Partial answer to "How long can I safely run my camera on the battery"

DAP

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Dash Cam
Two Viofo 129 PRO cameras and a Tesla Model 3 4 Channel
I just measured the power of two different dash cams. One draws 2W, the other 1.6W (the 1.6W is an A119, other one is a bit older).
Lets go with the 2W one to be conservative.
Assuming 80% efficiency of the voltage regulator in the cigarette lighter plug, we get 2.5W drawn from the battery.
Assuming 12V, you are drawing 208 mA from the battery.
My cars battery has 100 minutes of reserve capacity. This is defined as how long can you draw 25A from the battery before its voltage drops below 10.5V
We will assume this is a good estimate of the ampere hour capacity of the battery (since this specification is not given), and we get 41.6 AH.
Lets assume we don't want to drop the battery below 50% charge (so we can still start the car at the end of this), and we get 100 hours, or 8.3 days.

Note also that the battery is driving a bunch of other electronics while the car is parked, so it will actually drain a bit faster, but it is probably safe to leave the camera running over a weekend.
 
If you allow the battery to drain to 10.5v then the battery will deep cycle and may never recover. That's extremely too low. The car probably won't start with that low of a voltage. 12v-12.2v would be minimal.

Sent from my SM-G965U using Tapatalk
 
If you allow the battery to drain to 10.5v then the battery will deep cycle and may never recover. That's extremely too low. The car probably won't start with that low of a voltage. 12v-12.2v would be minimal.
That is why I used only half the AH value so the battery is only half discharged.
 
Your biggest error is in assuming that the battery starts off 100% full. Although a lead acid battery can charge pretty fast if it is at 50% full, by the time it gets to 90% it can only be charged slowly, and a normal car alternator will charge it very slowly over the last 10%, much slower than a battery charger. Probably needs a 12 hour drive to reach 100% from running a dashcam for 24 hours.

So if you are taking it down to 50% before cutoff, and driving for 1 hour per day, you will probably be starting at around 70% charge, meaning you only have around 20% of the rated power available.
 
Your biggest error is in assuming that the battery starts off 100% full. Although a lead acid battery can charge pretty fast if it is at 50% full, by the time it gets to 90% it can only be charged slowly, and a normal car alternator will charge it very slowly over the last 10%, much slower than a battery charger. Probably needs a 12 hour drive to reach 100% from running a dashcam for 24 hours.

So if you are taking it down to 50% before cutoff, and driving for 1 hour per day, you will probably be starting at around 70% charge, meaning you only have around 20% of the rated power available.

You will note that it takes 8 days of running the camera on the battery alone without re-charging to drop from 100% to 50%, so if you drive the car an hour a day you will never get close to dropping down to 50%.
 
You will note that it takes 8 days of running the camera on the battery alone without re-charging to drop from 100% to 50%, so if you drive the car an hour a day you will never get close to dropping down to 50%.
But you will always be closer to 50% than 100% because the battery charges so slowly as you get nearer to 100% that you never get near 100% with only a 1 hour charge.

Realistically it is more like 2 days than 8 days.
 
You forgot to factor in the drop in temperature at night.. and that each night probably has a different temp. Then.. there is the wind, phase of the moon and elevation as well as how high your camera is in relation to the battery.. pushing all those electrons uphill takes some doing. Also.. and this is almost insignificant.. but is your vehicle aligned with the magnetic force field... electrons flow with less resistance going along the force field rather than across it. :D
 
You will note that it takes 8 days of running the camera on the battery alone without re-charging to drop from 100% to 50%, so if you drive the car an hour a day you will never get close to dropping down to 50%.

Go ahead and try this. Have your jumper cables ready because you're going to need them :oops: My big old American van has a huge battery compared to most cars, and even when it's been topped off with a slow-charge the very best it can do is run one cam for about 40 hours if it's going to have enough juice to start (and less under worse conditions). I learned this the hard way, and more than once due to my forgetfulness. The only meaningful numbers here is what voltage you think is as low as you can tolerate. Heat and cold, battery age and condition, percentage of charge at the beginning, the batteries discharge characteristics- all this and more make paper calculations worthless here :(

On this website at least, I probably have as much experience as anyone else with recording on my cam(s) continuously without any form of timer or BDP. That experience has been spread across 3 different vehicles as well, along with brand new batteries and ones which were at the end of their useful life. And that has been with having from one to five cams going :p I once ended up with a no-start after just 2 hours of parking (4 cams, old battery, hot weather, and undercharged battery) yet I'd done 4 hours with the exact same set-up a few weeks before; both times unintentionally. I'm currently running 2 cams and seeing about 20 hours before cranking speed lowers noticeably, which is definitely doing a bit of damage to my battery, so I don't let it go that far.

I may not have the numbers but I have the experience, and I willingly share it because when I got into this game everyone here said that recording more than a few hours without a BDP was probably going to destroy my battery quickly. I couldn't afford the device, so I took it upon myself to be the guinea-pig for all and to see what actually happened. Four years later now and I'm certain of my results- and I still run cams continuously without a BDP but I still recommend using one even if just to save you from one moments forgetfulness.

But please do try your theories and let us know what your results are, as I've done. I firmly believe in having plenty of data in making decisions and recommendations and your input will be nice to have on hand whether it coincides with mine or not :cool:

Phil
 
A hybrid deep-cycle car battery will significantly increase the run time of any hardwired dash cam setup.

https://www.batteriesplus.com/productdetails/sli48agmdp

These run $300, pretty pricey, but a simple way to eliminate short run times without having to deal with 2nd battery/isolator circuits. My car's custom storm chasing equipment circuit pulls 5 amps, and I once left it on for nearly 2 days without draining the battery. My old stock battery would drain in 5 hours pulling that much current. For a one or two dashcam setup, it would probably run for 2 weeks.
 
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A hybrid deep-cycle car battery will significantly increase the run time of any hardwired dash cam setup.

https://www.batteriesplus.com/productdetails/sli48agmdp

These run $300, pretty pricey, but a simple way to eliminate short run times without having to deal with 2nd battery/isolator circuits. My car's custom storm chasing equipment circuit pulls 5 amps, and I once left it on for nearly 2 days without draining the battery. My old stock battery would drain in 5 hours pulling that much current. For a one or two dashcam setup, it would probably run for 2 weeks.

Odyssey is supposed to be the best but hard to find in stores. Optima Yellow Top is easier to find but lower capacity. Sam's Club sells Duracell AGM batteries but you have to be a member of Sam's Club
 
A hybrid deep-cycle car battery will significantly increase the run time of any hardwired dash cam setup

That alongside the regular battery with a charge / discharge splitter would be my optimal setup, but as i will only use parking mode < 1 hour at a time i will be going with the conventional solution.
But if you want to use your car as a mobile CCTV camera / spy solution, for long periods, then the quoted solution are hard to beat.
 
I think it's much easier to simply add another AGM battery w/box, breakers, wiring buss, etc, and beefing up the alternator, or even adding an additional alternator. Today's electro-gizmos are not the crude stuff of 30 years ago. New vehicles are practically science fiction, compared to a '57 Chevy. The OEM alternator in most cars is nothing but a glorified "trickle" charger/maintainer, just to keep the Factory's battery vendor in business with a just good enough battery. Many car makers have those "Smart" alternators, all connected to CAN bus, etc. They have awful "charging" capability.
 
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