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Dashcam Install Help

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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.

Good point on active circuits and removing their grounds.

With these new holes, are you using stainless steel screws or something else to prevent galvanic corrosion down the road? (Assuming even interior panels get the sea breeze salt exposure)
 
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.
It's been so long since I purchased it, I don't even remember what the Power Magic Battery pack does.
 
It's been so long since I purchased it, I don't even remember what the Power Magic Battery pack does.
Not sure if you were making a point or actually asking. In case it's the latter, it's pretty much a battery that can power your camera for 12 hrs in parking mode and not affect your actual car battery. It charges when you turn your car on and drive, according to BlackVue, it takes an hour to charge fully.
 
The problem seems to be ‘always on’ dashcam power. Instead of hardwiring the BlackVue ‘always on’ why not hardwire the Blackvue Power Magic Pro the same way and plug the dashcam into that. Then set a shorter time period for the camera to stay on in parking mode. You have multiple choices from 6 hrs to infinity. I have mine set for 6 hrs. The camera powers off after that set time. That covers 99% of my away from home parking (retired). Need longer then set 12 hrs. or more. Bottom line is the camera will power off after that time.
 
The problem seems to be ‘always on’ dashcam power. Instead of hardwiring the BlackVue ‘always on’ why not hardwire the Blackvue Power Magic Pro the same way and plug the dashcam into that. Then set a shorter time period for the camera to stay on in parking mode. You have multiple choices from 6 hrs to infinity. I have mine set for 6 hrs. The camera powers off after that set time. That covers 99% of my away from home parking (retired). Need longer then set 12 hrs. or more. Bottom line is the camera will power off after that time.

I don't think that's going to help the situation. The root cause of the 12V battery errors that people are getting seem to be that the Model 3 is carefully auditing the amount of power that's leaving the 12V battery vs. the battery's terminal voltage to determine whether the battery is in good health or not. Any power that leaves the 12V battery that isn't going through the Model 3's auditing process is reducing the 12V battery terminal voltage more than the Model 3 is expecting. The Model 3 interprets this as the 12V has an internal short or lack of capacity and flags it as a bad 12V battery.

As an example, let's say the 12V battery is a standard lead-acid and is 20 Ah capacity (240 Wh). The terminal voltage is 13.8V when fully charged, and 12.5 volts when half discharged - a 1.3V swing. The Blackvue draws 350 mW, so over a 24 hour period, that's 8.4 Wh. By ratio, 8.4/120 * 1.3 = 0.091 V. If, over a 24 hour period, the Model 3 sees 60 Wh leave the battery for the Model 3's own systems, it would expect a 60/120 * 1.3 = 0.65 V drop in terminal voltage for a healthy 12V battery. But with the Blackvue drawing extra power that isn't counted, the voltage actually drops 0.65 + 0.091 = 0.741 V. The Model 3 thinks that the 12V is not performing properly, and throws the error.

Whether you use the Power Magic Battery Pack or not is irrelevant, the problem is hooking it directly to the battery posts because that means its power isn't counted/audited by the Model 3. If you plug it into the 12V power outlet in the console, that will solve the problem because the 12V power outlet is audited.

For a permanent connection to either the Power Magic Battery Pack or the Blackvue directly, we have to find a place to get 12V continuous power that's on the audited side, not directly from the battery posts. That way the Model 3 will know that power is coming out of the 12V and the drop in terminal voltage will then be expected.
 
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I don't think that's going to help the situation. The root cause of the 12V battery errors that people are getting seem to be that the Model 3 is carefully auditing the amount of power that's leaving the 12V battery vs. the battery's terminal voltage to determine whether the battery is in good health or not. Any power that leaves the 12V battery that isn't going through the Model 3's auditing process is reducing the 12V battery terminal voltage more than the Model 3 is expecting. The Model 3 interprets this as the 12V has an internal short or lack of capacity and flags it as a bad 12V battery.

As an example, let's say the 12V battery is a standard lead-acid and is 20 Ah capacity (240 Wh). The terminal voltage is 13.8V when fully charged, and 12.5 volts when half discharged - a 1.3V swing. The Blackvue draws 350 mW, so over a 24 hour period, that's 8.4 Wh. By ratio, 8.4/120 * 1.3 = 0.091 V. If, over a 24 hour period, the Model 3 sees 60 Wh leave the battery for the Model 3's own systems, it would expect a 60/120 * 1.3 = 0.65 V drop in terminal voltage for a healthy 12V battery. But with the Blackvue drawing extra power that isn't counted, the voltage actually drops 0.65 + 0.091 = 0.741 V. The Model 3 thinks that the 12V is not performing properly, and throws the error.

Whether you use the Power Magic Battery Pack or not is irrelevant, the problem is hooking it directly to the battery posts because that means its power isn't counted/audited by the Model 3. If you plug it into the 12V power outlet in the console, that will solve the problem because the 12V power outlet is audited.

For a permanent connection to either the Power Magic Battery Pack or the Blackvue directly, we have to find a place to get 12V continuous power that's on the audited side, not directly from the battery posts. That way the Model 3 will know that power is coming out of the 12V and the drop in terminal voltage will then be expected.

Due to the mention of 'overcharged' in the service write ups, I think a more root issue is that any additional load on the battery (monitored or not) causes the battery to drain faster than expected, need recharging more often, and throws a fault. Having the dash cam on the monitored side would also throw a fault due to a higher sleep current than expected.

Best solution would be a dash cam backup battery that charges from 12V outlet (cigarette socket) when the car is on. Can be as simple as a diode, fuse, and resistor in series to an SLA battery from Amazon.
 
Due to the mention of 'overcharged' in the service write ups, I think a more root issue is that any additional load on the battery (monitored or not) causes the battery to drain faster than expected, need recharging more often, and throws a fault. Having the dash cam on the monitored side would also throw a fault due to a higher sleep current than expected.

Best solution would be a dash cam backup battery that charges from 12V outlet (cigarette socket) when the car is on. Can be as simple as a diode, fuse, and resistor in series to an SLA battery from Amazon.

Well, there's a couple of possibilities. "Overcharged" may not be the right term. The Tesla DC-DC converter is tasked with charging the 12V battery, and no matter what the state of charge, it should never overcharge the 12V. So I question the terminology in the service write-up to begin with.

Second, what is the Model 3 doing when it detects that the 12V terminal voltage drop doesn't match the estimated dischage energy? Does it perofrm a normal recharge or does it attempt to perform an equalizing charge or some other corrective charge to try to regain the presumed lost 12V battery capacity? If so, this indeed could "overcharge" the 12V because this extensive type of charge could be applied repeatedly.

Third, while having the dashcam on the monitored side of the battery would (we assume) satisfy the health checks, it would result in the battery being charged more often. Will the Model 3 allow this, or is the monitoring even stricter such that even more frequent charging would cause an error?

Fourth, for these 12V batteries that those in this thread have had replaced, are the 12V batteries actually bad, or does the car just think they are? This would tell us whether the batteries actually have been damaged by overcharging or not.

We currently don't have anyone who has installed a dashcam and has a permanent 12V always-on connection that is on the monitored side, so much of this is speculation at this point. But I believe we can say without a doubt that the 12V monitoring and health system on the Model 3 is far more sophisiticated than in the Model S/X and that this is going to interfere with aftermarket accessory installation until we get some more facts.
 
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Well, there's a couple of possibilities. "Overcharged" may not be the right term. The Tesla DC-DC converter is tasked with charging the 12V battery, and no matter what the state of charge, it should never overcharge the 12V. So I question the terminology in the service write-up to begin with.

Indeed, I'm taking it to mean "charged too often" (compared to expected).

Second, what is the Model 3 doing when it detects that the 12V terminal voltage drop doesn't match the estimated dischage energy? Does it perofrm a normal recharge or does it attempt to perform an equalizing charge or some other corrective charge to try to regain the presumed lost 12V battery capacity? If so, this indeed could "overcharge" the 12V because this extensive type of charge could be applied repeatedly.

I doubt they have an anit-sulfation or equalization charge that kicks on at such a low number of hours.

Third, while having the dashcam on the monitored side of the battery would (we assume) satisfy the health checks, it would result in the battery being charged more often. Will the Model 3 allow this, or is the monitoring even stricter such that even more frequent charging would cause an error?

I think it would fail the vehicle heath checks due to increased current. It may not set a bad battery fault since the more frequent charging has a known cause. If it is an "overly frequent charge" fault, that would still happen.

Fourth, for these 12V batteries that those in this thread have had replaced, are the 12V batteries actually bad, or does the car just think they are? This would tell us whether the batteries actually have been damaged by overcharging or not.

Given no reports of people with "bad" batteries (other than those where the car drained it completely which I think is a different issue) who did not have a dash cam installed, and that the vehicles did not throw faults until after the install, I'm inclined to go with the batteries were good.

We currently don't have anyone who has installed a dashcam and has a permanent 12V always-on connection that is on the monitored side, so much of this is speculation at this point. But I believe we can say without a doubt that the 12V monitoring and health system on the Model 3 is far more sophisiticated than in the Model S/X and that this is going to interfere with aftermarket accessory installation until we get some more facts.

Most agreed! It may never be possible to add always on accessories without their own backup power source.
 
A friend of mine (who had the dashcam installed by the same guys) sent this over. He got this from the Dublin SC who recommend that he used a proper switch/relay...any idea what they are referring to?

IMG_3771.JPG
 
A friend of mine (who had the dashcam installed by the same guys) sent this over. He got this from the Dublin SC who recommend that he used a proper switch/relay...any idea what they are referring to?

View attachment 289535

They tapped into a monitored always on circuit. The system dislikes any current draw higher than normal when off. I think the suggestion was to use the switched feed (lighter or usb) to switch a relay with a feed from the battery. It is still switched, but would allow a higher current that the lighter plug. It may still trip a fault during operation, depending on the HW/SW monitoring.
 
I agree. We always do this on audio installs. The fuse is there to protect the wire - not the component. (Well actually, the fuse protects the car from the wire.) If the wire gets damaged or accidentally shorts it could turn the wire into a light bulb filament :) Remember to get the right fuse.

What would be the right fuse for his install? I'm asking both for the direct to 12V battery connection, as well as for the switched connection.
 
Here is a table with gauge based on current and length, use a fuse rated less than the wire, and more than the load. Relay coils is < 1Amps, 12 Watt load is 1 Amp. What are you connecting?

Automotive Wire & Wiring Guide from TESSCO - TESSCO.com
Looking to eventually put in a Blackvue system, but I also want to install an LED strip kit, which I plan to take power from a switched source for. I don't want to occupy my 12V outlet with that, so looking for alternatives
 
Yeah, I looked into those. I actually had one in my Taurus way way back... They all seem bulky (not that I'm using that space for other stuff anyway). I thought I could get a "cleaner" looking install if I tap into a wire in the pasanger footwell.

Sure, tapping the feed to the 12V outlet will give the switching signal.. I did a full sound system in my 85 Escort wagon back in the day, but that was not a new shiny 3 :). Could also use a 12V cordset to get the feed and route the wire into the hidden area.