[Kosfactor]

Originally Posted by arjab

I wonder why, the luxury OEM's are not using Lithium-ion batteries in their expensive vehicles as energy storage solutions.

Yes lithium is better at keeping the accessories alive when the engine is off.

But car battery's purpose is to start the engine, Lithium isn't the best for that purpose without adding complex circuitry to protect the battery itself. The good old flooded battery needs nothing of this sort, works just fine as is.

[d3mon]

Originally Posted by GTO

• A contributor to my problem: I have the Varna rat repellent installed in my Bimmer & Superb, which takes up a mild amount of power, but is still a drain on the battery.

Assuming you don't park your car for significant periods of time outside of your regular parking at home, why don't you disconnect this device from your car, and instead just connect it to a 12V power adapter (costs <Rs 500) that goes into a wall socket?

It's important for the car to go to sleep fully. If the battery sensor sees a discharge, it will warn you that the car was unable to go to sleep due to parasitic discharges, and I think you posted similar error messages before. If the car goes to sleep fully, you should not see any discharge issues (especially with your new battery) even after 1 month of idling.

Removing the drain and the battery charger will also extend your battery life as batteries like to be stored around the 50% mark. Both 0% and 100% are not the best for long term storage (ever wondered why your mobile phones are around 50-60% charged from the factory?). In my car, the battery is rarely charged above 70-75% State-of-Charge, and this smart charging is the reason why these batteries last so long on BMWs. Also, charging to a slightly lower level leaves the remaining capacity to be charged via the Efficient Dynamics branded 'KERS' when you are coasting without consuming fuel.

[Samba]

Even my Duster AWD behaved odd with a weak battery.

The early sign was, it was taking longer to crank. I ignored it thinking the car sat idle for a month, so if the car is taken out for a couple of days, it should get sorted.
But while on the move there was a knocking, the injector lights came up once, the cruise control got off automatically. Renault confirmed, a weak battery can damage its electronics and the injectors may also get affected.

The very next day, the car refused to start. Changed the battery. All were fine.
So now if the car is idle for a week, I make sure I start it atleast once or take it for a small spin.

[androdev]

Originally Posted by d3mon

Removing the drain and the battery charger will also extend your battery life as batteries like to be stored around the 50% mark. Both 0% and 100% are not the best for long term storage (ever wondered why your mobile phones are around 50-60% charged from the factory?). In my car, the battery is rarely charged above 70-75% State-of-Charge, and this smart charging is the reason why these batteries last so long on BMWs. Also, charging to a slightly lower level leaves the remaining capacity to be charged via the Efficient Dynamics branded 'KERS' when you are coasting without consuming fuel.

50% state of charge you mention applies to Li-Ion/Nickel etc batteries. Lead acid batteries (AGM, flooded) last longer if maintained at 100% state of charge. It is perfectly safe and recommended to keep lead acid batteries charged to 100% irrespective of regeneration feature. Most authorised showrooms keep their display cars connected to a maintenance charger that keep the batteries 100% charged all the time. Some performance cars come with Li-Ion batteries and they have to use a Li-Ion specific battery charger as regular battery charger will damage them.

[mikem]

Quite surprised as my W212 has a battery voltage of 11.6 volts parked in the mornings, even after a week of no use; and no issues for me. Charging volts are 13.6-14.1. It’s been stagnant at this voltage (11.6v) for over a year.

Is it time to get a trickle charger or get the battery replaced?

[Pulse500]

Originally Posted by arjab

I wonder why, the luxury OEM's are not using Lithium-ion batteries in their expensive vehicles as energy storage solutions.
Lithium-ion batteries perform particularly well where constant current draw is required to keep systems and sub systems ticking.

Its a great suggestion to have dual batteries. One ultra-long-life low capacity lithium battery pack for the core electronics to continue functioning when vehicle is unused for a few days. Modern electronics are much more efficient, work at lower voltages and draw lesser current.

And the regular Lead-Acid battery for the high-current vehicle starting, lighting, entertainment and loud alarms if any.

I will send some pictures of my car separately which provides trickle charge to battery using solar cells.

[UP!!!!]

Surprisingly my BMW 3 Series (~3.5 year old) just gave me a low battery warning when I started it after 2 months of idling. During these 2 months, it was cranked by my neighbour only twice for 5 minutes each time in the gap of 20 days.

I was very happy at the end and did not have much expectations from 3.5 year old battery.

[sramanat]

That's just poor engineering, bordering on evil. You don't tell the user "ABS will work partially". You tell the user "power source for ABS sensors is weak". My team develops products which have a tall list of fancy diagnostics in place. A simple "Contact Service" will result in actual service calls and our program gets billed by the service arm of the company. And we can expect nice words from everyone in our program review calls. . So we go through great rigor before showing the user an error message. For these luxury car guys any random light that goes off in the instrument cluster (the "contact service" equivalent) is another way to milk money from the customer.

[Pam81]

They must throw actual issue of low voltage rather than pushing to go for service. When developers write the requirements, they do take into account of the voltage range from battery as one of the check point for diagnosis and error messages of the system. The infotainment and error message configurations gets tweaked in different versions. I suspect the display unit and ICE must have a different software configuration for India with a different part number etc. Cheap!

Few years ago, I was chatting with a service center manager who used to work with Audi & Jag service and he was constantly blaming the incompetence of the Foreign brands' adaptation for Indian conditions and notion of milking money with least changes. I heard him saying that they were blaming the dusty conditions in India due to which electronic sensor failures were high. That's awful, you can't blame environment for your failures!

Cheaper costing 2 wheelers throw up actual error messages than simply hiding the info and tricking the user to blindly go for service!

[R2D2]

Originally Posted by mikem

Quite surprised as my W212 has a battery voltage of 11.6 volts parked in the mornings, even after a week of no use; and no issues for me. Charging volts are 13.6-14.1. It’s been stagnant at this voltage (11.6v) for over a year. Is it time to get a trickle charger or get the battery replaced?

Well, 11.6 is really low. Normally shows a faulty battery. However, with a luxury Euro vehicle it's always best to buy a quality battery charger as pre-emptive maintenance to avoid the vehicle systems throwing a fit and leaving you inconvenienced or stranded. Do get the battery tested using a battery health analyzer which any MB dealer will have. This outputs a report that shows detected resistance, approx. CCA, capacity and whether you need to replace the battery or not.

Get either a Bosch C7 (real VFM) or a CTEK MXS 5.0 or MXS 7.0 (expensive). CTEK is the most recommended brand of charger by lux car Companies. You won't go wrong with any type of battery your car may have which incidentally should be an AGM sealed unit.

[Pacific]

All modern cars tend to draw small amounts of power from the battery. For us, this problem exacerbated during Covid as the cars were left disused for extended period of time. Last February, I purchased NOCO Genius5 and a multimeter to monitor the state of charge of batteries for both our cars. So far, this charger has worked flawlessly and IMHO, its a small investment for maintaining a healthy battery.

https://www.amazon.com/NOCO-GENIUS5-...EF6YCWRPBNSGDG

Image source - Amazon

[TheDonGogoi]

Hello,
I am a new member to the TeamBHP community, glad to know your problems with the car have been sorted out. I would like to know about how we can check the system voltage on a BMW car mine is 3 series (G20) and it doesn’t get used very often, in fact only around 4K kms or so in the almost 2 years of ownership. I would also like to know if checking or opening the cars system voltage menu would cause any harm from the OEM side in terms of warranty or service.

[frewper]

I think we should not be blaming German cars because this can happen to any car that has a lot of sensors.

In essence its the sensors that doesnt like low voltages and in turn the car behaves erratically.

A sensor typically works by taking an input voltage, and given out a specific output voltage. The range of this output voltage will typically dictate the state of the sensor.
Ex. HIGH, LOW, ETC.

Now the problem is ze Germans got a lot of sensors on them,

Now when the input voltage goes erratic, all the sensors starts giving out incorrect values and the system things everything has failed.

Also another alternative to hooking up your car to battery charger, (In case you dont have a power point near by) is that you can actually disconnect the positive battery terminal and the battery will hold power for two months easily. Only drawback is that the security system wont be working. But if you have secure parking, you should not worry

[ynot]

Last year, with Covid, the missus was only driving her A3 short distances. One day when she went to start her car the dash lit up like a Christmas tree with a bunch of error codes. Luckily, our neighbour lent us his charger to charge the battery. Even after a good 16 hour charge, the car yet refused to start. Long story short, a new battery and it started to behave.
I started working from home 2 months back, reducing my daily 70km (work) round trip to 4kms (dropping the kid to daycare). After the first week, got a warning on the Mazda's dashboard and the stop-start wouldn't work. After 3 weeks of driving without any real issue I got the battery replaced. Atleast unlike the Audi, I only lost the provision of the Stop-start and was not stranded on the road.

I guess the Germans have a different way of handling low battery voltage as compared to the Japs, and our cars are about the same age, 6 years old.

[Maverick5490]

Originally Posted by Turbanator

Can this be limited only to Diesel German cars?

These AGM batteries with permitted current drain can last 4-5 years with good usage, in GTO's case it is the Rat repellent that is violating the standby current.

Originally Posted by arjab

I wonder why, the luxury OEM's are not using Lithium-ion batteries in their expensive vehicles as energy storage solutions.

BMW M cars come standard with lithium-ion batteries, an AGM battery costs around 45k whereas the lithium-ion costs 1.2 lacs.

Originally Posted by d3mon

Assuming you don't park your car for significant periods of time outside of your regular parking at home, why don't you disconnect this device from your car, and instead just connect it to a 12V power adapter (costs <Rs 500) that goes into a wall socket?

@GTO this is a good idea to consider since you face Rat menace only when parked at your residence.