@Elco I have a BrewPi Photon (v2) and was wondering if it is possible to power it through the RJ12 connector (by feeding it 12V). My BrewPi will be on the outside of my control box when used for mashing so I would like to have just one cable coming from the control box to the BrewPi. I know on the v3 you can switch the 12V to the RJ12 connectors but I’m hoping for the v2 the 12V is directly connected to the rail internally.
Inside my control box is an E-stop button, RCDB, 12V supply for BrewPi, 24V supply for pump and SSR for heading element (and DS2413 to drive it). Pretty simple really. Temperature sensors will be plugged in to BrewPi external to control box.
Yes this should be possible. The plug and the 12V out on RJ12 are directly connected through a 1.5A polyfuse. This fuse prevents drawing too much power from the RJ12 socket, but shouldn’t be in the way of what you want.
Thanks @Elco that’s good to hear.
Is this the same for BrewPi Spark V3? I remember you writing when you were developing the V3 you were going to have the option of toggling the 5V and 12V on RJ12 connectors. Is that still the case? If so would you be able to share the schematic so I can see what to bypass (or let me know the designator for the switching component)?
Yes, the V3 has mosfets to turn the power on the RJ12 connectors on and off. It is hardcoded turned on now, but will later get software support for power cycling peripherals. So I don’t recommend powering from the RJ12 connectors.
Does each connector have a separate FET? I’ll remove one and bypass it. I’ve already wired my control box and dont want to drill any more holes.
No, it is a single fet for all.
The 12V input also has overvoltage and emi protection. A better approach would be to split 12v off from your cable going in and route that to the barrel jack input.