Constant drain of car battery due to my hardwired dashcam?

GermanCivic

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Hello guys,

I've recently built a dashcam into my 2017 Civic sedan. I'm not owning a garage, that's why I also want to protect my car with the so called parking mode.

I used a hardwire kit, which goes into the fuse box, so the dashcam gets constant power, even if the car is off. The hardwire kit should prevent the car battery from fully discharging, so I assume it cuts the dashcams power off when the car battery has less than 11.6 Volt.
Honda Civic 10th gen Constant drain of car battery due to my hardwired dashcam? 6f39c7e9-8b42-42ae-a0b9-c2bdf1e5275f_1.88d2f2a02dcc66a230c91bd40e149e31


With the myhonda-App I could see that after several hours of parking the battery voltage droped from 12.8 volts to 12.2 volts (I know there are different time and date on the pictures)
Honda Civic 10th gen Constant drain of car battery due to my hardwired dashcam? IMG_2019-03-18_17-16-14.JPG


So the big question is, how much I'm damaging my car battery if the voltage goes permanently down to less then 12 volts or even 11.6 volts.

The dashcam model is Viofo A129 duo, if anybody wants to know. :)

Thanks
 

calonzo

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Have you seen it go lower than 12V?

There will always be some voltage drop immediately after shutting off your car because the battery is adjusting to not being charged constantly by the alternator.

You should compare the voltage drop with the dashcam disconnected to see if it is only due to the dashcam, and not normal for the car.
 

davidgostbo

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I think 11.6 is way too low, typically you don’t want car batteries to go low or else it’ll deep cycle, I did that and had to replace battery within a year. Might be a bit costly but I’d just buy a battery pack for the dashcam
 


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I love the Blackvue. No issues. I also ordered the small 2 foot cable so I can have my rear cam mounted by the rear view mirror. It sees the rear just like looking in the mirror and I don't have to run 30 feet of cable. Car is tinted and I can't mount on glass or won't anyway. Here no cars have front plates.

And i carry one of those items where I can self jump start my car. You can get them off Amazon. Worth the money. In reality, I have only used it to jump start large vans at wife's daycare place. Used three times and still could do more. Do you really want to be a good samaritan and allow a stranger to put jumper cables under your hood? My other car the battery was hidden and hard to get to, so this way if someone needs a jump I can accommodate. They are small. I carry that and an air pump in the boot. Always being prepared.

Perhaps something like this?
Honda Civic 10th gen Constant drain of car battery due to my hardwired dashcam? 615kmzLyP7L._SL1000_
 
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GermanCivic

GermanCivic

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@kg4fx
That's a great idea, I already thought about buying such a device.
Actually I'm carring jumper cables in my trunk. But when the battery is dead, I first have to find and pick up some kind of car sharing vehicle from Drive Now, Car2go or similar but those are obvisoulsy not avaliable outside of cities.

@all
I wonder what actually happens to the Honda system and the head unit if the battery is dead or will get disconnected. I would assume the Civic will start a recalibration process? Did anybody here ever tried out?
 
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davidgostbo

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@kg4fx
That's a great idea, I already thought about buying such a device.
Actually I'm carring those emergency car ignition wires in my trunk. But when the battery is dead, I first have to find and pick up some kind of car sharing vehicle from Drive Now, Car2go or similar but those are obvisoulsy not avaliable outside of cities.

@all
I wonder what actually happens to the Honda system and the head unit if the battery is dead or will get disconnected. I would assume the Civic will start a recalibration process? Did anybody here ever tried out?
Everything’s fine headunit still saves everything which is nice. But it does start the recalibration process like looking for gps
 

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Hey man, do you like the Blackvue dash cam? I am looking into https://www.blackboxmycar.com/colle...vue-dr590w-2ch-dash-cam?variant=6844741287991 myself but just want to make sure they work before jumping the gun.
I have the blackvue 750s-2ch dash and while it works perfectly I wouldn’t recommend it. It’s super overpriced imo and not that good picture quality. I really wouldn’t recommend that dash cam you’re looking at it’s overpriced. If I hadn’t bought my dashcam I highly highly recommend the viofo a129 duo. Look up YouTube videos comparing the picture quality between it and blackvue it’s way better and much cheaper :)
 

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This is from a table off an RV website...

12.6 volts = 100%
12.5 volts = 70%
12.3 volts = 50%
11.4 volts = 20%

...and this is for marine batteries which it's undesirable to discharge more than 50% for long battery life. Starting batteries will do far worse. Expect your battery to live a short life (months... maybe a year. Start taking it down flat and it may not come back after a few of those) and replace it with whatever has the highest reserve capacity as possible, in the largest size that will fit in the tray. I think we can take one that's slightly taller and still allow the hood to close. A much better solution is to buy a stand alone Lion battery pack.

I looked up a good 51 series battery that fits in our car. I think your battery is junk with poor capacity... a few numbers...

https://shop.advanceautoparts.com/p...8-P?navigationPath=L1*14920|L2*15000|L3*15597

Here's one of the few batteries carried for our cars at Advance. I just picked the gold one.

Reserve capacity is 85 minutes.

Reserve capacity is a 25A load until you're 'flat'... pretty sure they pick 10.8 but I can't remember the exact value. Anyways... 12v at 25A is 300 watts.

85 minutes x 300 watts is 25500 watt/minutes

The supply is 1.5A at 5V... which comes 7.5w of draw... assuming it actually uses all that is supplied.

That means 25500 watt/minutes / 7.5 watts means 3400 minutes to making a battery 'flat' that is about as good as you can get for our starting battery. 3400 min / 60 min/hr comes out to just under 57 hours.

There more to consider... the other minor draws the car has, though it should go a month or more without killing the battery. The fact the lower the draw, the more you get due to less losses from the batteries internal resistance. Whether or not the draw is actually all of the 1.5A that power supply provides (it shouldn't be... though it could be a sizable fraction).

What does all this mean? If you should be able to get over 2 days until a battery in good condition was dead... assuming the draw is as large as it could possibly be and the capacity is as low as it possibly could be means that your battery using over 1/2 it's capacity in just part of a day to power this thing has very poor capacity already.
 


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Have you seen it go lower than 12V?
No, I haven't yet.


You should compare the voltage drop with the dashcam disconnected to see if it is only due to the dashcam, and not normal for the car.
True, that was a good advice, so I tried it out:

The battery went from 12.7 to 12.5 volt after 15 hours of parking, while the dashcam was off.

Today the dashcam kept running in parking mode (10fps) for a 8 hours parking time and it went from 12.7 to 12.3 volt.




By the way the Viodo A129 has a 2.43 watt power consumption with the timelapse parking mode (10fps recording):
Honda Civic 10th gen Constant drain of car battery due to my hardwired dashcam? 20190317_210730-1008x756
 

charleswrivers

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No, I haven't yet.




True, that was a good advice, so I tried it out:

The battery went from 12.7 to 12.5 volt after 15 hours of parking, while the dashcam was off.

Today the dashcam kept running in parking mode (10fps) for a 8 hours parking time and it went from 12.7 to 12.3 volt.




By the way the Viodo A129 has a 2.43 watt power consumption with the timelapse parking mode (10fps recording):
20190317_210730-1008x756.jpg
Cool. So you should get 3x the time I spoke about on a good battery... about a week.

BTW... a resting battery at 12.5 is a good 10-20% off of full capacity. If you're going to keep with your starting battery to run it, you've got to be doing a bit of driving to allow the alternator to recharge it. If you're short tripping it, it's not going to get back to full charge. Alternators don't reach their rated output until you're something like 2000 RPM on the engine (should be a 3:1 to be around 6000 on the alternator.

I think your OEM battery is a mix of poor design capacity with not all of it left at this point. If you're running that camera, keep a set of jumper cables handy. 11.6v may be marginal to get a crank.

When your battery does eventually die, make sure you get a good replacement. It's a good possibility you'll be free replacements inside their 3 year periods if you're cycling them a lot to run that camera.
 
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GermanCivic

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This is from a table off an RV website...

12.6 volts = 100%
12.5 volts = 70%
12.3 volts = 50%
11.4 volts = 20%
That seems kind of similar from what I've read recently about car starter batteries:
>12,8 V fully charged
ca. 12,4 V normal
ca. 12,2 V weakly loaded
ca. 11,9 V normal discharged
<10,7 V deeply discharged

Now the most interesting thing for me to know would be, how much is enough to start the Civic properly? Some old cars without all the electronic functions managed to start with 10 volt or less.


I think your battery is junk with poor capacity...
Why exactly do you think that, only because it's loosing voltage so fast? Please do not forget it's actually cold outside, something like 3 or 4 degree celsius.


If you're going to keep with your starting battery to run it, you've got to be doing a bit of driving to allow the alternator to recharge it. If you're short tripping it, it's not going to get back to full charge. Alternators don't reach their rated output until you're something like 2000 RPM on the engine
I'm actually short tripping, driving 30 minutes through town (15 kilometers = 9 miles), most of the time not far above 2000 RPM.


I think your OEM battery is a mix of poor design capacity with not all of it left at this point.
My car is parked outside too far away, if not I would have had a look at the battery and tell you the brand and capacity. It's only one year old and has 20,000 Kilometerstand (12,500 miles).

If you're running that camera, keep a set of jumper cables handy. 11.6v may be marginal to get a crank.
Actually I'm carring jumper cables in my trunk. But when the battery is dead, I first have to find and pick up some kind of car sharing vehicle from Drive Now, Car2go or similar but those are obvisoulsy not avaliable outside of cities.
But soon I will buy such a little power bank which has the cables and capacity to jump a car.


When your battery does eventually die, make sure you get a good replacement. It's a good possibility you'll be free replacements inside their 3 year periods if you're cycling them a lot to run that camera.
I'll do that for sure, my last battery survived 7 years until I sold the car. It lasted for 90,000 kilometers (56,000 miles) and there were some serious winters and a lot of short tripping.
 

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Why exactly do you think that, only because it's loosing voltage so fast? Please do not forget it's actually cold outside, something like 3 or 4 degree celsius
The cold definitely has a huge effect on capacity. It's probably only delivering about 1/2 it's reserve capacity at those temperatures. It still should do better. Some numbers:

I base it on 8 hours going from 12.8 to 12.3. 12.7 resting (no load) is actually about what a fully charged battery. Assuming 12.3 is around 50% capacity... 2.43w at 8 hours (I'll keep it in watt-minutes for the above numbers comparison)... that works out to 1166 watt-minutes.

1166 watt-minutes/25500 watt-minutes of a good battery I linked from the store should be only about 5% capacity of a battery in warm weather. 10%... of temperature corrected capacity, assuming you only have 1/2 capacity in cold weather. Your voltage numbers look like it discharged 10x faster (warm) or 5x faster (cold). At that trend, 8 more hours would have made the battery pretty much totally drained. The voltage should drop very slowly holding kind of linearly and then start to plummet as the weakest cell(s) start to fall.

Once you reverse cells, voltage plummets to the point the battery is virtually unusable and that reversed cell is a load onto the rest of the cells. You can charge it and try to bring it back... but they never come back quite and good... and they don't have a lot of times in them before they just don't want to come back.
 
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@charleswrivers
Alright, thanks for all your detailed answers.
It now seems to me that my nextbase hardwire kit adapter, which cuts the dashcam off when the starting battery has 11.6 volt, is miserably built, because it should cut the power of the dashcam much ealier.

One last question, what do you think should be the lowest point, I should drain my battery, to not damage it too fast, is 12.3 already too low?


I have the blackvue 750s-2ch dash and while it works perfectly I wouldn’t recommend it. It’s super overpriced imo and not that good picture quality. I really wouldn’t recommend that dash cam you’re looking at it’s overpriced. If I hadn’t bought my dashcam I highly highly recommend the viofo a129 duo. Look up YouTube videos comparing the picture quality between it and blackvue it’s way better and much cheaper :)
You're right the A129 duo is cheaper and the video quality at daylight and also at night is better but I think the Blackvue 750s 2channel has a much better parking mode, from what I have heard.
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