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nhirsch
Member
Just found this thread. I did my always-on dashcam install last month and then improved it (so i thought) with an always-on "Tesla's" box in the center console. Here are the links:
Dropbox - Dashcam install in Model 3.pdf
then:
Dropbox - Always on Power in Model 3 console.pdf
but then I got a service message saying I needed to take car in for service. Service said the dashcam was at fault. The model 3 has a battery monitoring system and even small (blackvue is 350mw with wifi) power leakages cause it to trip. This is unsatisfactory IMO given the battery under the car should be, like my model S has been doing for 4 years) replentishing the 12V battery with enough power to run the blackvue. I've heard of at least two others who have this same problem now. Don't tell me Tesla won't allow in the Model 3 an always on dashcam that gives the owner some form of security/safety while parked as well as while driving. Here are the words on the service center report:
Concern: Customer states car needs service/contact Tesla service alert is on.
Corrections: 12V Battery and Fuses General Diagnosis
Inspected 12 volt battery assembly, found aftermarket camera's installed and connected
directly to the battery. Due to the consumption monitoring capabilities of the model 3 this
installation directly at the battery will lead to alerts and or loss of 12v. Replaced 12 volt
battery as one time good will. Disconnected aftermarket power wires from 12v battery.
Concern: Remote diagnostics show that this vehicle's 12V battery is in need of an urgent
replacement due to frequent overcharging.
Corrections: Battery - Auxiliary - 12V
I've asked service to please have the error message as being able to be dismissed and/or fix the problem and let the big battery keep the smaller 12V battery sufficiently charged to allow at least a dashcam to function always-on. I hope you will agree and be vocal in that regard.
Dropbox - Dashcam install in Model 3.pdf
then:
Dropbox - Always on Power in Model 3 console.pdf
but then I got a service message saying I needed to take car in for service. Service said the dashcam was at fault. The model 3 has a battery monitoring system and even small (blackvue is 350mw with wifi) power leakages cause it to trip. This is unsatisfactory IMO given the battery under the car should be, like my model S has been doing for 4 years) replentishing the 12V battery with enough power to run the blackvue. I've heard of at least two others who have this same problem now. Don't tell me Tesla won't allow in the Model 3 an always on dashcam that gives the owner some form of security/safety while parked as well as while driving. Here are the words on the service center report:
Concern: Customer states car needs service/contact Tesla service alert is on.
Corrections: 12V Battery and Fuses General Diagnosis
Inspected 12 volt battery assembly, found aftermarket camera's installed and connected
directly to the battery. Due to the consumption monitoring capabilities of the model 3 this
installation directly at the battery will lead to alerts and or loss of 12v. Replaced 12 volt
battery as one time good will. Disconnected aftermarket power wires from 12v battery.
Concern: Remote diagnostics show that this vehicle's 12V battery is in need of an urgent
replacement due to frequent overcharging.
Corrections: Battery - Auxiliary - 12V
I've asked service to please have the error message as being able to be dismissed and/or fix the problem and let the big battery keep the smaller 12V battery sufficiently charged to allow at least a dashcam to function always-on. I hope you will agree and be vocal in that regard.
Please keep us posted! At least they didn't charge you for a replacement battery...hope that doesn't happen to me next week.
Jason Bourne
Member
Not sure if I'm excited about the specs of that battery backup. It says it'll provide up to 12 hours of battery run time for the camera. That's basically overnight, then it needs approx 1 hour to fully recharge (much shorter than my commute to work). I'm not sure there's any better option, but I may just wait until Tesla makes a reasonable option available.
swaltner
Active Member
I don’t have a Tesla, so can’t test this hypothesis out, but I wonder if the reason that hard-wired dashcams trigger battery alarms is that hey are bypassing some current sensing in the Model 3 that is used to monitor the health of the 12v battery.
My thought is that the onboard computer is monitoring the power in/out of the 12v battery, eventually noticing a discrepancy (because some power is directed to the BlackVue and bypassing it’s monitoring) and then flagging the 12v battery as failed, even though it’s really fine.
If that’s really what's happening, you would want to find and tap into an always-on circuit. In addition, that would also mean the add-on BlackVue battery wouldn’t help because you would still be charging it from the main battery due to the issues raised by @Jason Bourne.
My thought is that the onboard computer is monitoring the power in/out of the 12v battery, eventually noticing a discrepancy (because some power is directed to the BlackVue and bypassing it’s monitoring) and then flagging the 12v battery as failed, even though it’s really fine.
If that’s really what's happening, you would want to find and tap into an always-on circuit. In addition, that would also mean the add-on BlackVue battery wouldn’t help because you would still be charging it from the main battery due to the issues raised by @Jason Bourne.
Depending on how sensitive it is, adding a draw to an existing circuit may cause an alert to trigger because it is drawing more than it is supposed to.
No, because you would plug it into to something like the 12v accessory outlet that is intended for such purposes.
Now you got me doubting whether I should hook my camera up directly to the battery. On previous cars I used the power magic pro to cut off the camera below a certain voltage or after a certain amount of hours and was excited to have always on cam :/
Anyone else who hooked directly to battery having these issues?
Anyone else who hooked directly to battery having these issues?
Considering the next generation of Teslas probably won't even have a 12v battery, the Model 3 may be a good "practice" car for wiring constantly powered dashcams. If Tesla is indeed monitoring the power of the 12v battery that closely that they can see a dashcam and have it cause issues with their monitoring, then it's pretty clear that the old method is no longer valid. If I wanted my dashcam powered constantly, then I would definitely get the BlackVue battery pack. This gives the dashcam it's own dedicated power source. Simply plug it into the 12v power socket or hard wire into the red wire on the passenger side. The only downside to this appears to be the added cost and the fact you only get about 12 hours of power before you need to driving again to recharge it. Hopefully they can come out with a unit that has a bigger battery to give you longer run times (or maybe somebody can crack one open and figure out if it's easy to add additional battery capacity). I also found another unit which is similar, bigger battery and also surprisingly expensive too.
For me, I wired mine into the heave gauge red wire on the passenger side. Whatever is powered on that circuit does not seem to care about a dashcam (it's use is probably so low compared to the main load that the monitoring system just doesn't notice). Overall, the Model 3 was one of the simpler cars for me to wire into. I also used a bolt that hold part of the trim in place for the ground. The less I have to tap into factory wiring, the better!
For me, I wired mine into the heave gauge red wire on the passenger side. Whatever is powered on that circuit does not seem to care about a dashcam (it's use is probably so low compared to the main load that the monitoring system just doesn't notice). Overall, the Model 3 was one of the simpler cars for me to wire into. I also used a bolt that hold part of the trim in place for the ground. The less I have to tap into factory wiring, the better!
Jason Bourne
Member
Yes. I cut the two lower strips of black tape that wrapped around the white plastic tray to give me easier access to all the loose wring in there. There you'll find a very thick red wire that stands out from the rest (you can see it in the picture). This is the switched 12v. It can stay on for a bit after you leave the car, but its always on when driving. I simply cut off some of the insulation using a utility knife (being careful not to cut any of the copper strands of wire or nick surrounding wirinig). I was then able to insert my dashcam's power wire into the middle of the red wire's cooper strands. I wrapped the spot up with electrical tape to protect it and hold the dashcam's power wire in place as well. I didn't want to use a tap because that could compromise the integrity of the wire and considering how thick it is, I'm sure it carries a lot of power.
And please note after I tapped into this, the power goes through a fuse before going to the dashcam itself. Considering how many amps that circuit probably supports, if I didn't have the fuse and the dashcam somehow shorted out, the thin wiring going to it would become a fuse (major fire risk).
And please note after I tapped into this, the power goes through a fuse before going to the dashcam itself. Considering how many amps that circuit probably supports, if I didn't have the fuse and the dashcam somehow shorted out, the thin wiring going to it would become a fuse (major fire risk).
Dag
Member
Picked up my car today from service for minor items concerning the door windows. I noticed an extra line item on my service report concerning the 12v battery. They never mentioned the work done or the swap of the battery until I picked up the car. The Blackvue has been connected to the 12v battery since January and the car never had an error concerning the battery. It would have been nice to have been talked to before removing items that were not part of the original work order...
Concern: Customer: Remote diagnostics show that this vehicle's 12V battery is in need of an
urgent replacement due to frequent overcharging.
Corrections: Battery - Auxiliary - 12V
Verified customer concern, recommend replacing 12 volt battery. 12 volt battery replaced,
verified alert is no longer present. *** NOTE -Technician noticed aftermarket wiring to
positive battery cable ****
Concern: Customer: Remote diagnostics show that this vehicle's 12V battery is in need of an
urgent replacement due to frequent overcharging.
Corrections: Battery - Auxiliary - 12V
Verified customer concern, recommend replacing 12 volt battery. 12 volt battery replaced,
verified alert is no longer present. *** NOTE -Technician noticed aftermarket wiring to
positive battery cable ****
You may be thinking of alternator load dump. If the car is running, and the battery is being charged such that the alternator is at full output power, and then the battery ground is disconnected, the alternator output causes a large (>100V unless suppressed) voltage spike until the alternator controller can turn it off and/or the field collapses. All OEM modules are build to withstand the spike, but aftermarket may not be. If a device were connected to the ground post such that it was the only thing still connected, it would only see the battery voltage due to being isolated from chassis ground. Similarly, if the ground strap were disconnected, the starter would not work, and the new device would be the only thing running. Interestingly, on some cars with incandescent brake lights, the brake light circuit can function as a backup for the engine control computer ground (at least until you push the brake pedal... wire was eaten by rodent)
Ground loops are caused by having multiple ground paths between equipment. Commonly found in audio gear with grounded AC plugs and unbalanced RCA type interconnects. A device with a single ground wire cannot have a ground loop. You can have a ground offset if there is a high current device sharing the same return path. All HV circuits on an EV are fully isolated from the chassis. The highest continuous draw items are HVAC fan and rear defrost. Intermittent high draws are wipers and window motors.
There really should not be a wiring issue that requires the ground line to be fused. To be useful, the ground path resistance would need to be high enough to not blow the bad circuit's fuse and yet low enough to have enough current to blow the ground fuse. If that happened, you would have a ground circuit at battery potential, not as big a problem as AC wiring, but still not typical. Device may not like it much and could cause its outputs to go into undefined states/ leak/ activate.
All good points, but I was specifically addressing ground strap situation and the starting of the car. (Wasn't aware of the voltage spike problem. Good to know!)
Let's say you install a device that is grounded to the frame in some way, for example a new radio where the antenna cable shield is grounded at the antenna. If the negative side of the device is connected to the battery, and the heavy strap between the battery and the chassis comes loose, then the only remaining connection between the negative of the battery and the chassis (where the negative side of the starter is connected) is through your new equipment. Without a fuse on that negative wire, the starter will try to pull several hundred amps through what is certainly not designed to carry it. Worse, if the device itself isn't grounded, but a down-stream component is, all that extra stuff is also in the high current ground path.
Relying on the chassis ground for the device power return creates the opportunity for a ground loop, since various parts of a car's chassis may have different bonding points. This isn't a problem for DC devices (lamps), but if you're installing a radio device, it can be a problem. So, the best practice is to get power from the battery directly, and fuse both lines.
Ah, yah everything you mention makes sense for a radio install with a second ground path. I was only thinking of the dash cam situation.
Kenriko
Former Vendor
SomeJoe7777
Marginally-Known Member
I'm scheduled to have Johnny from Calibred Customs install a BlackVue 750S in my M3 next week here in Houston (yes, they are California-based, but periodically send techs out to do work elsewhere). I'll ask him about the 12V constant power issue. I have a feeling I'll probably have to go with the Power Magic Battery Pack to avoid connecting directly to the 12V battery.
Akikiki
A'-Lo-HA ! y'all
I agree with you concerning using the body as a ground. But I take it an extra step. There is so much about the Tesla that we do not know reference when grounded wires at still carrying current. Loosening an existing ground (screw/bolt/nut to slide another ground terminal into the group could cause the spark of electricity to jump. I've seen it, when the car had not sit long enough to turn itself completely off. When I am making a ground on my Tesla, I drill a new hole in a metal internal panel and use a self-threading screw to get a new contact to the body. I'm not going to debate someone if it necessary or practical or even a safe guard. I take care not to drill though something that's going to puncture a hose, wire or harness. If I can't get to the backside to find what I am going to hit, then I find another spot to drill. This simply in my opinion is going to lessen the risk. And on the 12v positive side, I add another inline fuse to safe guard the device.
