Almost had a Tesla wiring fire - what did I hook up wrong?

[SFL_Electric]

So i am working on installing an aftermarket sub and amp like many others here.

Pre-install research:
I have had my tesla 3 years and did my research before embarking on this project. I read many threads on this forum, Reddit and DIYmobileaudio.com before attempting anything. I have installed several audio systems on my prior ICE vehicles, this is my first EV audio install.

What am I installing:
I have the generally the same equipment as the post referenced in the guide below: the same LC2i pro, same Stinger SGP32 relay and same resistor (RX24 200W 2ohm Amazon.com ). Not sure where I went wrong but after having it hooked up and not turning on, getting multiple error messages and almost starting a fire, something wasn't right.

How did I hook it up:
I followed the wiring guide posted in this thread: Installed an amp and subs over the weekend . I am using 4 gauge wire for the primary amp power and I used 14 gauge wire with an inline fuse to hookup the resistor across the two main poles of the relay (I put a 30 amp fuse in the inline ruse holder, i should probably put a smaller one like 5 amps, will do on next attempt).

The only deviation I took from his wiring guide was that I tapped my remote turn on to the 12v red wire in the bundle at the passenger footwell for VC_Right instead of the 12v in the center console. This line has more power so i did not need a second relay to hookup before the Stinger relay, not a big difference, otherwise wired the same. I tapped VC_Right as shown here:

How'd it go?
So what had happened was... once I hooked it all up, and tested with a driver in the seat... the amp and LC2i were not turning on which was strange because my multimeter was showing 12v at each of the device power terminals.

I got several error messages on the Tesla screen:
VCFRONT_a552 - Condition detected with a vehicle controller
VCFRONT_a192 - Electrical system is unable to support all features
BMS_a063 - Unable to charge
VCFRONT_a180 - Electrical system power reduced

So I went inside my house from the garage to grab my laptop which took about 2 minutes and got back to the garage and smelled something heating up. I had all the components sitting on a piece of board just like @thesuffering did in his photo in the wiring guide I followed. I quickly did a touch test to see what was getting hot before i burned my house down and felt it was the resistor so i clipped the wires to it real fast to defeat the circuit. I picked it up by one of the connected wires because it was way to hot to touch and the board was dark brown below the resistor in the same shape of it! It almost burned the wooden board, had it got any hotter it would have. Thank God it didn't because how was I going to explain that to the wife?!?

I was able to clear the errors by performing the full power reset (power down system, disconnect 12v battery and disconnect the connector right next to the penthouse connection for a moment, then reconnected and restarted the car and all messages were clear. I disconnected the primary amp connection at the penthouse for the moment until I can get some direction from those of you out there smarter than me.

So..... what did I do wrong? Did i get the wrong resistor or just a bad one?

 

[Jerry Ham]

The circuit that you used as a guide used a 100w 5 Ohm resistor. You used a 2 Ohm resistor. So you were pulling a lot more current.

 

[thesuffering]

Agree with what @Jerry Ham says. There is quite a big difference in resistance. Think about an 4ohm amp and bridging it to 2ohms, you get more power right? Same idea here, except in reverse. The higher the resistance, the lower the power.

Those errors you got sound like the in-rush current we are trying to prevent. We only want to trickle charge the caps, not send a huge rush of current at once.

As far as the resistor getting hot and burning, it could have been seeing well over 200w is what im guessing and without you having an appropriate size fuse prior down the line its going to burn. Id also triple check all your wiring and that wire you are using for remote, that very well could have something to do with it. You want the remote wire to work with the seat sensor in the drivers seat so it will go to 0v when you are out of the car and close the door.

PLEASE, whatever you do, use more fuses than you think you need and only use as large of a fuse as is needed. a 30 amp fuse will not prevent a fire on a wire that cannot handle the current, the fuse is meant to pop before the wire gets too hot and burns down your car.

 

[SFL_Electric]

Thanks for the responses and thank you to @thesuffering for his awesome write up that I followed and his reply to the thread. So I was able to get it all figured out.... let me explain what happened to help others not make the same mistake. It drives me nuts when people post threads asking for help and then never follow up when they figure it out or follow up and just say, thanks i fixed it. That doesn't help the next person coming along with the same problem.

I hate to admit to such a careless and rookie mistake but I've got to be honest with myself and hopefully it will help someone else down the line. So after racking my brain, researching resistors online and making sure several times that my wires were all good, I asked a local buddy of mine to come over and double check my work with a fresh pair of eyes to make sure I didn't miss something or over look something.

I'm guilty of researching this so much that I paid so much attention to the parts I didn't know (the relay and resistor stuff) which were actually hooked up just fine. The relay and resister were functioning correctly, nothing was damaged , so I overlooked double checking the easiest wires to connect! They were literally the ONLY connection that I didn't double and triple check because in my mind it was too easy to screw up because I've hooked them up a bunch of times.

Well.... I did. I SCREWED UP. That's why you don't work on this stuff at midnight. I hooked up the power to the amp backward! I switched the power and ground and back fed ground into the positive circuit therefor overheating the resistor. In a normal circuit that would have just blew a fuse or a component but I guess the resistor was buffering the circuit crossover causing it to get insane hot.

Well that's it, please don't make my mistake. When hooking up equipment late at night, don't get sloppy and double check ALL connections, (not just the ones you think you might have gotten wrong).

 

[SFL_Electric]

Agree with what @Jerry Ham says. There is quite a big difference in resistance. Think about an 4ohm amp and bridging it to 2ohms, you get more power right? Same idea here, except in reverse. The higher the resistance, the lower the power.

Those errors you got sound like the in-rush current we are trying to prevent. We only want to trickle charge the caps, not send a huge rush of current at once.

As far as the resistor getting hot and burning, it could have been seeing well over 200w is what im guessing and without you having an appropriate size fuse prior down the line its going to burn. Id also triple check all your wiring and that wire you are using for remote, that very well could have something to do with it. You want the remote wire to work with the seat sensor in the drivers seat so it will go to 0v when you are out of the car and close the door.

PLEASE, whatever you do, use more fuses than you think you need and only use as large of a fuse as is needed. a 30 amp fuse will not prevent a fire on a wire that cannot handle the current, the fuse is meant to pop before the wire gets too hot and burns down your car.

Thank you for the reply. As mentioned above I fixed the main issue but I am tapping the remote lead from a different spot than you did which poses a less than ideal situation so I might change that.

The spot I tapped was super easy to get to but the problem is that it shuts off the very second my butt is out of the seat. Even leaving the door open, that wire on VC_Right is tied directly in with the seat sensor and shuts voltage as soon as the driver gets up or even leans over with you butt half in the seat, which is not what I want because it causes the sub to shut off.

So if you don't mind, can you confirm if the brown colored wire you tapped in the center console, still stays powered until you get out of the seat and close the driver door? If so, that would be a much better trigger for the remote line in my opinion as I don't want it shutting off each time I get up or lean over and don't put enough pressure on the seat (that seat sensor is quite sensitive). I'm asking because I have my radar detector plugged in the 12v outlet in the center console and that stays powered full time and never shuts off. Is that a different connection than the brown wire?

 

[thesuffering]

Brown wire i can confirm will give you the desired behavior. If you open the door and then close it again and there is nobody in the seat it cuts power because nobody is in the car and it should shut off. If you are still in the seat you can open and close the door and it all remains on.

Brown wire is a different wire than the cigarette lighter. Cigarette lighter remains on for some time after you exit the car. The brown wire works directly with the seat sensor.

 

[Panams16]

Thanks for the responses and thank you to @thesuffering for his awesome write up that I followed and his reply to the thread. So I was able to get it all figured out.... let me explain what happened to help others not make the same mistake. It drives me nuts when people post threads asking for help and then never follow up when they figure it out or follow up and just say, thanks i fixed it. That doesn't help the next person coming along with the same problem.

I hate to admit to such a careless and rookie mistake but I've got to be honest with myself and hopefully it will help someone else down the line. So after racking my brain, researching resistors online and making sure several times that my wires were all good, I asked a local buddy of mine to come over and double check my work with a fresh pair of eyes to make sure I didn't miss something or over look something.

I'm guilty of researching this so much that I paid so much attention to the parts I didn't know (the relay and resistor stuff) which were actually hooked up just fine. The relay and resister were functioning correctly, nothing was damaged , so I overlooked double checking the easiest wires to connect! They were literally the ONLY connection that I didn't double and triple check because in my mind it was too easy to screw up because I've hooked them up a bunch of times.

Well.... I did. I SCREWED UP. That's why you don't work on this stuff at midnight. I hooked up the power to the amp backward! I switched the power and ground and back fed ground into the positive circuit therefor overheating the resistor. In a normal circuit that would have just blew a fuse or a component but I guess the resistor was buffering the circuit crossover causing it to get insane hot.

Well that's it, please don't make my mistake. When hooking up equipment late at night, don't get sloppy and double check ALL connections, (not just the ones you think you might have gotten wrong).

I have the same issue and happened today with a resistor I used, was getting hot and when I increased the volume it started sending weird static signal to the subwoofer, after a few second burnt smell was coming and it was From the resistor. Had to yank the wires off the resistor to stop it.

My power and ground looks good so no idea what’s going on on my system. I have the 100w 5ohm resistors but these get hot without even having the volume high.