I'm trying to control 6 normally-closed 230v valves using a raspberry pi. These valves draw little current when energised (1W) but do have a maximum inrush current of 550mA. Normally this would be easy -I'd just buy an opto-isolated relay module and be done with it. The problem is that these circuits are going to spend a lot of their time energised during certain parts of the year, and then nearly all their time off at other times. 6 x 70mA is nearly 0.5 amp of resting current on top of the 6W I'm already burning in the valves. Since I live off-grid, I'd like to save as much power as I can, both for those periods when the valves are mainly open and when their mainly closed.. Ideally, I'd also like to be able to power the control circuit directly from the Rapberry Pi, but I don't know if that's realistic - are there devices that can safely switch 230v with a 550mA inrush current that are low power enough to run directly from the RPI?
If I do have to use a relay, the good thing is that these circuits switch infrequently, and response time is not an issue. I guess I could use a bistable relay with some sort of control circuitry to generate pulses on the two inputs as the logic line transitions from 0V to 5V and vice-versa (do these exist pre-made?). But I'm hoping that maybe there's a low-power solid-state solution that will do this "in one"?