So, a thing that will make or break this project, will be the connectors that feed power in and out.
My existing system uses the larger 50A Anderson connectors. These are big and chunky, not really appropriate for a PCB. The 30A version would be okay size-wise, and I use these on the bike, but 30A isn’t sufficient. That’s about my cluster’s peak current draw, and I want a 50% safety margin.
Thinking about it last night… 20V at 50A… that’s a kilowatt! Pales into insignificance when you compare it to the 48V 400A electric harvester I worked on years ago (and blew many a MOSFET on, not to mention boiling electrolytics with ripple current), but it’s still a decent amount of power.
There’s the XT60 and Deans connectors, however the problem with these is they aren’t all made equal, there’s some slight variances in the tolerances, thus you can buy two “XT60″s or two “Deans” connectors and find they won’t mate.
I see no problem in a short flying lead that connects to screw terminals. Take the flying lead, wire it up, then connect it to the connector of your choice. That’s how the solar controller I was using connected up, and I don’t think its problems were with its connectors.
The conductors I’m using are 6-8AWG. Whatever I use, must be able to handle that. There isn’t a lot out there for off-board connectors, and even the XT60s are a wee bit small. I did find these terminal blocks . Supposedly good for 76A, that’s enough safety margin for me, and Phoenix Contact aren’t known for producing crap.
The spade lugs used on the HEP-600C I’m using for charging my batteries would be smaller than this, and so far I’ve not seen any fires.
I might be able to put a few different footprints down on the PCB, we’ll see. I plan to design the PCB so there’s nice wide areas so you can drill your own hole and solder whatever you like there. Likewise for the inductor and capacitors, this will be a board that aims for flexibility.