When to know if a switched 12V is On or Off?

[dsevigny]

First, sorry about my bad english, I'm French!

Let me explain what happen with my 2014 S85 (RWD /w autopilot).

Last month, I installed a blackvue dashcam with the "ALWAYS ON" 12V available in the mic area. Everything works as expected and the dashcam is really always ON even when the car is Off.

Last week, a proffessional installer installed the NVX Sub/Amp. (At my request, the Amp was installed in the trunk instead of in the frunk like many people do)

Now my problem......

I just realized that the Amp is always ON (Blue light) even if the car is Off. Look bellow the picture of the blue light ON. I tried to put my keys at least 30' far from the car, etc.... The Amp is always ON !!!!!! The installer confirmed that he wired on a switched 12V.

Maybe I'm wrong but I remember that my cell phone stopped charging on the USB when I let this one in the car and start charging when I'm entering in the car so I assumed that th USB is a swicthed 12V. So now my cell plugged on the USB is always in a charge mode even when the car is Off. I made this test see when exactly the car accessories turn Off. Weird...

I'm really confused and try to understand and avoid the Amp to drain my 12V battery....maybe not enough but I want to avoid that if it's possible.

Thanks
Dominic

 

[Tech_Guy]

to confirm a switched 12v should be switched off when the car is off, an always on 12v is just that always on...

Also my cellphone stops charging as soon as I exit my car and shut the door the displays go dark and the usb port stops working. When the door is opened again the displays light up and the phone continues charging.

 

[msnow]

Pretty sure USB is always on.

 

[Tech_Guy]

my phone makes a noise when charging starts and I can hear this noise when I open my car door / turning the car displays and USB ports on again

 

[msnow]

my phone makes a noise when charging starts and I can hear this noise when I open my car door / turning the car displays and USB ports on again

I must be wrong then because you're saying it goes to sleep.

 

[Tech_Guy]

I'm quite sure, I've also seen a thread on here about jumping a relay in the fuse box to enable always on usb and 12v... think its in the dash cam thread...



Found it ...
Anyone with manual access - any constant 12V in the cabin?

FlatSix911 posted this which was quote of 2 other members

↑
Thanks. Unfortunately I don't really want something always connected to the OBD port (I like my installs to be all wired-in without any unnecessary wires showing). As for searching FlatSix911, I did, nothing popped up (here or on google, go ahead, search "12V power at the convenience plug", or even "12V convenience plug"

- all I found searching was OBD port and microphone grille). I know there is supposed to be a 12V source in the cabin somewhere, but I don't have access to the service manuals.

Here you go ...

↑

BTW, it's a simple matter to keep the 12v outlet in the console live all the time if desired. It's just a simple relay in fuse box #2 (the one on the passenger side under the removable cowling cover - see owner’s manual). Simply make up a jumper consisting of short piece of 14AWG or better wire with a couple of male 1/4" spade terminals.

Pull the front most passenger side relay out and insert the jumper into the now exposed 1/4" female receptacles, and you're done, the 12v outlet is now on all the time. You can quickly change it back anytime by removing the jumper and reinstalling the relay.

 

[dsevigny]

I make a test this evening! I plug my cell phone in the USB at 51%, closed everything and when I came back 30 min after, the cell was charged at 61% !!!!!!! Never happen before... I really need to understand what happen with my car! I'm pretty sure that the installer doesn't make the relay jumping in the fuse box just to plug the Amp.... I'm still confused....and stressed about that!

 

[Tech_Guy]

id check your fusebox #2 located in the passenger footwell to see if its been jumped as shown above...

 

[msnow]

Maybe this thread will be of help:
USB/Power Socket - Not Always On

 

[Tree95]

id check your fusebox #2 located in the passenger footwell to see if its been jumped as shown above...

The photos were originally posted by me Near annual replacement of 12V battery is typical according to Tesla Service Tech

In my March 2015 S85D, left hand drive, the fuseboxes are in the frunk under the the removable panel that runs across the rear of the funk near the windshield.

 

[philgrocks]

For those who did an always install of the blackvue camera... I did this with my model s. I measured how much power the blackvue uses and it is about 5W... So parked 8 hours it would consume just 40W... Pretty low.

But what I see is that if I do this I loose about 5 miles of range over 8 hours if blackvue is plugged in. Assuming 300Wh/m that is 1500W.

I assume this means that the 12V battery keeps getting charged up by the DC-DC converter. So significant power loss and does a lot more cycles of charging the 12V battery.

I looked at adding a power magic pro, but it won't turn off until 6 hours... Which means in typical use, It will only turn off for a short time.

I'm now thinking of wiring to a switched source.

Thoughts?

Thanks

Phil

 

[cookie99]

For those who did an always install of the blackvue camera... I did this with my model s. I measured how much power the blackvue uses and it is about 5W... So parked 8 hours it would consume just 40W... Pretty low.

But what I see is that if I do this I loose about 5 miles of range over 8 hours if blackvue is plugged in. Assuming 300Wh/m that is 1500W.

I assume this means that the 12V battery keeps getting charged up by the DC-DC converter. So significant power loss and does a lot more cycles of charging the 12V battery.

I looked at adding a power magic pro, but it won't turn off until 6 hours... Which means in typical use, It will only turn off for a short time.

I'm now thinking of wiring to a switched source.

Thoughts?

Thanks

Phil

what? is this true?? You lose 5 miles of range every 8 hours??? 15 miles per day for a dashcam that seems way too much range to lose.. especially if you're out on vacation..

 

[philgrocks]

what? is this true?? You lose 5 miles of range every 8 hours??? 15 miles per day for a dashcam that seems way too much range to lose.. especially if you're out on vacation..

The dash cam is only 5watts (measured), but I believe the DC-DC has to keep topping off the 12V battery and that is why so much energy is consumed as the DC-DC is probably not efficient for just 12V charging.

 

[whitex]

what? is this true?? You lose 5 miles of range every 8 hours??? 15 miles per day for a dashcam that seems way too much range to lose.. especially if you're out on vacation..

Have been running dashcams in our Model S'es and it's not that bad. It does seem to drop more at first (first few hours), but I park at the airport a week a time and average is 2-5 miles per day, depending on outside temperature - 2ch BV running 24/7. I don't wake the car every day, nor run any polling services that query the cars.