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Blackvue 750 causing 12V battery warning?

Alphaa

New Member
Mar 22, 2018
1
0
Sydney, Australia
Recently installed a Blackvue 750 2Ch to replace my dead 650. Seems to be working great for the most part, but I did notice that it seemed to increase my phantom battery drain a couple of miles per day, but not sure as the weather is colder so hard to know where to attribute that loss.

However, this evening, I started the car and had the "12v battery needs replacement" warning. While it is entirely possible that it does need replacing, it seems a tad unlikely as it was just replaced about a year ago and my original lasted about 4 years.

I also know that the warning is triggered not by the 12v battery voltage, but by a measure of the amount of charge it is requiring from the traction battery. So if the new Blackvue is causing significant increased draw beyond what the car is programmed to expect it could trigger this.

Just looking to see if anyone else has experienced it. I'm out of warranty so the 12v replacement will be on my dime and if it isn't really necessary I sure don't want to do it...but then I have to figure out when I'll know if/when it really is needed.

Not using a Power Magic Pro, direct connection to continuous power. Am using Parking mode.


I have installed same camera on my previous Porsche Macan, which has only a 12v battery. It doesn’t drain it enough to cause problem, even parked for over 2 weeks
 

eHeyMan

Member
Sep 29, 2015
15
5
WA
11Jul18 - 12V Model 3 Battery replaced @ 5890 miles (car only 5 mo’s old)
15Apr19 - Warning again saying “12V battery needs service - Replace 12V battery soon”. (2nd batt life 9 mo's)
I measured 13.87V, 14.9V, & 14.97V on three separate dates with a voltmeter on 12V battery posts.
7May19 - In for service, replacing 12V battery

Information previously mentioned in this thread worth restating again:

Excellent info here (with design suggestions on fixing/improving 12V battery life) from this article: "Tesla Model S 12V Battery Analysis" by Russell Graves. Syonyk's Project Blog: Tesla Model S 12V Battery Analysis

I find this comment from Russell on June 21, 2017 very pertinent: "The idle draw of the computers is so huge that it dwarfs anything else connected, and there's not a lot you can do short of hooking up a high power battery tender/charger when parked. I have no idea if that will upset the computer or not, and it probably needs to be able to source 4A to keep the battery charged with the draws on it (so your typical little battery tender won't do it)."

Interesting points mentioned in article:
"First, the number of cycles per day is absurd. The car is putting 5 cycles a day on the 12V battery. That's rather high - so that long cycle life rating doesn't mean what it normally does. At 5 cycles a day, a year is 1825 cycles. At 50% depth of discharge... well, that's your battery life and then some."

"The second thing that stands out is those spikes. That's 15.8V - four times in three days. If it were once, I'd write it off as a weird event, but it's quite frequent. It's apparently quite deliberate - it occurs at the end of the charge cycle, and is the final stage before the charger shuts down for a while."

"Lining up from the start of discharge, the discharge interval is pretty constant. It's right in the 2-2.5h range, reliably. At 30W, that's around 60-80Wh, though there are those spikes to higher drains. If I ballpark 40W as an average, that's 80-100Wh per discharge cycle. That's only 25% of the battery capacity, so it should be good for 5000+ cycles per the spec sheet. Obviously, it's not lasting that long."

Note: Average power draw from a typical BlackVue dash cam is 3-6W or 0.25 - 0.5 amps (3 / 12, 6 / 12). Specs from the manual on our BlackVue DR750S-2CH installed in the Model 3 is 4.2W at 12V or .35 amps (or 350 mA) with GPS and Wi-Fi on. https://www.blackvue.com/download/dr750s-2ch-manual-english/

Note: We have also have a BlackVue DR650GW-2CH dashcam installed in our model X (always on). Still on original 12V Tesla battery since new (March 2016).
 
My hardwired BlackVue DR650S-2CH will work for a few months whenever my Model S gets a fresh new 12V battery installed, but then it will stop powering up. My car's 12V battery will last another year or more for the car before it needs replacing, but for some reason the hardwired 12V plug no longer "works" until then. (I can however power the dashcam from the cigarette lighter's 12V no problem). Anyone know why it might be behaving that way? I measure 14V at the hardwired plug, so I'd expect the dashcam to just work... but maybe it's a current draw problem?
 
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David.85D

Active Member
Oct 29, 2016
1,500
1,269
USA
I’ve had a 2ch BlackVue hardwired for years. My first 12V battery finally died at 5.5 years old.

something else is going on with your BlackVue or car.

The 14V is surprising - that voltage is appropriate during the charging phase. But The 12V shouldn’t be getting charged all the time. If it is, maybe you have a high 12V drain somewhere. The normal operating voltage would be 12.4 to 12.6 volts. Normal charging is 13.8 to maybe 14.5 volts.
 
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I’ve had a 2ch BlackVue hardwired for years. My first 12V battery finally died at 5.5 years old.

something else is going on with your BlackVue or car.

The 14V is surprising - that voltage is appropriate during the charging phase. But The 12V shouldn’t be getting charged all the time. If it is, maybe you have a high 12V drain somewhere. The normal operating voltage would be 12.4 to 12.6 volts. Normal charging is 13.8 to maybe 14.5 volts.
That is a good point. My 12V has needed to be replaced 7 or 8 times in the 8 years I've owned the car... (including a few times the first few years of ownership before I got the BlackVue dashcam installed). Sounds like maybe it's a car side issue that's never been resolved?
 

Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,511
4,868
Kaneohe, HI
My hardwired BlackVue DR650S-2CH will work for a few months whenever my Model S gets a fresh new 12V battery installed, but then it will stop powering up. My car's 12V battery will last another year or more for the car before it needs replacing, but for some reason the hardwired 12V plug no longer "works" until then. (I can however power the dashcam from the cigarette lighter's 12V no problem). Anyone know why it might be behaving that way? I measure 14V at the hardwired plug, so I'd expect the dashcam to just work... but maybe it's a current draw problem?
Hardwired? Hardwired from where? Are you using the black plug behind the speaker grille?
 

whitex

Well-Known Member
Sep 30, 2015
6,748
8,574
Seattle area, WA
I've had BV 650/750/900 in all 4 Model S I've owned, starting within couple of days of delivery. They have all been on 24/7 (with parking mode enabled in BV).So far had one 12V battery die at 4.5 years. That same battery gave me a message it needs replacement after 13 months or so, but that message disappeared 2 days later, so I cancelled the mobile tech appointment.
 

xG35

Member
Feb 8, 2016
238
139
Canada
I’ve had a 2ch BlackVue hardwired for years. My first 12V battery finally died at 5.5 years old.

something else is going on with your BlackVue or car.

The 14V is surprising - that voltage is appropriate during the charging phase. But The 12V shouldn’t be getting charged all the time. If it is, maybe you have a high 12V drain somewhere. The normal operating voltage would be 12.4 to 12.6 volts. Normal charging is 13.8 to maybe 14.5 volts.

same. Have it installed since day 1 and never a problem. Hardwired to run 24/7.
 

Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,511
4,868
Kaneohe, HI
No, it’s not hardwired in behind speaker/mic grill… I checked there (had a service shop install it for me, so not exactly sure where the dashcam is getting it’s 12V always on power).

If they wired your BV directly from your battery, its bypassing some of the smarts that the car offers your system. Putting the connection on the "south" side of the batteries electronics lets the car "see" the battery is draining and help manage it such as starting a recharge of the 12V.

Well. We know this works. And we never hear anyone complaining. So, you might want to do this. You are on the receiving side of a lot of trial and error and research for us to figure this out and find the unique parts. Teslatap does an excellent job of documenting mods.
Dashcam Power Cable – TeslaTap
 
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whitex

Well-Known Member
Sep 30, 2015
6,748
8,574
Seattle area, WA
If they wired your BV directly from your battery, its bypassing some of the smarts that the car offers your system. Putting the connection on the "south" side of the batteries electronics lets the car "see" the battery is draining and help manage it such as starting a recharge of the 12V.
Where did you learn this? When I installed the second dashcam, I was shooting the breeze with some techs at Tesla during one of my visits there, and we talked about the drain the dashcam causes (not that much) and they told me the car just monitors the 12V battery voltage and "tops it off" whenever needed. Adding always-on drains to the battery will discharge it faster and cause the recharge cycle to kick in more often. However, given that Tesla can drain the 12V battery completely during standby in just a few hours, a BV dashcam doesn't make that much of a difference. If the car's recharge cycle kicks in more often than expected, the car will notify you that the battery needs changing. Now that was over 5 years ago, so perhaps things have changed, but I'm curious of your source (and maybe some details on how this load monitoring works, whether it's there in all cars or only since some production date, etc).
 
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Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,511
4,868
Kaneohe, HI
Just reading here and there and other scattered sources including talking to Tesla techs. Back when I was installing my first BV in 2013, and had regular access to the techs at the SC they warned me to keep this drain in mind. Yes, I know the BV draws very little. If I had solid reports or explanations I would share and would link to them. Discount my comment if you choose.
 

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