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Towing with the new 16v battery

VandalSibs

I am One with the Force, and the Force is with me
Oct 28, 2019
256
328
Spokane, WA
Has anyone gotten an answer on if brake controllers will work with the new Model Y's that have the 16v li-ion batteries? The manual says that the connection is there (when the tow package is installed), but the talk is that the power for the brake controller doesn't work. And I can't seem to get a straight answer from my local Service Center...

I'm looking to tow a RV in the future, and if it's over 1600 lbs, the manual says a brake controller is necessary...
 

ATPMSD

Active Member
Mar 12, 2021
2,028
1,977
Atlanta, GA
The owners manual for the Y says that a brake controller is needed for anything over 1685 lbs, so it's something I want to make sure will work...
I understand but pretty sure it does not have to be a “brake controller,” just a braking system. Might want to check as the surge brake is very simple.

As to whether a controller will work, these are sold by various manufacturers and you will have to ask the company about each system you are interested in. For example:

 
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>> The manual says that the connection is there but the communication with the brake controller doesn't work.

@VandalSibs As a possible fix, the Curt Bluetooth brake controller could be an easy to use solution.

Has anyone tried one of these Curt Echo BT Brake controllers with the 4S voltage output?
Is this controller fully compatible with the Increased voltage?
 

VandalSibs

I am One with the Force, and the Force is with me
Oct 28, 2019
256
328
Spokane, WA
Has anyone tried one of these Curt Echo BT Brake controllers with the 4S voltage output?
Is this controller fully compatible with the Increased voltage?
Interestingly, I just ran up to my RV dealer (wife and I are picking up our trailer on the 28th) and I had them hook up the 7-wire tester. The brake controller line works, it's the "Charging" run that doesn't... so standard brake controllers will work just fine.
 
Interestingly, I just ran up to my RV dealer (wife and I are picking up our trailer on the 28th) and I had them hook up the 7-wire tester. The brake controller line works, it's the "Charging" run that doesn't... so standard brake controllers will work just fine.
So the voltage output, " Aux 12V+ Charging" pin is Not active?

If true, then this Curt Echo device I don't believe will operate, as it requires this #4pin to pass current to the "Trailer Brakes" #2pin.

Possible anyone can test to verify?
IMG_7686.png


Some of the choices they make are confusing from a users perspective...
What if people need that pin at a 12V nominal voltage to operate any of the standardized devices that use it...
 

ATPMSD

Active Member
Mar 12, 2021
2,028
1,977
Atlanta, GA
Interestingly, I just ran up to my RV dealer (wife and I are picking up our trailer on the 28th) and I had them hook up the 7-wire tester. The brake controller line works, it's the "Charging" run that doesn't... so standard brake controllers will work just fine.
I wonder if this is by design? I would submit a service request to have it fixed and see what happens.

Also I found that this if often switched power, so the car has to be awake.
 
Don’t submit a service ticket. It was designed this way.

I spent a fair amount of time looking into this before getting my tow package instalked, and I even went through the wiring diagrams to make sure all 7 pins were active. I then opened the owner’s manual and the answer was right in front of me. This is a frustration for me because I use a Tekonsha Prodigy RF brake controller that won’t get power unless I splice something in.

C5CCCA02-9A86-430D-9533-383E1A156C5A.jpeg 48C8F296-6942-4A50-AD8B-46610891CB57.jpeg
 
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VandalSibs

I am One with the Force, and the Force is with me
Oct 28, 2019
256
328
Spokane, WA
Don’t submit a service ticket. It was designed this way.

I spent a fair amount of time looking into this before getting my tow package instalked, and I even went through the wiring diagrams to make sure all 7 pins were active. I then opened the owner’s manual and the answer was right in front of me. This is a frustration for me because I use a Tekonsha Prodigy RF brake controller that won’t get power unless I splice something in.

View attachment 898745 View attachment 898746
I would argue that "designed" that way isn't quite right, maybe "designed that way for now"? Haha...

What's interesting is that language in the owner's manual about the different low-voltage batteries wasn't there when I got my Y back in May.
 
I'd love to see the auxiliary power circuit activated, but I don't think that's likely without a hardware swap of some flavor. The wiring diagrams have auxiliary power going into the trailer inline connector from the left body controller, but none coming out where the trailer connector plugs into the inline. I'm thinking that circuit terminates somewhere between the two.

I'm not sure what I'll do about it, if anything. My boat trailer has surge brakes, and It's pretty rare for me to go over 2,000 lbs with my utility trailer. I keep an old Expedition in the garage to pull with, so I don't really need to solve this. If I did, I would probably use the factory wiring for a hardwired controller in the cabin.
 

VandalSibs

I am One with the Force, and the Force is with me
Oct 28, 2019
256
328
Spokane, WA
I'll be using the factory wiring for my brake controller, as the trailer is pushing 2,700lbs dry.

Regarding the accessory power connection, I wonder if they just haven't figured out some sort of step-down/voltage reduction for that just yet (which would be weird, as all the other 12v stuff in the car is working just fine).
 
Yet another consequence of Tesla's brilliant idea to put a 16V battery in a car where everything for cars is designed for 12V. Someone needs to help the Tesla engineers to understand the real world.
Other than working with Li Ion, I'm not sure I understand any advantage gained from a 16Vdc system VS a 12Vdc system.

Wouldn't a LFP LV system have retained full DC compatibility, and offered nearly the same advantages of the Li Ion 4S system?
 
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Furthermore the car actually steps down the voltage to 12V for powering car’s electronics (ECUs) which leads to extra complexity and decreased reliability.
Is there anywhere that details this technically well?
Would like to learn more about how they have gone about it and any Pros/Cons as a result.

I assume with a Li Ion based system, there is more "usable" capacity over the voltage range for 12Vdc based components?
But there are certain losses from stepping down as well?
Strange if thats how they have done it, they apparently didn't allocate enough 12V current to drive the trailer power rail.
 
The lithium LV battery has much less capacity than the older lead acid 12V battery. Without PCS power it drains twice as fast (<10 minutes in my experience) as the car pulls ~20A when powered on.

When airbags and pyrofuse blow, the vcfront will cut off power the half of the car in order to give occupants more time to exit the car and grab their belongings before the LV battery drains to zero.
 
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