Parking mode and unreliable "permanent" power in modern cars

[Tim Watts]

I just had a dashcam fitted today to a Mini (BMW, not original).

Ran into a problem where according to the chap (who is a specialist fitter), trying to get a clean 12V always on feed is nigh on impossible in BMWs and many modern cars.

He said that the car tends to put all ancillary circuits to sleep after a fairly short time (1-5 hours depending).

He also recommended against tapping to the battery as he said modern charging systems can throw the voltage very high (18V with higher spikes) instead of the failry reliable 14.4V old cars used to be.

So parking mode is a bit naff now as I seem to get maybe an hour before the "live" feed goes bye bye. The poor Power Magic Pro does not even get a chance to do its job as power seems to be cut early.

I'm going to be fitting the same make of dashcam (Blackvue DR650S-2CH) to a Hyundai Tucson next year and I was wondering if there was a solution to get parking mode to stay working for at least 24hours?


The obvious solution would be to inline a LiIon power pack. However, some people seem to be scared of these catching fire in the high summer temperatures inside a parked car.

Is that anything to really worry about or is there another clean solution?

<Longing for the days when fitting a radio meant 2 Scotchloks and an earth lug>

Cheers, Tim

 

[violreta3101]

I have been running thinkware 770 hardwired to 2016 civic and I have no problem power cutting off early. it draws so little power that it will stay on even on two straight days without car being used.

 

[Rajagra]

Surely if there's 18V at the battery, there's going to be 18V anywhere that 12V is supposed to be?
Or is there some monster regulator dropping it down to a more usable level? It would have to handle a lot of current if so.

I recently bought this rather good convertor, but haven't tested it yet. Doesn't really solve the problem you describe, but I expect a similar device is available to give a clean 12V or 13.8V from a battery voltage that varies a lot.

DC12V/24V/36V (8V~40V) Step-Down to DC 5V 30A 150W Waterproof Car Power Supply Module Voltage Converter Regulator
https://www.amazon.co.uk/gp/B01ENT1O62

 

[kamkar]

Thats a nice BEC there

I have a few similar for my RC needs, can step down from a 6 S lipo battery to anywhere between 5 volts and 9 i think it is. ( PC programmable )
And only 10 Amps, but thats fine for my RC needs as i use 7.2 Volts for my powerful steering servos, and thats about as much tourge it take to cut off a finger if you are not careful round the servo.

 

[Tim Watts]

I have been running thinkware 770 hardwired to 2016 civic and I have no problem power cutting off early. it draws so little power that it will stay on even on two straight days without car being used.

Yeah - a 2008 Mini cut off the power after about 30 minutes - just went out and checked.

This is from the internal fusebox. I might have a probe around and see if any other lines stay on longer.

The bloke did say it was a BMW problem that seems to be creeping into other makes. I have heard of BMW having weird electrics from other sources.

 

[Tim Watts]

Surely if there's 18V at the battery, there's going to be 18V anywhere that 12V is supposed to be?
Or is there some monster regulator dropping it down to a more usable level? It would have to handle a lot of current if so.

I recently bought this rather good convertor, but haven't tested it yet. Doesn't really solve the problem you describe, but I expect a similar device is available to give a clean 12V or 13.8V from a battery voltage that varies a lot.

DC12V/24V/36V (8V~40V) Step-Down to DC 5V 30A 150W Waterproof Car Power Supply Module Voltage Converter Regulator
https://www.amazon.co.uk/gp/B01ENT1O62

I assume there must be. It's news to me, but it was news to me when I found out my 2006 VW Touran's factory radio was wired into the CANBUS. Why? So it knew when the ignition was on FFS!!

I don't have a huge reason to disbelieve the bloke - he was well equipped and professional. Old cars cooked the battery at 14.4V max (alternator regulator). They could recover the battery quicker if the regulation was active rather than passive and the alternator voltage was allowed to peak higher, then be ramped back when the ECU decided.

It's all rather a pain in the bum - trying to get something as simple as permanent live power! I can live with the Mini as it is but would rather get the Hyundai right.

I wonder if a version of your converter is available with 12V output - I'll have a look.

 

[Tim Watts]

Just checked the fusebox. Tappings seems to coming from Hazard fuse (5A) and Radio (20A). I know the radio cuts off as soon as the ignition is switched off. Hazard I *would* have thought would have been on permanently but clearly not.

There's one nearby marked with a padlock (one of two marked with a padlock) - what's that? Central locking? The nearest is 5A, the other is 20A. 20A sounds more like door lock actuators. 5A - control unit? Wonder if that's worth a try.

 

[c4rc4m]

Surely someone sells a voltage regulator?

A direct connection to the battery via a voltage regulator should ensure a perfect 12 volts no matter what the battery actually does.

Also, on the subject of batteries, I'd have thought the biggest issue was actually capacity as many modern batteries are very marginal in size due to them needing small dimensions in very cramped engine bays.

 

[Tim Watts]

Have to be a bit careful with the voltage regulator - that it did not interfere with the Power Magic Pro's ability to spot falling battery voltage. ie we don't want a buck/boost regulator. What we need is something to chop the peaks off.

I'm going to put a probe on what looks like the central locking fuse controller (5A) (padlock symbol, there's another with the same symbol rated at 20A that I assume powers the door lock actuators). That surely has to stay on...

 

[SawMaster]

It wouldn't be hard to make a zener-controlled regulator tapped into the battery directly but that could also possibly affect the charging rate. The problem is that the charging system is no longer discrete- its controlled by the car's computer and finely engineered to allow them to minimize everything in the name of efficiency and lowest manufacturing costs instead of overall owner happiness. Better would be a well-regulated chip-controlled 5V P/S which I'm sure there are several made and sold though I don't know which are which as I don't use them. Run that direct to the battery and you're set. Except that the battery is minimal so you also need that powerbank because they didn't allow room for a bigger battery either. The upside is that most of the better cams have some over-voltage protection built in so perfection isn't required but it's always a good goal to seek. If you've got a new car under warranty your best bet is to have the dealer do the work so you don;t void the warranty.

Don't worry about good-quality LiIon powerbanks and summer heat in your car. Just be sure you don't place it where things get hotter than usual such as under a seat near the catalytic converter or in direct sunlight or by a heater vent. Avoid the cheap powerbanks- the cells they use are over-rated crap and are potentially unsafe even in the cool. There is not any way to make these a feed-through design, but that can be done with LiPo and other cell technology.

There is always a solution, but it's not always going to be easy or cheap!
Phil

 

[Tim Watts]

Don't worry about good-quality LiIon powerbanks and summer heat in your car. Just be sure you don't place it where things get hotter than usual such as under a seat near the catalytic converter or in direct sunlight or by a heater vent. Avoid the cheap powerbanks- the cells they use are over-rated crap and are potentially unsafe even in the cool. There is not any way to make these a feed-through design, but that can be done with LiPo and other cell technology.

There is always a solution, but it's not always going to be easy or cheap!
Phil

Aye... I notice that both Blackvue and Lukas make LiFePo4 packs which are generally regarded as "safe". Wow are they expensive, especially the Lukas which is 6Ah and still only gives an estimated runtime of 20 hours (Blackvue, my estimate based on capacity and power draw).

I'll have a chat with the Hyundai service dept and see if they fit, if they are able to source clean perm power.

 

[SawMaster]

You don't get what you don't pay for and safe high quality is never cheap- just always worth it LiIon is the touchiest battery technology commonly available but used correctly can be quite safe. The problem is that most folks don't know how to properly deal with it and there's a lot of disinformation out there regards how to handle it safely. LiPo in all it's variations is safer when things go wrong even though it lacks the energy density and capacity of LiIon. That makes it a far better choice for most people but still a good quality LiIon powerbank isn't something to be dismissed- just know how to use it safely and always do that

Phil

 

[Tim Watts]

The answer for the MINI at least is:

the ODB fuse (5A) fuse F37.

Seems quite permanent. Suggestion came from some old BWM forum posts.

I had to swap things around a bit as the bloke had assumed Radio fuse (full sized blade) = Perm (it's not, it shuts down 30 mins after parking up but wakes up for almost any reason, even opening an unlocked door.). So I used that for the ACC+ ignition feed. I'll look for a better one next week.

The ODB fuse is a mini-blade. Next tip: Wago lever connectors (new transparent type) are bloody excellent in cars...

So fingers crossed - dashcam has been running in parked mode for 5 hours. If it's still running tomorrow, success!

 

[Tim Watts]

And it is. Total success.

Now just to neaten it up, I'll see if I can locate a pure IGN/ACC fuse instead of the radio one with its weird power modes...