Howdy electronics fans,
I'm in the process of sorting out my starter issue by installing a relay to operate the solenoid. However, I've heard that the same issue that can damage the starter switch contacts can also damage the relay contacts over time - the reverse current spike from the solenoid when it switches off and the field collapses. This can be a couple of hundred volts.
I've Googled for a while and come up with a solution called a freewheeling diode, which from the info I have is connected in parallel with the load (solenoid or other inductive load). This apparently causes the spike to circulate through the field coil/diode circuit until it dissipates via heat in the coil.
However, my meagre electronics knowledge tells me that this would make the normal operating current go straight to earth, as the diode is installed + to - across the terminals. Should it be reversed, maybe?
What am I missing? Any ideas?