Parking mode power consumption

[wibbly]

Has anyone measured or found the power consumption (in mA) of the A129 Duo in its different parking modes?

 

[Shumi73]

Dashcam consumes around 350mA at 12V (approx 4.2W) in driving mode with WiFi and display off, rear camera connected. And 300mA at 12V (approx 4W) in parking mode with WiFi and display off, rear camera connected. For time lapse and low bitrate in parking mode consumption is still the same.

 

[wibbly]

Thanks

Wow. 4W seems a lot!

 

[Djcham]

Dashcam consumes around 350mA at 12V (approx 4.2W) in driving mode with WiFi and display off, rear camera connected. And 300mA at 12V (approx 4W) in parking mode with WiFi and display off, rear camera connected. For time lapse and low bitrate in parking mode consumption is still the same.

in parking mode dash cam use 4W for every hour? how do u calculate this?

 

[Nigel]

in parking mode dash cam use 4W for every hour? how do u calculate this?

It uses 4Wh per hour, so if you have a 94Wh dashcam battery, and the battery is full, then it will run for 94/4 hours = 23.5 hours.

I would actually expect it to run for a bit longer than that, I think the 4W is a little pessimistic.

 

[wibbly]

0.3A x 12V = 4W. Watts is not "per hour". Probably a better measure for what it would take out of your car battery (if that's what you're using) is 0.35A consumed for an hour = 0.35Ah. Your car battery which has a notional total Ah rating. So if it's a 80Ah battery it would lose an extra 100 x 0.3 / 80 = 0.38% percent of it's capacity every hour. So in theory 9.1% in 24hrs. Bear in mind it won't be starting at 100% capacity and shouldn't be discharged below 50% really. My car maintains it's battery at about 80% as 'fully charged' to make it last longer. So I have around 30% of it capacity I consider "usable".

 

[Nigel]

0.35A x 12V = 4.2W. Watts is not "per hour". Probably a better measure for what it would take out of your car battery (if that's what you're using) is 0.35A consumed for an hour = 0.35Ah. Your car battery which has a notional total Ah rating. So if it's a 80Ah battery it would lose an extra 100 x 0.35 / 80 = 0.44% percent of it's capacity every hour. So 10.5% in 24hrs. Bear in mind it won't be starting at 100% capacity and shouldn't be discharged below 50% really. My car maintains it's battery at about 80% as 'fully charged' to make it last longer. So I have around 30% of it capacity I consider "usable".

Lead Acid batteries vary so much depending on their age and their temperature, and the car they are installed in.

To simplify it, I like to assume that a car battery that gets regular decent charging has around 100Wh available for the dashcam, so 100/4 = 25 hours.

 

[wibbly]

Watt-hour Calculator

Use the watt-hour calculator to obtain watt-hours from amp hours or time.

www.omnicalculator.com

At 12V an 80Ah battery in theory has a 960Wh capacity in total. But you need power to be able to start your car, not trash the battery service life, allow for it not being fully charged at the start, etc etc.

 

[Landbo]

0.3A x 12V = 4W. Watts is not "per hour". Probably a better measure for what it would take out of your car battery (if that's what you're using) is 0.35A consumed for an hour = 0.35Ah. Your car battery which has a notional total Ah rating. So if it's a 80Ah battery it would lose an extra 100 x 0.3 / 80 = 0.38% percent of it's capacity every hour. So in theory 9.1% in 24hrs. Bear in mind it won't be starting at 100% capacity and shouldn't be discharged below 50% really. My car maintains it's battery at about 80% as 'fully charged' to make it last longer. So I have around 30% of it capacity I consider "usable".

Nice to see a person who knows Ohm's law and knows how to treat his starter batteries.

 

[Nigel]

Nice to see a person who knows Ohm's law and knows how to treat his starter batteries.

Ohm's law is about resistance, doesn't really apply to a dashcam, since dashcams use constant power, independent of voltage or resistance.

 

[Landbo]

Ohm's law is about resistance, doesn't really apply to a dashcam, since dashcams use constant power, independent of voltage or resistance.

Well !!!

There must be something you have completely misunderstood as the formula for Watt (P=U*I) is a derivation of Ohm's law (U=R*I).

I would like you to give a few calculated examples of your perception of the effect on dash cams when Ohm's law does not apply there.

 

[Nigel]

Well !!!

There must be something you have completely misunderstood as the formula for Watt (P=U*I) is a derivation of Ohm's law (U=R*I).

I would like you to give a few calculated examples of your perception of the effect on dash cams when Ohm's law does not apply there.

I still say that your dashcam will use the same number of Watts, whatever your battery voltage and whatever the resistance in your cables, so neither of those formulas is of any use in calculating how long the dashcam will run from an eg 100Wh battery. The calculation you need is simply battery Wh / dashcam W, so 100/4 = 25 hours, and I don't see what that has to do with Ohm's law.

If you have a battery that is specified in Ah instead of Wh then you could possibly use Ohm's law in the conversion, but it is much easier to simply use: battery Ah * nominal battery V, so from above 80 * 12 = 960 Wh. Realistically you will never get anywhere near 960 Wh out of a car battery though, even Wibbly's 30% is optimistic! Calculation does work for lithium batteries.

 

[Landbo]

I still say that your dashcam will use the same number of Watts, whatever your battery voltage and whatever the resistance in your cables, so neither of those formulas is of any use in calculating how long the dashcam will run from an eg 100Wh battery. The calculation you need is simply battery Wh / dashcam W, so 100/4 = 25 hours, and I don't see what that has to do with Ohm's law.

If you have a battery that is specified in Ah instead of Wh then you could possibly use Ohm's law in the conversion, but it is much easier to simply use: battery Ah * nominal battery V, so from above 80 * 12 = 960 Wh. Realistically you will never get anywhere near 960 Wh out of a car battery though, even Wibbly's 30% is optimistic! Calculation does work for lithium batteries.

Yes, a 60 Watt light bulb should emit approximately the same light regardless of whether it is made for 230 Volt or 12 Volt. What changes is the consumption in Amps when you measure on them. It is actually Ohm's law that says so and therefore Ohm's law is not only for resistors, although it is the bulb's internal resistance that determines how many Watts it uses at a given voltage. The rest is ordinary arithmetic.

How far down you can discharge a starter battery (lead battery) is only a matter of how short/long time you want it to serve you and how much you can discharge it and still be able to start the engine. Normally, a good rule of thumb would be you never discharge a starter battery below 50% and preferably less.

 

[Nigel]

Yes, a 60 Watt light bulb should emit approximately the same light regardless of whether it is made for 230 Volt or 12 Volt.

If you take your old Danish incandescent 60 Watt 230V bulb and plug it into a USA 120V socket, it will only use about 30W. This is different to a dashcam, which will always use the same amount of power, whatever the voltage, and since the HWK uses a switching regulator, resistance doesn't come into it.

 

[Landbo]

If you take your old Danish incandescent 60 Watt 230V bulb and plug it into a USA 120V socket, it will only use about 30W. This is different to a dashcam, which will always use the same amount of power, whatever the voltage, and since the HWK uses a switching regulator, resistance doesn't come into it.

You keep saying what it isn't. Naturally, a 60 Watt 120 Volt bulb will light as much as every other 60 Watt bulb that is powered by the voltage it is manufactured for.

The internal resistance of the load is actually the one that determines how much power (Watt) a load consumes at a given voltage. This actually also applies to a dash cam, although the load here becomes a complex value as it is a switching PSU that is the load.

 

[Kindly Doctor]

Dear friends, practice shows that a lead-acid battery with a capacity of 80 Ah, discharging from 100% (12.7 V) to full discharge (12 V), produces approximately 35-37 Ah. But such a discharge is destructive for the battery. It is not recommended to discharge it below 12.5 V and leave it in this condition. The recorder wire can limit the minimum voltage to 12.4 V, so on a battery with a capacity of 80 Ah, with a current consumed by the recorder of 300 mA, the voltage drop from 12.7 V to 12.4 V takes about 4-5 hours. Then the recorder turns off. These are not just my observations. With current consumption of 300 mA in parking mode, this mode is not very functional.

 

[wibbly]

Dear friends, practice shows that a lead-acid battery with a capacity of 80 Ah, discharging from 100% (12.7 V) to full discharge (12 V), produces approximately 35-37 Ah. But such a discharge is destructive for the battery. It is not recommended to discharge it below 12.5 V and leave it in this condition. The recorder wire can limit the minimum voltage to 12.4 V, so on a battery with a capacity of 80 Ah, with a current consumed by the recorder of 300 mA, the voltage drop from 12.7 V to 12.4 V takes about 4-5 hours. Then the recorder turns off. These are not just my observations. With current consumption of 300 mA in parking mode, this mode is not very functional.

Agreed. IMHO the only sustainable parking modes are those that consume less than, say, 10mA or so. And in most cases where such a mode is available, startup times mean the camera misses the event it's there to capture :-(

 

[Kindly Doctor]

I think that a current consumption of 100 mA should be sufficient both to provide the functions of the recorder and to ensure that the battery does not discharge to a critical level for at least 10 hours. This could be a solution to the problem if the car is used every day. Perhaps the manufacturer will take these shortcomings into account in its new products, or maybe not.