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-   -   Battery drain experienced in my BMW 630d, and the reason behind it (https://www.team-bhp.com/forum/technical-stuff/258122-battery-drain-experienced-my-bmw-630d-reason-behind-2.html)

It is not advisable to use a device like cleaner or air pump in 12 v socket without engine running. Please revert to your old habit of keeping engine running :)

The effect with modern synthetic oil can be less but not necessarily. Modern engines have smaller tolerances than old ones. It is not so much about the lubrication properties but about the properties that make the oil stick to the cylinder wall when the engine is still cold.

It is the very reason that typical city cars (relative short trips) compared to long distance running cars always have a material difference in terms of wear and tear, synthetic oil or not.

Synthetic oils aren’t magic, you can’t really compare them to the non synthetic or semi synthetic oils. They were originally designed with different engines in mind. So when discussing wear you need to se that always in the context of a certain oil, a certain engine and a certain useable. Irrespective, short drives, prolonged idling does put additional wear and tear on an engine. The good news, it is very minor wear and it ususay doesn’t start showing up till 80-120k kilometers.

I am a bit surprised about VW advise. I haven’t seen that in Europe. One thing though, it will keep customers happy, because they don’t know what they are doing to their engines and it keeps VW happy as the additional wear won’t show until the vehicle is long out of warranty.

The one thing not mentioned is the fact that with idling, as I mentioned, you don’t warm up the engine or the exhaust system which means you are going to have condensation and all associated problems.
Could you show me a owners manual that instructs you to idle an injection engine at least once a week? If it needs that, there is a very fundamental design flaw!

Jeroen

Yes, there will be the usual problems associated with condensation but since the duration suggested is 25 minutes, I assume the wear and tear will be similar to short trips within the city that most owners take often.

And you’re right, it is a design flaw. The injectors supplied by Continental have this issue. Its present in Renault, Nissan & Ford diesel engines too.

Agree 100 percent to all points.

Here's what a manual from Fiat recommends - driving off slowly instead of idling after a cold start.



Well this is relevant only for lockdowns since there is no scope for driving. It is not SOP for cold starts per se. In fact during COVID lockdowns, many manufacturers gave similar suggestions but that again is ok to do very rarely and not as a practice.

Please read the context of the post. It is in response to someone who has requested a solution as he does not use his car for long periods (no scope for driving) and does not have an option to use a trickle charger. This practice is relevant not only for lockdowns but also in cases where similar situations arise.

Absolutely correct. After a certain period BMW Advance Car Eye 2.0 wont record videos during parking. I'm using it in my Bimmer for 3 years now.

Modern cars are tech laden and demand a lot of battery. You be surprised that the BMW battery won't last even 3 years.

Even cars like Skoda Octavia are facing this issue of battery drain if not used regularly.

Best would be to
1. Either drive car regularly. German car stay fit when driven regularly.
2. Install a BOSCH Trickle charger in your parking. Tell your society that you are getting a EV and need a power socket.

You can use Tire pump without starting car. You don't want to breathe diesel fumes while filling air. I use tire pump and car vacuum without starting car for past 5 years. As long as you use car regularly, no worries.

Well, you are lucky that battery is holding well. However even the instructions sent with the air pump mentions to start the engine first. I guess it is reasonable to say that we shouldn't put unnecessary load on the battery unless absolutely essential. Just sharing the instructions for reference.

It is quite different. At least on a short drive the engine and exhaust system will warm up. When you leave your engine idling, neither the engine or the exhaust system warms up. Especially on diesels!

Most cars/engine will reach operating temperature within 10-15 minutes of driving. And as pointed out DRIV3R and Fiat, that is taking into account just not Revving and loading up the engine.

Just an anorak fact. Don’t think your engine is at operating temperature because your temperature gauge is showing that. It measures cooling liquid temperature. Temperature of the oil always lags behind, the more oil your engine has, the longer it takes. The oil pressure gauge, if fitted, tends to be the best indication of the engine having reached operating temperature. But you need to get a bit of a feeling of the readings.

Jeroen

Well, this is the official recommendation from a manufacturer so lets get that out of the way.

As for the warranty getting over, VW’s warranty currently extends for 7 years or 150000 kms. There arent too many manufacturers who give warranties for 7 years. That is a long enough period to catch out a manufacturer.

The post is advice given to someone who has stated that he cannot drive his car and does not have the facility to connect a trickle charger.

So given the fact that he cannot drive the car and the fact that there could be injector failure issues, it is better we provide the best solution that is actually recommended by a manufacturer.

As a car owner, I would go with the official recommendation from a manufacturer rather than any other advice.

Can you please explain "auto switch off the car battery completely" feature ? what happens ? and will you be able to remote unlock the car whilst this feature is in force ?

Most Hyundais have this - if the battery is running lower than a threshold required to start the car again, the car shuts the battery off until next restart. They introduced/ advertised this as a feature too in the 2011 Verna, not getting the name they used...

When engine is turned off but accessories are still On (like radio, screen etc), it gives a message to warn user that battery may drain due to accessories. And after couple of minutes, it automatically switches off the accessories so as to prevent any drain issue. Of course, user can again start the accessories and the same cycle continues. So bottom line is that this mechanism prevents inadvertent battery drain.

Battery is still ON for any remote operation so it is business as usual.

Absolutley! You can check my posts over the last ten years and you will find I have said this a billion times. Glad to have found the one guy on the Internet that actually reads my posts, or has come to the same conclusion.

Don’t just trust the Internet over the manufacturer. Certainly I would not trust my posts, these days.

Just take it as additional information, which might be useful to some, if they choose to believe the Internet. Or just want to understand a bit more.

Between the hassle of a drained battery and some additional wear and tear on the engine I know what I would chose.

Still, I am an engineer at heart and I like to understand what idling does to an engine. Used to be involved in some research in this field with the TNO Delft and a Diesel engine manufacturer. We looked at the additional wear due to different cylinder wall temperatures and different operating regimes. It is posted somewhere on this forum, but I have no idea where. It’s been a while.

Jeroen

So it's nothing other than "only the always powered on Body Control Module computer (the guy in charge of remote lock/unlock , and the 'central server' of the network of computers within the car) will be on, rest everything will be off". That's the same as any regular entry level car with a factory fitted keyfob based lock/unlock. Just because Hyundai's have other 'fancy' features like ICE unit or air purifier or some other electrical device being on after engine has been shut off and key removed, doesn't mean it's a 'battery shut off" - the battery is still connected to the rest of the system, and the main computer (BCM) is still working (albeit in a low power state) , just that whetever other electronic switches that could have been left on by the driver , due to oversight, like headlamps, cabin lamps, ICE, charging devices, seat ventilation etc , will be forcibly switched off irrespective of the position/state of the button/switch that was left 'on' by someone , while the car was OFF-ed and locked.

Don't call it "auto switch off the car battery completely" - that is never done. Whatever possible human oversight loads have been left ON, they are forced OFF, that's all.

Well, looks like we’ve agreed to agree except for a minor change.

Let’s make this:

Between the hassle of a drained battery and some additional wear and tear on the engine I know what I would chose.

into this:

Between the hassle of a drained battery + failed injectors and some additional wear and tear on the engine I know what I would chose.

And now we’re good to go, thank you.