Don't know the exact amp draw of the thruster. Round trip the wire run is 10 to 12 feet. 1/0 is quit bigger than what is already there so I think it will work but I am curious to measure its amp draw so I know.
Thank you very much for your input.
To add about the splitter, it will be temporary as I plan to improve that part later on with something more "efficient". Let say I am going step by step (or $ by $ lol).
When I installed my stern thruster I used 4/0 battery cable. My run is about 7 feet round trip. I want every bit of voltage I can get since the thruster draws so much current. Side Power does not even list 1/0 cable in my thruster manual. Maybe your thruster draws a lot less than mine, but larger cables are not significantly more money in the scheme of thrusters.
Sure, you can get an inductive amp meter & put it around the wire, trigger the Thruster on & read that amperage - but that does not tell you if the wire is to small - only tells you what amperage can squeeze through the little 1/0 cable - which is way to small for a thruster.
The actual key item to measure is the "voltage drop" across the in question cable under the load of applied power & load.
Anything over a half a volt voltage drop for that one cable means the cable is to small !
Connect your Fluke 87 digital Volt meter to each end of the cable in question & then have someone else apply the thruster to the on position & ready the voltage drop on your digital volt meter.
That is the definitive way to know what is going on.