DC-DC converter died??

[Haplo]

The irony,.. after reviving the Brammo after a B40 error (see here: https://brammoforum.com/index.php?topic=4342.0) and riding it last week with good results, it's dead... again..

After communting last week the battery on the Empuls was left with 16% charge.. not much.. So I attached the charger and the lights died.. Not of the Brammo, but of my shed.. and house.. Something shorted, cause the 'earth leakage circuit breaker' of my house went out. After reinstalling, I went back to the Brammo. Now I could install the charge-plug without causing the lights go out, but the charger gives an error and the Brammo does nothing. The error of the chargers: the earth light and error light are blinking. Twice. The Brammo does nothing and therefore there is also no LOG in the USB-stick.

The Brammo kept working without problems. Started up like normal, still with 16% charge. I (again) took all the covering of the Brammo off, to check the fuses near the charge plug. No blown fuses there. All looks to be ok and I know I assembled it correct after my last project, cause I charged it without problems last weekend. Also the LOG of that charge does not show any issues.

However after some 30 minutes I tried the Brammo again, but now the Brammo also didn't start up anymore. Just nothing! Completely dead.

Could it be I fried the DC-DC converter?
I read the Charger has 3 fuses. Where are these located?
I would like to connect the white 2-pin 12v connector (similar to Tamiya battery connector) to see what this brings me, but both leads are white. What is positive and negative?
I tried searching the forum, and found a lot of info about the connector, but not the poliraty. I did find this post: https://brammoforum.com/index.php?topic=4342.0 Might be something to check. Or is there another suggestion?

[Korbin Dallas]

Under the charge port is a black fuse holder. Push the two ends towards each other and twist. There is a round fuse like an automotive glass fuse. It is 125v i think. Check it with a meter

[Korbin Dallas]

With the key on you can probe the back of the connection to the dc/dc converter on the two white wires and see if you have 12.5 volts. I had to take the tail light and pretty much the whole back of the bike apart to get the plastic cover off the bottom to expose the converter. It is down by the shock and on the left side

[Korbin Dallas]

https://youtube.com/shorts/rhbIeib9jiM?si=wNr-7Jxhf49jUaGe

[Haplo]

With the key on you can probe the back of the connection to the dc/dc converter on the two white wires and see if you have 12.5 volts. I had to take the tail light and pretty much the whole back of the bike apart to get the plastic cover off the bottom to expose the converter. It is down by the shock and on the left side

I already tried to measure the 12,5 volts. However, there is nothing there anymore. Key on or off.. Nothing. So also no way to tell - from +. If anyone can measure and tell me, that would be great. Thanks for the video! I assumed the dc-dc was part of the VCU, but good to know where it lives..

[Korbin Dallas]

I pulled that charge fuse out of my bike then turned on the key and it still showed 12.4 volts on the output of the dc/dc converter. So no help there.
 Try disconnecting the main power feed under the frame in the front and leave it off for a few minutes then plug it back in..(I.T. Have you restarted your device?)
Here is where I connected my meter to the dc\dc
https://youtu.be/arEYWODOQDM?si=Kjj_Y4kwWGfMac5l

[empulsefan]

Hello Haplo, you should measure over 80v on the 2 orange wires!

groet, Gerry

[Haplo]

Alright,.. update:

• Checked the single fuse in the black cilindrical housing: OK
  
• Checked the voltage on 2 battery modules: both 14.x volt
  
• I already took the main power feed off left it off overnight until I started working on the bike again.
  

@Korbin.. what do you mean by 'restarted your device'? Have I done that by taking the main power feed off overnight?
@Gerry: I didn't check the 80V on the complete battery pack. I assume having checked only 2 modules rules out the battery modules. As at a certain moment all was OK and a few minutes later the bike was completely dead. I don't think the batteries have been drained over this time and if 2 of them show OK voltage, all of them should be ok, right?

So back to the 12V: I would like to put an external 12V source on the white (Tamiya) connector, but I'm not sure what is positive and what negative. Both leads are completely white.. Who can help me out???

[Korbin Dallas]

Yes that is what I meant by restarting the device
Let

[empulsefan]

Haplo, the dc-dc converter has 2 white wires which should have 12v, also has 2 orange
wires which should meassure batteryvoltage. If not he can't produce 12 volts.

hopes this helps!

[Korbin Dallas]

Shunt or fusible link on the underside of each of the battery tops. If one blows that will kill the power to the dc/dc converter.  Just guessing

[Haplo]

Ah.. the mentioning of the 2 orange wires help.. That's probably what Gerry meant for checking the 80V.. I didn't get that.. But i'll check it next. I disassembled the rear already, assuming I probably would have to work there anyway..

What about my question about the white leads? Which is positive, which is negative? Is that a stupid question, since it seems simple, but no answer is coming? I thought I read somewhere it should be able to power the 12V circuit externally through that connector, right? So that was my plan assuming this would bypass the DC-DC converter so I can at least check if the rest of the bike is working like it should. Good plan or bad plan?

[Haplo]

Shunt or fusible link on the underside of each of the battery tops. If one blows that will kill the power to the dc/dc converter.  Just guessing

Hmm.. ok, good thought. I would be able to check this with the 80V check Gerry already mentioned right?

[Korbin Dallas]

Yes. the two orange wires on the same plug to the dc/dc are the high voltage and should read the voltage of the batteries, mine reads around 100volts and the bike is at 70ish % charge. put the meter either way if it shows a negative voltage then swap the leads. same with the 12v white wires. I was able to probe the back of the wires. Excellent idea about an external 12volt source might be fun to try. To me if you are not getting any voltage off the the 2 orange wires on the connector then remove the connector from the dc/dc converter and connect your meter to the pins on the connecter to eliminate the possibility that you dont have a good connection with the meter ( on the plug not the converter). If no voltage on the orange wires then i would check each battery to see if one of the 500a fuses has blown ( it is under the long orange cover on the top of each battery) I believe if one of those blows then the batteries are no longer in series.

[Korbin Dallas]

also on the dc/dc converter is says which is positive and which is negative. right next to the plug