Dashcams in Vehicle with Stop/Start Function

[c4rc4m]

that will be good if ever you're in a serious accident and they pull the data from the computer that says you were driving with the hood open

Would be funny, but a simple inspection would show the wire had come loose. That said, there are better ways of defeating stop / start such as the off button on most cars, albeit you usually have to press it for every journey.

As an aside, not sure of safety requirements in the Far East but the EU has required all vehicles to have a 2nd safety catch on the bonnet from way back into at least the early 70's. I can't ever remember seeing a car without one, although at some point they wouldn't have been fitted.

 

[Rhody401]

I think the power will remain constant/stable and that this is a non issue. Think about how it would be for things like a dvd player, wipers stopping, or even the radio rebooting, if this was the case. The battery should have plenty of power to keep things on while this happens.

 

[DT MI]

I think the power will remain constant/stable and that this is a non issue. Think about how it would be for things like a dvd player, wipers stopping, or even the radio rebooting, if this was the case. The battery should have plenty of power to keep things on while this happens.

That's the problem - power does not remain constant for all circuits (which I'm sure varies by vehicle). Toyota documents this as I pointed out in post #7 of this thread ( https://dashcamtalk.com/forum/threa...e-with-stop-start-function.29616/#post-346009 ). For that vehicle specifically, and I'm sure many others, it would necessitate hard-wiring and finding a circuit that does not lose power during the restart.

 

[Rhody401]

I doubt it is by design, but perhaps due to a car battery near the end of its life. (too weak to do it all)

 

[Dashmellow]

just simpy disconnect wire connector from switch. I did it very soon and i have been driving like that for 3 years now and everything works well, car computer thinks that hood is open and start stop system never activate.

that will be good if ever you're in a serious accident and they pull the data from the computer that says you were driving with the hood open

Well, he would hopefully have his dash cam footage to prove that the hood was not open. That's why we have dash cams, right?

 

[DT MI]

I doubt it is by design, but perhaps due to a car battery near the end of its life. (too weak to do it all)

More likely is a matter of 'lack of design' to insure uninterrupted use of accessory circuits during the restart. Were it an issue with battery condition I doubt it would be addressed in the owner's manual as being normal.

 

[2000rpm]

That's the problem - power does not remain constant for all circuits (which I'm sure varies by vehicle). Toyota documents this as I pointed out in post #7 of this thread ( https://dashcamtalk.com/forum/threa...e-with-stop-start-function.29616/#post-346009 ). For that vehicle specifically, and I'm sure many others, it would necessitate hard-wiring and finding a circuit that does not lose power during the restart.

Some cams have firmware and hardware which will tolerate the loss of 12v supply during cranking.
My household has (and had in the past) a handful of cars where 12v supply goes off during cranking.
Of the capacitor cams I've tried, Street Guardian, Panorama and JooVuu cams haven't given me any trouble.
Of the battery cams I've tried, Transcend DP100 hasn't given any trouble, nor Mobius set for 10s power-off-disconnect. In fact, due to being unable to use Capacitor Mobius in my car I use them with battery and set for 60s power-off-disconnect and the cam continues recording for a minute after I leave the car, or potentially a minute after an accident has cut power to my vehicle. A lot of interesting things could happen in that first minute after stopping - admission of guilt from another driver who walks over, or capturing a mugger's face as they try to snatch something from me as I leave my vehicle.

My main car has a JooVuu (capacitor, 3s p-o-d) looking straight ahead and another looking out the rear window.
It also has two angled Mobius (battery, 60s p-o-d) cams in the front which between them cover the whole 180 frontal arc, plus another looking out the rear window.
The cams are all small, so they're barely noticeable, especially due to being able to find a wide range of mounts that they can be attached to.

 

[DT MI]

Some cams have firmware and hardware which will tolerate the loss of 12v supply during cranking.
My household has (and had in the past) a handful of cars where 12v supply goes off during cranking.
Of the capacitor cams I've tried, Street Guardian, Panorama and JooVuu cams haven't given me any trouble....

My concern is a total power loss during the restart and the capacitors not having sufficient capacity to maintain operation for longer than is necessary to effect a controlled shut down of the camera.

My current vehicle has RAP (Retained Accessory Power) that keeps accessory circuits powered for up to 10 minutes after the ignition is turned off (or a door is opened). This works fine and the radio, for example, continues to play uninterrupted during that period.

Unfortunately the accessory power outlets (cigarette lighter) don't follow the same rule and shut down completely when transitioning to RAP mode (see this: https://dashcamtalk.com/forum/threads/sg9665gc-files.10648/page-2#post-136153 ). It's this short term power down/power up cycle that I feel will adversely affect some cameras, specifically capacitor based cams - and specifically my SG9665GC. (Read this entire thread for background on how I came to find this out if you're interested: https://dashcamtalk.com/forum/threads/sg9665gc-files.10648/ )

From the way the Toyota Highlander manual I quoted earlier is written it sounds like the same thing will happen during the stop/start restart as what happens during the RAP transition. If that's true (accessory outlets lose power but accessory circuits, like radio, don't) then hard wiring will be the only option - and I'm personally not looking forward to figuring out how to hard wire 4 cameras, in a new vehicle, without affecting the warranty. It's either that or going back to battery based cameras that will be less affected.

Edit: Researching this a bit further I found this in the Honda Pilot Owner's Manual:

Doing a bit more research on this issue I found the following from the 2017 Honda Pilot owner's manual:

• If you are using an electronic device during Auto
Idle-stop, the device may temporarily be turned off
when the engine restarts.

So it looks like this is not something related to just Toyota.

 

[2000rpm]

My concern is a total power loss during the restart and the capacitors not having sufficient capacity to maintain operation for longer than is necessary to effect a controlled shut down of the camera.

For how long does your 12v socket lose power?
My current car and my previous car briefly cut the 12v supply when starting the engine.
JooVuu with caps will tolerate three seconds without power because it's in the firmware and there's an option for 3s p-o-d in the app. If power resumes after two seconds it'll be as if nothing happened and the cam will continue writing the file that was in progress before the power interruption. If power doesn't resume after three seconds the cam shuts down.

I also have no problem with SGZC12RC and Panorama II S. Their firmware seems to be set in such a way that shutdown takes a fraction of a second and in every off-on-off test I've done the cam always re-boots if power returns. However, it can take 30s for caps to fully recharge so interruptions to power within 30s of the cam rebooting might cause corrupted files with the second and subsequent interruption.

I can't comment on the SG9665GC because its form factor isn't suitable for my car. I had an A118C but gave it away and didn't thoroughly test its tolerance of power interruptions. I also haven't tested the tolerance of my CF-100 because it's in our one car with an always-live 12v supply so there aren't any disruptions to its power supply.

 

[DT MI]

For how long does your 12v socket lose power?
.....
JooVuu with caps will tolerate three seconds without power because it's in the firmware and there's an option for 3s p-o-d in the app. If power resumes after two seconds it'll be as if nothing happened and the cam will continue writing the file that was in progress before the power interruption. If power doesn't resume after three seconds the cam shuts down....

Nearly 2 seconds between the power drop and return to 5V.

The issue could be resolved in F/W but only if the capacitor is large enough to support normal operation for the desired period.

 

[c4rc4m]

Maybe an uninterruptable power supply / battery back up such as used for parking mode cams?

 

[Dashmellow]

Nearly 2 seconds between the power drop and return to 5V.

The issue could be resolved in F/W but only if the capacitor is large enough to support normal operation for the desired period.

You can certainly purchase large powerful super-capacitors.

A company called Green Tech specializes in them along with super-capacitor modules that are intended for use as uninterruptible power supplies, among other applications.

http://www.greentechee.com/16V-500F-super-capacitor-module-large-power-extremely-low-ESR_p42.html


http://www.greentechee.com/16V-500F-super-capacitor-module-large-power-extremely-low-ESR_p42.html

 

[DT MI]

OK, I've been doing a bit more 'research' on this subject so time to breath a bit more life into this thread.

Seems most of the disclaimers/issues about accessory power loss during the idle stop/start cycles have to do with voltage drop during engine cranking versus anything having to do with system design (or lack thereof). It seems that Toyota has partially addressed the issue by shortening the engine 'crank time' during restart but that's not a real solution, just a matter of mitigating the impact.

This got me to thinking (again, dangerous I know) about @Dashmellow 's comment above about capacitors. Would it be feasible to make an 'in-line' capacitor with either 12V or 5V inputs/outputs that could be used to 'absorb' the voltage drop before it affects the dashcam? (Or better yet, at least in the case of 5V cameras, incorporate this functionality into the 12V/5V converter.) How large, physically, would such a device have to be to handle a 2-3 second voltage drop?

 

[Dashmellow]

This got me to thinking (again, dangerous I know) about @Dashmellow 's comment above about capacitors. Would it be feasible to make an 'in-line' capacitor with either 12V or 5V inputs/outputs that could be used to 'absorb' the voltage drop before it affects the dashcam? (Or better yet, at least in the case of 5V cameras, incorporate this functionality into the 12V/5V converter.) How large, physically, would such a device have to be to handle a 2-3 second voltage drop?

I made exactly this suggestion about an "in-line" capacitor quite some time ago in another thread about the same issue that members were reporting in "certain" vehicles with the Mobius camera running on early firmware. The idea was that the ignition would pre-charge the in-line capacitor enough to keep the camera up and running throughout the entire ignition process. Another member at the time who is far more knowledgeable about these things than I am said that would indeed be a good idea. I don't know what capacity value would be needed but I don't think it would need to be all that much to power the camera for a few seconds until the voltage is constant. I would imagine this would require some simple ancillary charging circuitry to work properly.

Assuming that such a circuit would continuously charge the in-line capacitor it could work for the start stop-issue keeping the camera running whenever it is called for.

 

[Bungus]

OK, I've been doing a bit more 'research' on this subject so time to breath a bit more life into this thread.

Seems most of the disclaimers/issues about accessory power loss during the idle stop/start cycles have to do with voltage drop during engine cranking versus anything having to do with system design (or lack thereof). It seems that Toyota has partially addressed the issue by shortening the engine 'crank time' during restart but that's not a real solution, just a matter of mitigating the impact.

This got me to thinking (again, dangerous I know) about @Dashmellow 's comment above about capacitors. Would it be feasible to make an 'in-line' capacitor with either 12V or 5V inputs/outputs that could be used to 'absorb' the voltage drop before it affects the dashcam? (Or better yet, at least in the case of 5V cameras, incorporate this functionality into the 12V/5V converter.) How large, physically, would such a device have to be to handle a 2-3 second voltage drop?

My RAV4 Hybrid's starter use the hi-voltage supply. Not 12 volts. Not sure about yours.

 

[DT MI]

My RAV4 Hybrid's starter use the hi-voltage supply. Not 12 volts. Not sure about yours.

Actually, my current vehicles don't have S/S but their replacements will and I'm just 'getting ready'.

I have learned that hybrids (or at least those that I've considered so far) are completely different animals and accessory power interruption is not an issue.

 

[SawMaster]

An in-line cap pair should work if you use blocking diodes before and after the caps to ensure uni-directional current flow; those would need to be sized for the caps being used. It might be possible to only block the feed side of the caps, I'm not sure there would be any tendency for reverse current flow downstream to the cam. Cap size would need to be large enough to cover the expected under-power interval. Someone with a better junk-box than I've got should try this- the only supercaps I have are an extra unit for Mobius which would be too small.

Phil

 

[Dashmellow]

An in-line cap pair should work if you use blocking diodes before and after the caps to ensure uni-directional current flow; those would need to be sized for the caps being used. It might be possible to only block the feed side of the caps, I'm not sure there would be any tendency for reverse current flow downstream to the cam. Cap size would need to be large enough to cover the expected under-power interval. Someone with a better junk-box than I've got should try this- the only supercaps I have are an extra unit for Mobius which would be too small.

Phil

I have some caps I could try this with but it would have to go on the end of the "to-do" list which has been getting longer by the day around here. Might be a good "deep winter" project to fiddle with.

 

[Bungus]

Actually, my current vehicles don't have S/S but their replacements will and I'm just 'getting ready'.

I have learned that hybrids (or at least those that I've considered so far) are completely different animals and accessory power interruption is not an issue.

My mistake. Thought you're getting a Hybrid with Stop/Start.

 

[Nigel]

I have some caps I could try this with but it would have to go on the end of the "to-do" list which has been getting longer by the day around here. Might be a good "deep winter" project to fiddle with.

It's not going to be possible to fit it into the normal cigar lighter adaptor, too big.

If you have the space then you have a choice of doing it on the 5v or the 12v.

If you do it on the 5v then you can use a super capacitor at reasonable expense, however you need to check that the voltage is not above the 2.7v x 2 limit for 2 supercaps which some car adaptors do exceed at times and you still have the issue that as soon as the power goes the voltage will start to drop and the camera will probably shut down when you have only used 1/4 of the power in the supercaps, thus you need big supercaps.

If you do it on the 12v supply then the voltage drop over time is not a problem because the voltage regulator in the adaptor will continue to output 5v until the capacitor is nearly empty. Your problem then is that you can't use a cheap supercap since it needs 6 in series to cope with the 14.6v car voltage (maximum with alternator running). Probably best to use a conventional 16v or 24v capacitor, but then you need quite a big one to keep the camera going for any time. Plus you need to add a diode to prevent the power going back to drive the starter motor. Fairly easy to do, just a bit big and too expensive to make into a sellable product.

Still not convinced that it is needed with a decent AGM battery as found in cars with stop start, especially when you have a modern 1L turbo engine that takes little energy to start.