DIYMobileAudio.com Car Stereo Forum banner
1 - 8 of 8 Posts

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #1 ·
Well, it's time that I get this install done the way I want it and completed so I can finally get a tune on it. Here's the equipment that I'll be using for my current iteration:

AudioFrog GB25 Dash Midrange
AudioFrog GB10OE Tweeters
AD W800 Neo Midbass
AudioFrog GS25 Rear Fill
SI SQL-12 in Sealed .8cf box
Helix V-Eight MK2 DSP/Amp w/Conductor
Rockford-Fosgate TX750X1bd Amp (for sub)
Sound Treatments - Resonix CLD/FiberMat, Dynamat Extreme, and Roadstage audio dampener

My last iteration was all that same equipment, except a D'Amore E1000.1 amplifier. The reason I'm using the RF amp this time is because I want to hide all of the equipment in the right rear wheel well.

In a Tesla SR+, we don't have a factory sub or sub amp, so the right rear wheel well is completely open. The car also didn't have the factory tweeters activated, and no rear deck speakers at all.

Let's dive right in with the amp rack and power supply configuration. This is my prototyping cardboard to see what fits:
Motor vehicle Hood Automotive design Vehicle Sky


The first pass I was seeing if I could fit a P Six Ultimate in the future, and also noticed there was a bunch of room below the RF amp. So I decided to move the RF amp down farther and use the middle to install the fuse/distribution block, and the isolator relay.


Rectangle Textile Sleeve Font Grass

This is most likely the final configuration of the rack with everything mounted up. Most people will be wondering what the heck is with the Stinger relay, the load resistor, and the little control box.

A quick primer on dealing with the 12V system in the Model 3. Under the rear seat there is a power post that provides the car with the 12V system (13.8V) using a DC-DC converter that's good for around 175-200A total draw. When the car goes to sleep, the converter shuts down, so there isn't any 12V power anywhere. So that means the input filtering caps in the amplifiers basically drain. When you get in the car, it wakes up, and the converter powers up. The amps of course quickly charge their capacitors, and the tesla monitoring system notices this rapid current draw and panics. It then throws a bunch of errors on the screen and shuts the system down rendering the car un-drive-able. Not great. So what most folks do, it put a 1-5ohm 100W resistor across the terminals of the relay. This means that when the converter powers up, the amps slowly charge their caps across that resistor before the relay kicks on and powers up the system. Once the system is up, electricity takes the easiest path and usually ignores the resistor.

Personally, that resistor bugs me a little because it's always on, meaning there's a parasitic heater/draw. Also, if your relay is undersize (like people using 80A - Don't do that!), the system will try to draw more current across the resistor too, making it heat up and/or flame out! So what I did, is designed a simple controller using an Arduino and a dual-relay board. What happens here is that when the 12V REM wire powers up, it turns on the Arduino. The Arduino turns on Relay 1 on the board, which instantly puts the 1Ohm resistor across the power terminals of the stinger to allow the amps to pre-charge slowly. By slowly, I mean we wait about 500ms, and then Relay 2 turns on. This relay basically turns on the Stinger relay, bringing up the whole power system. About 300ms after that, Relay 1 turns off which takes the resistor out of the circuit with the Stinger. This ensures that the resistor doesn't really have much of a chance to stay on and overheat/etc. If the system draws too much power, then fuses should blow. There's also a fuse on the resistor too just in case. Ok, that was a lot.. And yes, some folks power their Tesla systems off a 2nd battery in the trunk if they have a big system, OR use the front battery. I'm currently using the front battery, but again, the Tesla watches the charging and draw on that front battery too.. so we really should avoid it. Plus, that means we can have a nice short like 5-6 foot run of wire from the converter to the amp rack.

So tonight I pretty much mounted all the components for the amps, and did a test fit:
Automotive design Motor vehicle Eyewear Bag Sunglasses


Nice, it all fits! Tommorrow I'll tackle some wiring, and make a better 3D printed case for the microcontroller. Eventually I also plan to 3D print an access door to go in the carpeted panel that covers the rack. That way I can quickly replace fuses or service the DSP/Microcontroller as needed. I'm also thinking of having a button that kills off the REM wire so the whole system can be powered down for service.
 

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #5 ·
Did some more wiring on the rack tonight. Most nights I only get an hour or two after my son is down for bed, so things going slow. Mainly got all the power, ground and remote wiring done. Still need to finish up the relay control module.
Next up will be signal wiring. I’ve actually decided to use Deutsch DT connectors for the inputs and outputs to save rack room and make it easier to do. Those should come in tommorrow.

Circuit component Corded phone Font Gas Electrical wiring

was hoping to get the wiring cleaner, but the space is pretty tight. Still amazed that little RF T750 only needs 8ga wiring for 750W.
 

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #6 ·
Today's Progress:

Got my delivery of the Deutsch (DT) connectors and crimping tool. These things are slick!
Cameras & optics Finger Door Gadget Electronic engineering


Found a 3D printable mount (Wide DTM clip by ncampos976) and attached them to the amp rack. Made cables with ferrules on the other end and wired up the Helix V Eight output sections.
Aircraft Wing Missile Aviation Toy airplane


Did some wire management/cleanup, and got most of the relay controller module wired. Now I just need to finish the enclosure and mount it. Then I can get this thing in the car! The inputs for the Helix, I'll just be using the factory connectors since they disconnect easily. Here's a shot of the rack as it is now. It's getting a bit crowded shoving all that stuff in there, so it's hard to make the wiring super clean. Could probably figured out how to mount the resistor/relay combo somewhere on the car's body I suppose, but I like everything all in one place for easy access.

Circuit component Office supplies Font Gadget Office equipment
 

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #7 ·
Finally got the amp rack completed to put back in the car. Here's a shot of the final config:

Electronic device Cable Circuit component Wire Electrical wiring


I wish I could have made it cleaner looking but it's pretty packed for the size!

And here's a quick video explaining the components and showing how my custom power controller works:
 

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #12 ·
A few more 30m sessions of work, and I'm almost done! Just need to attach the conductor wire for the Helix, and find an accessory wire place to tap and run for the amp board. Here's things all connected up and ziptied. I'm also planning on getting some liquid electrical tape just as a precaution for any of the terminals. You can see I tapped the penthouse and have an in-line 150A fuse. Then back near the amp board there is a circuit breaker (200A) just to mainly act as a disconnect should I need to service things and not want to pull up the seat and mess with things under there.

Hood Motor vehicle Automotive lighting Automotive fuel system Automotive design

Motor vehicle Automotive design Vehicle Audio equipment Electrical wiring

Hood Automotive lighting Motor vehicle Automotive design Trunk

Hood Motor vehicle Automotive design Steering part Steering wheel


Whew, that's a lot of stuff crammed into that space, but man, it's nice to have it all there and still have space in the trunk for stuff. Ultimately, you can quick-disconnect the sub too and then you could remove it to have 100% factory space in the trunk. I'm tempted at some point to add DT connectors for the input part of the helix, just so that I could build a bypass harness should you easily want to return to stock for testing or something.. but then again, with the T-harness I built under the front dash it's easy enough to go back to stock there.
 

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #14 ·
I'm disappointed you are near the end already. This journey was too short.

So just so I understand - Instead of connecting to the front battery, you connected straight to a post somewhere between the DC-DC converter and the 12V battery? What was the reason for that as it seems to have complicated the build a little bit. Fear that the battery wouldn't keep up because it only charges at XXA but you know the converter can handle XXA^2(175A-200A)?

I'll be installing into a hybrid soon and the 12v is basically charged the same way. I have no idea the capacity of the charger(Well I'm assuming around 100A but hoping more) and was planning on getting specs once I rip the car apart. But I keep going back and forth on how big of an amp to put in, which pulling the car apart may be the only solution to finally putting my thoughts to rest.

Do you have a link or schematic to your Arduino/Relay build?

TIA!
Oh the journey will continue. I'll detail my speaker installs and things next. I already have them installed, but have a lot of pictures and things from when I did them. Regarding the power connection; for the last year or so I've been running just fine off the front battery. I just really wanted to rebuild my amp rack and move things as the previous install had the amps hanging from the rear deck. There's a lot of discussion that you don't want to mess with the front battery because the car is monitoring it closely, and the excessive draw there could cause it to die not being very large at all. So yeah, the converter seemed like the better choice, and a nice short 5' run of Knuconceptz 4ga, which is more like a 3ga its so big. Given that short run and the wire, it seemed safey to run the system that way vs. the longer run of 4ga. I really didn't want to buy larger wire and fish it around.

Regarding a hybrid, most things I see say to keep your power limited and run off the battery.

And finally, regarding my arduino/relay thing.. doesn't seem to work. The theory seems sound, but the Tesla does NOT like having that resistor put in and out of the circuit like that one bit, it trips one of the car's efuses. So back to the way everyone else does it; putting the 1 ohm resistor across the power terminals of the 200A relay. I'll have to think of some other clever method, but for now, this should be ok.
 
  • Like
Reactions: bbfoto

· Premium Member
2021 Tesla Model 3 SR+
Joined
·
159 Posts
Discussion Starter · #16 ·
Alright, good progress the last day here. Ran some 18ga KnuKonceptz wire under the rear carpet and back to the amp board. Then I tapped into the USB-C power supply here in the back of the center console. So when the USB ports are live, the amps turn on and the Stinger relay does too. You can also see my light pipes and a little LED controller box for some ambient lighting. Stuck a 5A fuse in there for good measure too.

Light Blue Hood Automotive lighting Trunk


And here's a shot of the final config of the amp rack with everything attached.

Vehicle Motor vehicle Hood Car Automotive design


I used red liquid electrical tape and painted all the terminals on the relay and the circuit breaker in the upper left. That breaker comes in handy for servicing things. There still a 150A fuse near the DC-DC converter under the seat for added protection.

I set the gains on the fosgate amp, and tested to make sure everything works. Sure enough, it sounds just like it did before moving everything to this space. That little RF amp puts out plenty of power, and the SQL-12 seems to be just as loud as when it was on the E1000.1. I have the gains 1/2 way up, so there is that. Kinda wish I could go a bit lower, but the SQL is such a power hungry monster.

Here's a shot of putting back the carpet trim
Motor vehicle Automotive design Sleeve Automotive tire Gesture


The top of the carpet has some slots in it for airflow, and under the amp board is a good 3" of open space, and behind it is the air vents to the outside bumper area. So there should be OK airflow in this area. The metal all has the 3-in-1 CLD on it, so that should help to keep temps down a little from outside solar gain.

Finally, a boring stock looking trunk:
Hood Automotive lighting Membranophone Grille Automotive tire


Lift up the trunk cover though, and the SQL-12 lives in there in a sealed .8cf box. It's almost too tall of a sub to leave enough room for excursion, but it fits!

Vehicle Hood Automotive tire Automotive design Car


Now the question is... keep the SQL or go with a GB12, and make a much cooler looking sub area. I dunno, I'm pretty worn out and this all sounds pretty great.

At this point I just need to finish the driver's side door soundproofing, and I can get this thing in for a tune and just enjoy it. Very happy with how it's all turning out, and learning a lot along the way.
 

Attachments

1 - 8 of 8 Posts
Top