side drivers off of each power rail, and optoisolate from the esp8266's i2c I/O expanders, but that's going to add a lot of components.
Suggestions?