I need help finding the culprit

[MagicianElectrician]

Maybe I'll pull the driveshaft out to disconnect the front end from the motor and see if it's the same or not. Eliminate that possibility at least

 

[MagicianElectrician]

Are you sure you have a temp sensor on the battery? That temp seems WAY to high.

Can you screenshot the data?

Oh no thats motor

 

[MagicianElectrician]

Ok I took it for a spin. Same thing. 4-5 passes and then half speed. This is when it went into "limp" mode. Probly half the speed as normal. About 3 min later: shutdown. Nothing. Battery was fresh charged to 12.6v before I got there.

 

[MagicianElectrician]

And another thing: when I got home and took the battery out to charge it, I heard a real faint sizzle kind of sound from somewhere. So I held the battery by my ear just to see and sure as s*** it was the battery cuz it did it again by my ear. Wth could that be?? I've never heard a lipo pack do that before

 

[MagicianElectrician]

It's still taking a charge just fine. And the voltage between all balance leads is correct. Also, I checked continuity at the ESC leads both to positive and negative- all good.

 

[WickedFog]

It's still taking a charge just fine. And the voltage between all balance leads is correct. Also, I checked continuity at the ESC leads both to positive and negative- all good.

It's probably that battery is getting severe voltage sag. Does that Traxxas telemetry stuff have a log file?

 

[xjtorc]

what is this? "MAX 213.6"

 

[MagicianElectrician]

I have no clue

 

[xjtorc]

View attachment 259327
what is this? "MAX 213.6"

This was bothering me, so I did some investigating. First off, the Traxxas documentation on their link app is nonexistent. Plenty of links to download it and, if you dig really hard, you stumble upon a blog discussing its features, but zero details on how to actually use it. No descriptors of what each dashboard widget does. So, I downloaded the app on my phone, set up a dashboard, and added the voltage widget so I could figure it out myself.

When setting it up a dashboard from scratch and adding the Voltage widget, you add the secondary "max" field as an option. It has a cap you can set that maxes out at 50 Volts. 213.6 is weird and obviously doesn't make any sense. If it's consistently reading a max of 213.6 in that field, I would imagine there's something wrong with either your external telemetry system or perhaps the ESC itself.

Do you have additional externally added telemetry components or are you just getting the readings from the stock Traxxas electronics?

 

[MagicianElectrician]

I have added my LED headlights, tail lights, and "body" lights. The body lights use 1 onboard controller. Each set is plugged into the receiver with a JST plug for power.

 

[MagicianElectrician]

I have added my LED headlights, tail lights, and "body" lights. The body lights use 1 onboard controller. Each set is plugged into the receiver with a JST plug for power.

But just FYI, I had all of that connected before when I was hitting 74mph. Actually today when I ran it I got it up to 57mph again. Maybe the cold weather was affecting the battery, but I'm still not where I was at with 74. We're still talking about 15mph slower. If it was maybe 5 slower I'd accept that, but 15 is too much. That's says there's a problem

 

[MagicianElectrician]

So I'm still without a definite answer to this. I decided to check continuity between leads on the ESC again today as well as the motor leads and everything checked out just fine. I've yet to disconnect the motor from the drivetrain to test the rolling chassis for any unusual resistance or to read voltage between motor leads while manually spinning it with a drill. I guess there could still be something messed up in 1 (or both) differentials and/or wheel bearings. I'm gonna try and do that tomorrow. I want an answer to this!

 

[Beer_Goggles_RC]

So I'm still without a definite answer to this. I decided to check continuity between leads on the ESC again today as well as the motor leads and everything checked out just fine. I've yet to disconnect the motor from the drivetrain to test the rolling chassis for any unusual resistance or to read voltage between motor leads while manually spinning it with a drill. I guess there could still be something messed up in 1 (or both) differentials and/or wheel bearings. I'm gonna try and do that tomorrow. I want an answer to this!

Good idea, even one bound up drivetrain bearing could be the culprit.

May have been asked before, but are the motor and esc warm after these slower passes?

 

[Mrgoodwrench35]

If I heard a 'sizzle' sound coming from a lipo, that lipo goes outside in a bucket. Done.

 

[MagicianElectrician]

Good idea, even one bound up drivetrain bearing could be the culprit.

May have been asked before, but are the motor and esc warm after these slower passes?

I am not familiar with this word you speak of: slower.

 

[MagicianElectrician]

If I heard a 'sizzle' sound coming from a lipo, that lipo goes outside in a bucket. Done.

Well, it still charges and still gets up to 12.6volts. And the charger hasn't shown any messages about something wrong. So idk. Drive it til the wheels fall off

 

[Mrgoodwrench35]

Theyre not supposed to be audible. Be sure you store them in lipo safe bags.

 

[Beer_Goggles_RC]

I am not familiar with this word you speak of: slower.

But just FYI, I had all of that connected before when I was hitting 74mph. Actually today when I ran it I got it up to 57mph again. Maybe the cold weather was affecting the battery, but I'm still not where I was at with 74. We're still talking about 15mph slower. If it was maybe 5 slower I'd accept that, but 15 is too much. That's says there's a problem

 

[MagicianElectrician]

I disconnected the motor today and tested voltage between leads while spinning it manually. All 3 read the same. Then I went to my local hobby shop to ask them what they think it is. His first question was have I ever changed the wheel bearings. I have not. Then he was certain the problem is that: worn bearings. Thoughts anyone?

 

[xjtorc]

I disconnected the motor today and tested voltage between leads while spinning it manually. All 3 read the same. Then I went to my local hobby shop to ask them what they think it is. His first question was have I ever changed the wheel bearings. I have not. Then he was certain the problem is that: worn bearings. Thoughts anyone?

I think that sounds like a typical hobby shop response lol.

You changed the battery and added cooling fans. You made changes to the electrical system and immediately saw poor results. I don't think the wheel bearings yeeted themselves between a battery swap and fan install.

Tear the rig down and check the bearings?