Automatic power + switch for manual power

ArmoredCavalry

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I'm planning to hardwire my dashcam, using add-a-circuit. My original thought was to use my accessory power fuse, which only is powered when the car is turned on. This way the dash camera will turn on automatically when I turned on the car.

However, I'm wondering if there is a way to have the "best of both worlds" so to speak, and wire the dashcam in a way where it will power up automatically when the car does, but also have an inline switch (or something) that gives me the option to turn it on when the car is not powered off (by tapping into another fuse?).

Has anyone done something like this before? Is it even possible without using two separate cables?

Too bad they don't make bluetooth-controlled inline switches, as I could automate it to power up when my phone connects the bluetooth, while still having the option to manually override it (plus turn it on remotely!)
 
Should be easy enough to connect the batt+ wire to a switch and then connect that to an always on fuse using an add-a-circuit. Would need an extra length of cable though.

Was thinking something like this, although I'm not an electronics expert!

Switch.jpg
 
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Well, that gets me a dashcam that can be manually turned on/off right? Doesn't get it to where the default behavior would be to turn on/off with the car automatically (without any action from me).
 
It should because as soon as you turn the car on or off the red ACC(+) wire should take priority and ignore your switch because it's only inline with the yellow BATT(+) wire, which only takes over when the car is switched off.
 
Oh, I see, the key is having the Multi Safer box, which can accept multiple power sources and route them to one basically?
 
Yes sorry I thought I'd read that you had one. I think it would be a little more complicated without one and the Multi Safer would protect your car battery anyway in case you left the switch on for a long time by accident.
 
Oh, nope! That gadget actually doesn't exactly what I need, let's me toggle between acc and constant power. Too bad it is $35, but ah well!

I just was not able to find anything like that when googling. It seems like there are really only two brands that make something like it too.
 
If you don't mind running the risk of leaving it switch on and draining the battery then perhaps this might work, but I'm not 100% sure:

You could buy a cheap hardwire kit for less than $10 on Amazon and run two separate feeds into it using add-a-circuits. You have to use the hardwire kit and not wire directly otherwise you'll be putting 12V straight into the dash cam which will fry it. If you want to go ultra cheap then you can wire into the cigarette adapter that comes with the dash cam by unscrewing the end and tapping into the relevant parts, we've done this for a trial but it's not very attractive or secure.

  • One feed from a fuse which only comes on with the ignition
  • One feed from a fuse which is always on and put the inline switch into this circuit

Both circuits will feed the hardwire kit whilst running the car but the hardwire kit will regulate the output to the camera automatically to 5V and 1.5A. When you switch off the ignition the feed from the always on circuit will still be live but whether or not it allows power into the hardwire kit and onwarwds to your camera will depend on if the inline switch is set to on or off.


So all you need is the following which should be doable for around $15 all in:

x1 Hardwire Kit (12-24V input type)
x2 Bullet Connectors
x1 Butt Connector
x1 Ring Connector (not 100% necessary but neater and more secure for connecting the ground)
x2 Add-a-Circuit (either mini or regular sized blades depending on your car's fuse box)
x1 Inline Switch
x2 pieces of wire that can handle say 5A (speaker wire can be used)


I'd recommend having a multimeter to hand to test outputs at the various points but it would be really good if someone with electrical knowledge could verify if this would work or if it's going to fry the hardwire kit or if it simply won't be able to draw the current properly due to the split? The add-a-circuit fuses will protect your car OEM circuits and the hardwire kit has an inline fuse which should protect your dashcam and also the hardwire box so it should be safe, I just don't know if it will actually work though.

I think the voltage will be in parallel so it should stay at 12V but even if it's in series it will only be 24V which the hardwire kit can handle. I think the current would double if in parallel (remains the same in series) but that shouldn't matter either because of the hardwire kit. Or I could be talking total crap here? lol


Wiring.jpg
 
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This setup was my original thought as well, but, like you said, I have no idea if this would be "safe" or not, ha.

I'm fairly sure this would put the power sources in parallel, which seems to be a bad idea?

Edit: Just realized, technically isn't every fuse really coming from the battery anyhow? So.... it seems like this setup would actually work fine, it would just be two different paths to the same power source?
 
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I'm guessing that with a battery protect it will switch between fuse circuits depending on the state of ignition, but with this setup when the ignition is on there will be both fuse circuits simultaneously providing power to the hardwire device.

If going down this route then I would advice testing the voltage at the butt connector where it would connect to the hardwire kit before connecting it to see what it is and definitely before connecting the hardwire kit to the dashcam. It is fused though so I would assume the cam would be protected but no harm in being cautious.
 
@arcticfire .. you are a real artist!! Love your diagrams!! Thank you!
@ArmoredCavalry ..In trying any of these setups, I would perform a "dry run" with all the pieces laid out on the console and/or floor of the car, and actually connected,, and then perform various ignition on/ignition off tests before tucking in all the wires, etc., along the edges of the car, behind the dashboard, etc., to make sure it performed exactly as I had planned. ..... Here is a link to a battery discharge prevention device you might like. Best wishes!
 
The voltage will not change and neither will the current drawn by the dashcam. However, there is an issue with the inline switch as depicted. When it is on, power will back feed from the constant wire to the ignition/acc wire, which will usually cause devices on those circuits to turn on when they should be off.

To accomplish what is asked, I would power the dashcam through a small SPDT relay with the NC contact connected to ACC/IGN and the NO contact connected to BAT+. This way, the circuits cannot be cross connected and the relay is then controlled by a SPST switch connected to BAT+. When the switch is off, power flows from ACC as usual and when on, the relay engages and power flows from BAT+. Use a small 12V relay, not the typical 30 amp automotive relay. Those are way overkill for this application and wastes power. This however, can lead to a dead battery if the switch is accidentally left in the on position too long so using a BDP device would still be recommended.

KuoH

I think the voltage will be in parallel so it should stay at 12V but even if it's in series it will only be 24V which the hardwire kit can handle. I think the current would double if in parallel (remains the same in series) but that shouldn't matter either because of the hardwire kit. Or I could be talking total crap here? lol


View attachment 21660
 
Good point about the back feed, never thought of that. The SPDT relay sounds like the ideal component!

Speaking of battery protect devices, I'm not sure about the Multi Safer or the Vico-Power Plus but the Power Magic Pro seems to have a rather annoying feature whereby when it cuts off due to low voltage it won't switch back on automatically when you start the car, you have to manually switch the PMP off and back on. Maybe I've got a faulty device but if this is the way it works it sounds a little bit like a cheap design?
 
You could throw in a diode to control the direction of current and prevent the back feed.
 
I have the Multisafer and it automatically resumes from low voltage cutoff without any issues. No idea on the PMP, but I would think they'd mention it in the user guide if manual intervention is required.

KuoH

I'm not sure about the Multi Safer or the Vico-Power Plus but the Power Magic Pro seems to have a rather annoying feature whereby when it cuts off due to low voltage it won't switch back on automatically when you start the car, you have to manually switch the PMP off and back on.
 
You would need a power diode on each circuit, but that will also create an unnecessary voltage drop.

KuoH

You could throw in a diode to control the direction of current and prevent the back feed.
 
The Vico-Power PLUS does look pretty nice, but $75 is a bit too rich for my blood! :(

Ended up picking up a multisafer, hoping that will suit my needs...

One review I noticed on the multisafer said that the voltage cutoff basically doesn't have any "debounce". It will drop to a certain level, shut off the camera, but then the reduced draw from the camera being turned off results in higher voltage and the camera turns back on (repeat x times). Anyone have this experience?
 
Speaking of battery protect devices, I'm not sure about the Multi Safer or the Vico-Power Plus but the Power Magic Pro seems to have a rather annoying feature whereby when it cuts off due to low voltage it won't switch back on automatically when you start the car, you have to manually switch the PMP off and back on. Maybe I've got a faulty device but if this is the way it works it sounds a little bit like a cheap design?

You get what you pay for with the Vico-Power PLUS that's for sure. (Mercedes of hard wire kits)

Either one auto turns back on no problem as you can see in my demo video.

The Vico-Power PLUS does look pretty nice, but $75 is a bit too rich for my blood! :(

Ended up picking up a multisafer, hoping that will suit my needs...

One review I noticed on the multisafer said that the voltage cutoff basically doesn't have any "debounce". It will drop to a certain level, shut off the camera, but then the reduced draw from the camera being turned off results in higher voltage and the camera turns back on (repeat x times). Anyone have this experience?

I've shipped quite a few of these the past 2 years and don't recall any reports of that happening. Where did you read about it? Are you hooked up yet and experiencing it yourself?
 
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