There is also the current shunt resistor inside that needs to stay put. That is where the current is going through, the small leads is only measuring the voltage over the shunt resistor

Got it, I thought people were getting rid of the fuse circuit and soldering the connector directly into the red/black wire, just keeping the shunt resistor connected between positive and negative. That way you wouldn't need a fuse to make it work.

Is there a specific size of fuse I should use? Or a 30A will be fine?

Not only this will help measure current draw with the drive train friction, but also you can remove the pinion and test the amp draw free of load directly on the chassis, so you can test different amp draws without desoldering

No need to use a fuse, unless you are planning to go far beyond the 30A

Use a 30 amp fuse that way you have a safety factor in your circuit

I never tried it but I don't think it would work without the fuse.

Explain why you would think that. A fuse is noting more than a wire that melts away when more current is going through it than specified. No fuse will work also but with a shortcut wires will glow up but then again, in a car you do not use a fuse either.....

You would need the fuse to complete the circuit. That's why when a fuse blows, the circuit is broken. I'll have to try it sometime.

Would you mind explaining? Seems like the negative leg of the fuse tester is not connected, unless you put a fuse in there

Ah, I thought you was speaking of the use of a fuse in any type circuit, yes for that divice you need a fuse. 30A or larger will be OK.

This piece is what I was referring to. Now that we're on the same page. -)

Perfect, thank you!
Just had one last question, can I desolder at the fuse plates (where the purple arrows are pointing at) and just solder a piece of 12awg wire with the male/female bullet?
that way I can ditch that whole grey fuse connector and the fuse circuit, for a clean look.

Thanks again

Then you have no protection of your unit. Your still gonna have another wire coming out the side so looking cleaner...not really. This is not for concours btw. -)