For power I order of amazon, some prewired 2.1 mm connectors, some cable and a 10A power supply. I put a female on one end and connect 6 male 2.1 mm connectors spaced along a cable.
DC 2.1 mm sockets and plugs (5A): https://www.amazon.c...uct/B0911TYJQC/
12V 21A cable (rated high to reduce voltage drops along cables) : https://www.amazon.c...duct/B07F6FBCZN
10A power supply: https://www.amazon.co.uk/gp/product/
This lead now powers my mount, focuser, filter wheel, dew heater, raspberry pi, asi cams and flats box.
For 5V devices (raspberry pi and USB hub for ASI cams) I took a project box and put 2 USB breakout boards and two 2.1 mm jacks holes in. One jack is 12V in, the other is 7.4 V out (cannon cameras). The USB voltage is set to 5.25V (allow for voltage drop along cables). There are three DC-DC buck converters inside that step down voltages.
USB Breakout board (solder across data pins to allow USB charging by phones etc.): https://www.ebay.co....tm/232686107596
DC-DC buck converters: https://www.amazon.c...e?ie=UTF8&psc=1