Relays are simple and robust. Hit them with a voltage spike and they'll still survive. You'll have no commutation problems or holding current issues. Just put a little snubbing across the contacts to keep arcing at bay. In quite a few consumer goods you'll still find relays - for good reason.


I had a look at my old Motorola thyristor data book - something like a MAC228 series device has a holding current of 15mA. I'm not sure who makes them now -maybe onsemi? I gather you're not trying to phase control the solenoids - just turn them on or off, so the inductive load should not be a great issue - just have some snubbing across the device. In fact, if you know the specs of the device you're controlling, then formulating the snubber is much easier. If you want to have more holding current, just place a suitably sized resistor across the solenoid as a resistive snubber. Watch the power disipation though.