Missing Diode Module?!?
 

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.

I believe the module you are referring to is for the OBD test plug. Not needed to run/charge.
I am unsure how you can have 14v everywhere but the battery?? As obviously the battery in in series with the entire harness. How did you wire up your accessory? if you wired in straight to the battery there is most of your problem. Lithium batteries hate any sort of parasitic loss like those accessories. Wire it up so it is on a switched 12v circuit and make sure it is only powered when the bike is running. Give the battery a good charge and test again. The charging system on most dirt bikes is really only good enough to maintain a good charge, it won't recharge a very dead battery.

Thanks for the reply, Nate-
The diode module connector (connector "J" in the wiring diagram) is five pins, the OBD is a different one and four pins (not shown in the wiring diagram). The owner's manual shows them in different locations, and I just confirmed it on the bike-- the OBD reader connector is four pins, comes straight off and sits right next to the ECU, and it's taped up, also.
I did install the leads of the USB charger directly to the battery, just has I did three years ago on my CRF450x, which also has a lithium battery installed. The stator on the EC300 supposedly puts out 92 watts. Since my last two rides have been clearing trail, I've had my chainsaw mounted up front and the headlight removed-- so the stator has no other load on it, except for the rear light (very bright, even with a dead battery). Should be plenty to charge the battery.
I did put a good charge on the battery, and it is plenty to start the bike. But there is still no charge getting to the battery from the regulator. I believe the regulator is good, since, with the bike running, I'm getting 14+ volts measured at the headlight connector and at the taillight. Shouldn't I be able to disconnect the positive terminal from the battery with the bike running, and measure voltage at the battery cables?

Your bike doesn't need the battery to run.

Never disconnect the battery cables while the bike is running. Major no no. You can damage most of the bikes electrics doing so. It sounds like your bike is charging perfectly fine and it is just a mistake in the way you are testing. Send me a link to the wiring diagram and I will have a look at the diode module.

Page 68 in the factory service manual. It's item "K" (upper-right part of page). Mine is missing.

I am pretty sure that is the light relay. Do your lights work?

Hello...for me it wasnt as a lot of an issue. I am not knowledgeable about flying two strokes but rather I am pretty knowledgeable about 4 strokes which are entirely extraordinary and it was tossing for somewhat of a circle. A few side effects that would mean rich on a 4 stroke are like lean indications on a 2 stroke. That being said it didnt give me a lot of an issue figuring out how to comprehend the lectron. What I am anticipating doing after I get some additional time on the bicycle is tossing the PWK back in and getting it flown and contrasting the two with see which one I like.

pcb quote

Yes, what you refer to is the diode block. It is not a relay and as far as I know it has nothing to do with the lights.

The way you measure is wrong. You need the battery connected not disconnected to get a correct reading. Start the bike with a full battery, the OEM one should at least show 13.3 volts, even more if it was just fully charged. Start the bike, connect your voltmeter or multimeter to the battery poles. You may measure between 13 and 13.4 volts only when the bike is idling. Rev it and hold it at higher revs, the voltmeter should show at least 14 volts and a maximum of 14.7 volts.

If you measure always the same value and it does not change the battery wont be charged.

I know its an old thread but anyway.The Diode module is used to isolate and protect the two DC supplies ie The stator supply and the Battery supply.
The battery needs to be charged from the Stator.The Diode Module ensures the stator can only flow voltage into the Battery circuit but the battery cannot feed back into the Stator circuit (lights etc).
If you diode Module was missing your battery would not charge which is your Problem.
As for running the motor without the battery can destroy your electronics through over voltage.The battery is ,as well as being a load it acts like a regulator