A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays.
General purpose RELAY DPDT 10A 230VAC RECT 8PL
PCB MOUNT MINIATURE RELAY, SPDT, 230VAC COIL, 16A CONTACTS, Ideal for solar DIY
RELAY SSR I=4-30VDC O=230V 25A
New Victron smart controller with Lithuim Ion Battery Control and remote cloud and data logging