Hey, many years ago I hardwired a Blackvue dashcam into my Octavia, and used a switched live for the hardwire kit so it can turn off with the ignition or power itself after the ignition is off on a timer.

 

I'm currently not using the timer function to save some wear on the battery as the shortest option is 6hours of power after the car turns off, and I simply don't need 6 hours of footage of the rod by my house every day.

 

Consequentially I've started to notice that the fuse I've used for switched live must obviously also switch off with the stop/start function, as the camera dies every time I stop at lights (as it's not starting the 6 hour timer when stop/start kicks in).

 

So my question is, basically, is there such a thing as a fuse that is switched with key/ignition, but not with stop/start? (and bonus points if you have an Octavia III and know which fuse). I've checked a lot of dashcam threads but can't find a definitive answer on a fuse that is switched but keeps power with stop/start.

Piggyback the rear wiper circuit?

I want to say fuse 47 as I think I used , but I can’t fully remember.

 

Pretty certain I used 40 and 47, one being the lighter socket and the other the rear wiper.

Edited 19 January, 20224 yr by cheezemonkhai

Make of dashcam, as most of the better ones have both a motion timer and a voltage sensor to shut the dashcam down . My Nextbase has both. One motion sensor to start/stop the camera when the car is jolted and another voltage sensor which switches camera on when the voltage line drops, such as when a door is opened. Otherwise the dashcam ( when left alone in a stopped car) just shuts down.

On the recording side, most dashcam will record and wipe( i.e continue recording till memory card full and then over write). On the Fabia( possibly the same on Octavia ), my electrical side has what is known as circuits controlled by an X relay where such circuits are only on when ignition is on. In which case you could find one and use a "piggy back" fuse to provide power to that side. But with the consumption of a dashcam is it worth it? I'd suggest you get hold of a Haynes and look for any fuse controlled by an X relay if you want to go down that route. Or buy a decent dashcam with auto shut down/power up when volt rails vary.

13 hours ago, cheezemonkhai said:

Piggyback the rear wiper circuit?

I want to say fuse 47 as I think I used , but I can’t fully remember.

 

Pretty certain I used 40 and 47, one being the lighter socket and the other the rear wiper.

 

Almost certain I took the 12v socket as constant and the rear wiper as the switched too, but it's definitely shutting down the camera when stop/start kicks in? Will have to double check the fuse numbers when I can bring myself to try and remove that glovebox door again 😫

 

10 hours ago, VWD said:

Make of dashcam, as most of the better ones have both a motion timer and a voltage sensor to shut the dashcam down . My Nextbase has both. One motion sensor to start/stop the camera when the car is jolted and another voltage sensor which switches camera on when the voltage line drops, such as when a door is opened. Otherwise the dashcam ( when left alone in a stopped car) just shuts down.

On the recording side, most dashcam will record and wipe( i.e continue recording till memory card full and then over write). On the Fabia( possibly the same on Octavia ), my electrical side has what is known as circuits controlled by an X relay where such circuits are only on when ignition is on. In which case you could find one and use a "piggy back" fuse to provide power to that side. But with the consumption of a dashcam is it worth it? I'd suggest you get hold of a Haynes and look for any fuse controlled by an X relay if you want to go down that route. Or buy a decent dashcam with auto shut down/power up when volt rails vary.

 

I have a Blackvue DR900S-2CH, it'll switch to parking mode after not moving for a while and the PMP will shut it down at set voltage, but I'd still rather not have it recording nothing until my battery is low enough to tell it to stop. I have the PMP box accessible so I can switch it to timer mode if I do want to use parking mode at any point, but when I don't I'd rather it continues to record when start/stop kicks in (in case someone decides to drive into me when I'm stopped etc.) and for that I need to piggy back a fuse that is live only with ignition but also live when stop/start kills the engine (but I can't obviously drive around with the passenger door open and a multimeter stuffed in the fusebox stopping every so often to let start/stop kick in – well I could; but I imagined my life going in a different direction).

1 hour ago, Mort said:

Almost certain I took the 12v socket as constant and the rear wiper as the switched too, but it's definitely shutting down the camera when stop/start kicks in? Will have to double check the fuse numbers when I can bring myself to try and remove that glovebox door again 😫

Is the voltage drop when the engine restarts making the camera think the ignition has been turned off?

3 hours ago, PetrolDave said:

Is the voltage drop when the engine restarts making the camera think the ignition has been turned off?

 

Camera quits when the engine stops, but turn itself back on when it restarts, so can't see it being the restart causing an issue. Maybe the voltage drops with the stop?

Good call with a voltage drop though, could be the battery getting old and worn out (7y/o) – might look into that?

51 minutes ago, Mort said:

 

Camera quits when the engine stops, but turn itself back on when it restarts, so can't see it being the restart causing an issue. Maybe the voltage drops with the stop?

Good call with a voltage drop though, could be the battery getting old and worn out (7y/o) – might look into that?

I noticed when the stop/start kicked in that the voltage measured at the 12V socket would drop from 13.4V/12.6V (depending on the start of charge of the battery) to around 11.8V, maybe that's enough for the dashcam to turn off?

Checked and mine doesn’t stop when start stop kicks in off 47.

 

The wiper doesn’t stop either.

 

Are you only connecting to a switched live?

If so a small suitable smoothing capacitor in line might be enough to deal with voltage drop issues. Have to stay it doesn’t sound like that if it goes off.

5 hours ago, PetrolDave said:

I noticed when the stop/start kicked in that the voltage measured at the 12V socket would drop from 13.4V/12.6V (depending on the start of charge of the battery) to around 11.8V, maybe that's enough for the dashcam to turn off?

Nexbase tell me that there's two circuits. One is a shock sensor ,the other a voltage sensor. I can get in mine and opening door starts camera. Sit long enough and camera switches off. Turn on ignition and camera kicks back in. I don't thnk it's battery condition as I had the camera operating like that last year when battery struggled/failed to start car.

In my car, my camera keeps on recording for a few minutes after engine switched off , so I shouldn't think that it would behave any different on a stop /start model.

My camera is connected to the permanantly on ciggie socket, via a 12/5 v regulator, so I can only think that it's a small spike in the voltage rail that switches camera on. I suspect that you'd need a scope on he 5 v line to detect that , although any simple circuit that differentiates between the  5v line and any small differential should be capable of doing that.

On 20/01/2022 at 16:27, PetrolDave said:

I noticed when the stop/start kicked in that the voltage measured at the 12V socket would drop from 13.4V/12.6V (depending on the start of charge of the battery) to around 11.8V, maybe that's enough for the dashcam to turn off?

 

I think you were on to something here. The car started to have some issues turning over in the cold, so I plugged my charger in and got the battery up to 100%, and noticed just unlocking the car with the keyfob seemed to drop the voltage on the battery to under 11v when it was cold out.

 

Have swapped the battery out for a brand-new Bosch AGM and now the camera is behaving normally! So I think the stop/start must have been dropping the voltage to a point where the PMP was picking it up as low battery and putting the cam to sleep. Then, when restarting, it was seeing the ignition come on and booting back up pretending everything was fine.

 

tl;dr – battery was so toasted the camera was being weird, and I did wire it all in properly after all.

 

Cheers for the help all!

To be fair my battery just got replaced.

 

Even with fairly regular smart charger sessions it wasn’t turning a cold car over too well. 
Add the battery drain from the camera and it’s toast.

 

New battery seems to have no issues as long as it’s got a long-ish journey or a charge every 6-8 weeks 

My Nextbase shuts down after circa 5 minutes of no car movement. But we noticed this years ago with the Transits. Leave the sidelights on and battery dies in hours, whereas other heavier use items can leave battery live for hours.