BMW MY08 X5 Battery Problem
 

I replaced the original battery on my X5 back in 11/2014 and it was working fine until 2 months ago when things start to act up. I would go to start the car and it wouldn't start. So then I tried a couple of time afterward and it started. This happened 4 or 5 more times the past 2 months. So I've been doing alot of my own investigation. I've confirmed that there are no parasitic draw when in sleep mode (10mA after 30 minutes). I've confirmed the alternator is good as it's constantly putting out 13-14.5V at the battery as I'm driving or when car is started. I've taken the batttery to Advaced Auto Parts and they've told me that this battery is good based on their test.

So I attached a voltmeter on the battery last night and the reading was 12.5V. This morning, before I started the car I checked the battery and it was readying 12.3V which should still be good. Then I unlocked the car door with the key and after 30 seconds, the voltmeter would ready 9.2V. I was shocked to say the least. So I started her up and she started up and then alternator kicked in. When I turned her off this time, the voltmeter reading is back to 12.5V and it stayed that way. So I repeat the entire process of locking the door, waited, then unlocked the door and the same thing happend. Voltmeter reading went from 12.4V to 9.1V within 30 seconds to minute after unlocking the car. Is this a sympton of a bad battery? I'm clueless at this point what the issue would be and how a battery can go from 12.4V to 9.2V within a minute. Please help.

Thank you.

Kiet

I think you should also consider the alternator.

The voltage of the battery means nothing if there are no Amps doing the work.

I guess this is where I'm confused since once I start the car and let it run for one minute, the battery would read 12.50V after turning the car off and letting it sit again. Does it make sense after letting the car run for 1 minute that the battery will jump from 9.2V to 12.5V again. It's odd or maybe I just don't understand enough about batteries. Plus - how am I able to start the car with just 9.2V reading on the voltmeter? That is also odd in itself.

[/QUOTE] Testing it once and seeing no parasitic drain isn't conclusive. Some
of them are sporadic and you might not have caught it. You could
try measuring the battery at night, then leaving it disconnected
over night, see what it reads then.[/QUOTE]

I have done the parasitic test several times already and it shows 10mA everytime after the X5 is in sleep mode. I have also done the measuring battery overnight with it disconnected. It was from 12.75V to 12.68V the next morning with it disconnected. I've done several alternator test and all indication is that my alternator is fine. We drive this car all the time so it should be sufficiently charged at all times. I guess I could try to buy a new battery just to rule out the battery issue but I hate to waste over $200 and it not being the problem. The battery is only 6 months old.

Thank you all for all the advice so far.

Have you looked that parasitic draw overnight??? Like logging it for 12 hours?

These cars will shut down, draw seems fine...but then a module wakes up the whole system and it then draws the battery down. Can happen every hour. Pretty soon, after a year of being deeply discharged every night, the battery is toast.

Yes - I am testing it right at the battery in the trunk. I've checked for tightness and for corrosion and both are good. I'm pretty confident my meter is correct. When I check my other cars, it read 12.7V.

AAP have a machine that they used to connect to the battery and it will print out a report stating whether the battery is good or bad. According to that machine, it's good. I think they also did a load test as well.

I have also noticed that when I first start the car, the voltage reading would drop from 12V to 11.5V for about 30 seconds or so. The car would hesitate during this time until the alternator kicks on and the voltage ready goes up to 14.5V on idle. Is it normal for the alternator to take 30 seconds or so to turn on after engine is started?

Kiet

I do have the DCAN and Edibas software but I only know the basic usage of it. I can look at IBS information but it really doesn't tell me any history. I've looked and looked and can't find any good information regarding that.

E70+ need to have a batteries characteristics defined to the x5 otherwise it doesn't know exactly how to charge the given battery. The battery needs to be a ago type.that can better handle the discharge.recharge cycles the x5 design will do to it. The x5 only.charges using the alternator when coasting. So if you do a.lot.of.short runs on level land you can discharge.the battery... the car will.get crazy as.the voltage of battery runs low. A fully charged battery with the car on but not.running should be over 13.volts not under. So I advise.you recharge.the battery.with a ago approved charger and.see how.the car.acts. fyi the charging.design is.crazy.bad .... do a search on Google using n63 hearing batteries and read ... n62 design is.the same just doesn't have a electrical discharge.of.fans.cool I g.turbo.

Search with n63 eating batteries a road and.track article describes the design problem. Fyi I ordered a 12 dollar digital volt meter with two sub phone charge ports so I can monitor.the battery charge via.small.voltage.level variance Learning small voltage levels like maybe 13.4 battery fully.charged.and.maybe 13.0 battery half.charged.Will help us manage.the battery ..... sad we must.do.this. I will use.agm capable battery tender.charger to charge.the battery.if.I.discover.we.need.to rather than see.the battery.harmed by significant.discharge or.risk having.the battery not.having the charge.to operate.the car. I will make an plug.in adapter.to.front.of bmw.grill.to.plug.car.into.charger.if.I.discover.t hat.is sometimes.needed. yep.it.is nuts

That article has a few valid points but the issue is not as grave as they make it sound. 4.5 years on the original battery here. Many have experienced the same. When you start to get the high discharge alert, a new battery is in your future. A lot of short trips will cause the battery to fail sooner as it never gets fully charged. So 5 to 10 miles trips will be an issue. Nothing says you can't do short trips but you will either need to take a longer trip to charge the battery up or get a battery charger and put it on the charger a few times a week.

Yes a lot of short and.level trips setup for a deeply discharged battery and recharging from deeply discharged kills batteries. My wife.works from home.and.when she uses.it.Will.drive.a.few.miles.to.the.store.or.gym on level.ground. I have.a.330I and.drive.just.like 2 miles.to.work. so maybe 6000 miles on each car.for.a year with some.signify can't.distance.traveled.on.some.weekend.in one.of.the cars. So I just.got.the x5 and now.realize my low mileage use does.fit.the charging.system .... hence.my plan.to manage.the battery and.plug.in.the car. It.is a.stupid.design that.Will not.keep.the battery at.75percent at least. I am a firmware software engineer.with many years.of.experience .... hey bmw it.isn't.serving your.customers.well!

BMW is not alone is battery issues though, other manufacturers have issues as well. They are putting more and more electronics in but the charging system hasn't really changed. This causes issues. Did BMW make some poor decisions that other companies didn't make? Sure, but they also made some decisions that are better than what others have done.

There was talk of 42-volt electrical systems in the 90's. Those obviously never materialized. in 2011 the Germans manufacturers agreed upon a 48 volt system.

A few things BMW should have done for N63 based vehicles. When you pushed the park button, the alternator should have engaged (unless that battery was already at 100%.) While a second or three would not do much for the battery system, a bit of power would have gone into it. Next, they should have activated the cooling fans to help draw air through the radiator and expel hot air out from the engine bay compartment. This should allow the cooling system that runs after the engine is turned off to run less; how much is debatable but every bit helps.

To help cool the turbos on the Ford Ecoboost 3.5l V6; after the engine is off, cooler coolant is automatically circulated through the turbo because of their setup. BMW is using electrical pumps to do it. I'm sure the BMW method is more effective at removing heat, but it is at the expense of the electrical system.

I went ahead and bought another brand new battery today from BMW. Hopefully - the Autocraft battery was the culprit even though AAP technician told me battery was good.

your battery can't deliver the electrons -- no charge held?
 

You need a means of measuring the current (amps) draw when the voltage takes the plunge! Guessing ...
Your battery has NO stored-reserve to give so when you unlock the car ... the car systems power up and there isn't enough "juice to give"? 9/2v and everybody would be flaky! So you battery has no power reserve. Either the battery isn't charged or it can't hold a charge anymore?

What does the autoparts store think of the battery now? Do they think it is fully charged, can they tell? My guess is another fully charged battery and everything works great.

My guess is you do not drive many miles and the miles you drive are flat ... so little coasting to charge the battery.

Anyway another new charged battery and it will be fine for about as long. Could be the battery wasn't introduced-setup correctly to the X5? Could be a bad battery from the beginning but I doubt that.

Answer these questions please!
 

So now it will work fine for some months, the question is how will it be in 6 months?

Answer these questions ...

1. How many miles a week do you drive?
2. Are a lot of these miles at night?
3. Are the roads flat or nearly so where you live.

Reasoning for questions ...

I repeat the car ONLY recharges the battery when coasting and that happens only lot when going down hills.
Drivng a car at night means you have the lights on ... lights use more power!
If you drive few miles from home to wherever you use a lot of juice powering up and starting the car and when you don't drive far ... enough coast-charging doesn't occur.

Note the voltage reading on the battery when you first install a fully charged battery (write it down) ... not how it drops a little lower every week?

That is not correct in that the car only charges when coasting. The system charges the battery but will decouple the alternator from the engine under acceleration or when the battery reaches 80%. If you are braking, coasting, etc. if the battery is not at 100%, it will then couple the alternator back into play.

Watch the video:
BMW EfficientDynamics : Brake Energy Regeneration

The bigger issue is that the battery is never getting fully charged. Short trips do not replace the amount of energy consumed by starting the vehicle. If you do a lot of short trips, BMW recommends that you either buy a battery charger or go for a long drive. If the alternator only worked when braking or coasting, then why would a long drive help? You could drive until you ran out of fuel and no power would have been put into the battery. The N63 issue is a little different. You have that the battery will probably only see 80% charge, but when you turn the engine off you still have the cooling system operating. Keep in mind that many manufacturers use a mechanically driven water pump; BMW is using electric. So how much energy is being used for the pump to run and how long is it running after the vehicle is off? You also have that after you open a door and get out, if you don't lock the vehicle, the radio is still operating. Once again, consuming power. Pathway lighting is also running. Then you have the normal items that are always drawing power; comfort access/remote receiver, etc. So even if the alternator only charges to 80%, you need to drive far enough to let the alternator charge the battery to 80%. If you only get it to say 75% on day 1, then 70% on day 2, then 65% on day three. You are not driving far enough to actually help. If you make a 5 mile trip and there were four stops, how could you ever actually charge the battery up? Especially if the cooling system is running the entire time.

Ford uses a different system so that a turbo timer isn't required. BMW doesn't use the same system as Ford but once again, they didn't want to use a turbo timer. Ford has battery issues of its own, it just may not to be the degree of BMW. Ford also isn't using electric water pumps, etc. A larger alternator might be beneficial for BMW to use. This way shorter trips when the battery is below 80% it can provide more power to charge the battery.

FYI ... I believe my newer BMW battery will become discharge with our lite use of the X5 and I believe we can ruin a battery sooner this way. My plan .... I have showing up tomorrow a cigarette lighter "voltmeter" etc. called A "Jebsen 4in1 car charger" for $11.99 via Amazon. I will monitor the batter voltage with this! I will then fully charge the battery using a 021-0123 I already have for my boat.
And then I watch the voltage at rest. I suspect the x5 voltage will drop over weeks and as needed I will charge the battery weekly or bi-weekly? To make this easier I may need to install a plug in my x5 grill to go to directly to the battery "jump spot". At any rate ... I will not see the battery harmed or have the car ... strand me or my wife. I won't even let the X5 confuse me with failing systems because they aren't working right because of a low battery ... go figure.
I am a engineer this isn't rocket science but it isn't it just it works either! Shame on BMW for making such a stupid flawed design here!

I recommend BatteryUniversity.com by Cadex Electronics Battery analyzers, chargers, rapid-testers and monitoring systems | Cadex Electronics

I do the same Ron07X5.

Cigarette lighter volt meter, smart charger if the X sits for more then 3 days.

I also replace the battery when voltage drops to 12.2 after sitting for 2 days.

12 yrs/200k miles and still on OE alternator, OE battery lasted 8 yrs, Autozone battery 4 yrs, just installed a Bosch unit.

BMW is not alone here, a lot of brands have issues when vehicles are not driven far enough to charge the battery. There have been a huge surge in adding in electronic features that all suck down power. The alternators have not increased in capacity to match. BMW went a more complicated route but getting 4.5 years out of a battery is about what you would expect. Ford, GM, Chrysler ll have had battery issues as well. There are many modules in the car and they all take power and they usually have an awake and a sleep mode. When they are awake, they take more power and it can be 30 to 45 minutes before they go to sleep. The battery a car has today is not much different than the battery they had over 20 years ago.

I think a 48-volt system will help things. You can use thinner wires as they can handle the same wattage compared to a 12 volt system. Say you need 48 watts on a 12 volt system. That would be 4 amps and would require a 15 AWG wire. On a 48 volt system, that would only be 1 amp and a 21 AWG wire can be used. A 48 volt system could help reduce power requirements; the hybrids aren't using 12-volts motors.

Another factor that has caused this; more gears. We have had four speeds for ages and then 5 speeds came around, then 6 speeds and not long after 7 to 10 speed transmissions. The reasoning has been better fuel mileage and how do you get better fuel mileage with more gears? Reduce the RPM while driving. In the city and not going fast enough for top gear; you will still find an 8 speed allowing lower RPM's than say a 6 speed. On the highway, you will find an 8 speed allows lower RPM's for going the same speed. Lower RPM's means lower alternator output since it to is spinning slower. Add more electronics in a vehicle that want power and you have to drive farther to replace what was consumed by the starter and the electronic while it was off.

The N63 has a 230 amp alternator. The N62 has an 180 amp alternator. Both of those ratings would be at 2500 RPM or higher. I can be in top gear and run at around 1000 to 1100 RPM doing around 45 to 50. On a 6 speed, that would be about 1300 RPM. To go 70 MPH; it is 1900 RPM on an 8 speed and 2100 RPM on a 6 speed. So while the alternator is larger, it has to be because the engine is spinning slower to do the same amount of work.

There are many factors why people are seeing battery issues now compared to earlier vehicles.

Field current increase will also increase alternator output.

I there any downside to frequent/regular external charging properly done? E. g., make sure the IBS can see the charge.

RTFM. i.e. it was what BMW recommends.

I've noticed that my alternator takes about 30 seconds for it to kick upon start of the car. Is this normal for the X5? In my other two cars, the alternator kicks on immdiately upon startup. Thanks.

Yes, that is also part of this design. In other vehicles, the alternator cannot be decoupled, on a BMW they can.

Thank you for the clarification.

Ok I bought a Jebsen voltmeter/car charger thingy as in the first post on this page, after all the worry on here and XBimmers. I am finding that the voltage displayed on there shows as follows:
-At start I sometimes see 11.9 but only for under 5 seconds. Then right up to 14.1-ish idling
-On the gas it shows anywhere from 12.3 - 14v, but for the vast majority of the time it is in the 14's.
-Coasting I don't see anything different than the above
-I have seen it show 11.9v once or twice, briefly

I haven't seen a correlation of lower voltage when on the gas, vs higher when coasting, BUT its hard to say because the main issue is that this device doesn't show Voltage continuously, it rotates between Voltage, Amps and Temp (useless info). Each is displayed for about 8-10 secs, so it is really hard to catch it on the V reading when driving a certain way to see if it varies.
I also can't tell if there is any delay in the readout, or if it is really real-time. I have seen it change while the V reading is displayed. So it may be real time.

I have only had it for a few days, and its hard to remember which voltages I saw match to what kind of acceleration/deceleration at that moment. However I can say that I am not seeing anything in the way of chronic low voltage readings. Some write-ups on this issue make it sound like the battery is not being charged much of the time, and I don't think that is the case. It may still be an issue overall, but I virtually never see it read under 14v.

I will continue to monitor and update this post if I can state my findings any more accurately.

Only thing I can state definitively is that if you are considering purchasing this thing, DON'T! Find one that displays Voltage and only voltage, all the time.
-Todd

Update to the previous post:
I had my battery replaced under warranty a couple months ago, I wasn't seeing any practical issue but the Jebsen was showing as low as 10.9v on startup for a few secs, until it rose to 13-14v. Actual voltmeter readings were only ~12 v at the battery terminals.
Anyway, the readings while driving above using the Jebsen all show similar but a few tenths of a Volt higher with the newer battery; 14.1v is now mid-14v...