Missing Diode Module?!?

[Mikie1]

Hi Gents-

Sorry in advance for the long-winded post...

I bought an '18 EC300 with 34 hours on the clock. Its only use was in the Chile ISDE. It has a much larger battery than stock (AntiGravity 240 CCA). I've only put about 15 hours on the bike since I bought it. The electric starter has always worked VERY well, until...

I installed this:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I've learned to unplug the converter at the SAE plug when not in use-- the USB converter does draw a tiny bit even with nothing plugged into it. I forgot to unplug it overnight, but the bike still started easily the next morning when I loaded up to go to Idaho.

In Idaho, the bike started sluggishly, then wouldn't start with the battery at all, and my phone stopped charging. Battery was dead. Bike started fine with the kicker and ran good. Chasing down the problem, we discovered that the bike wasn't charging the battery. Running, there's 14+ volts everywhere on the bike except to the battery. Starter relay and its fuse are good.

Once home, I discovered a wire with a five-pin female connector zip-tied to the starter relay rubber holder, but nothing plugged into it. The connector was wrapped with electrical tape. From the wiring diagram, it appears that a MODULO DIODO (diode module) is supposed to be plugged in there, but it's missing. I charged the battery, and the bike starts and runs perfectly, but if I disconnect the battery once the bike is running, the bike still runs, but there's no voltage at the battery cables.

Does anybody know what that module does? Would I get these symptoms with it removed? I ordered another one from MotoCenter (excellent service, BTW). Seems unlikely that it was missing when I bought the bike, and that the battery would have had enough juice to start the motor dozens and dozens of times. But, it also seems unlikely that the module would have just fallen off, given that the connector was wrapped with electrical tape. Guess I'll just have to wait 'til I get it to see if installing the new module solves the problem.

Comments and/ or suggestions appreciated.