[iwinit]

I drive my 2011 535i 30 miles a day and 6 days a week. It seems not enough to keep the battery fully charged. I check the battery status every Friday night and charge the battery fully. Each time it has only about 70% charge left. Is it normal? How many miles do you need to drive everyday to keep the battery fully charged?

[gatoman39]

Sounds normal to me. I drive 20-25 miles a day, not much. I got a battery tender that I use occasionally per the suggestion of my service adviser when I went in for my annual low mileage oil change. As a preventive measure, it's dirt cheap insurance.

[HUFFY]

Originally Posted by iwinit

I drive my 2011 535i 30 miles a day and 6 days a week. It seems not enough to keep the battery fully charged. I check the battery status every Friday night and charge the battery fully. Each time it has only about 70% charge left. Is it normal? How many miles do you need to drive everyday to keep the battery fully charged?

30 Miles a day should be loads from an alternater that can deliver 20/30 amps. Either the battery requires changing or the charging system is faulty, my money is on a faulty battery.

[wessew10]

I have a 2011 550i. I have had it for 12 months now. I put on about the same mileage annually. I have not had any issues with the battery other than a fault reading on battery condition which turned out to be a software issue. The software was updated about two months ago and no more battery condition issues. I do not think you should have to use a battery tender for this kind of useage. If you feel you do, it might be masking another issue as noted by HUFFY. I am not sure the battery needs to stay at 100% charge in any case. The vehicle is using a small amount of electricity even when parked at night so maintaining full charge is probably not reasonable unless you have just gone on an extended drive.

[iwinit]

Thanks for all the advises. I'll keep a close eye on the battery. I don't think the dealer will replace the battery for me under warranty because it is still working and I haven't got any error messages. I just don't understand why the battery is only at 70% charge after one week's use of 30 miles a day. My wife drives her old Toyota Highlander for much less miles and its battery is always close to full charge.

[mspeasl]

We have over 16K on our 2011 528 and have never had any battery problems.

[AC_S5]

I think the car will still function with a 70% battery, same goes for your cell phone, it will never be at 100% cause the phone will still function with less then a 100% battery.

I guess that's what they mean by efficient dynamic and smart battery management for your car, storing un-used battery power in a battery is wastage perhaps.

[iwinit]

So, the battery is not fully charged on purpose to maximize MPG. Can someone confirm that?

I thought the best way to extend a car battery life was to keep it fully charged or give it a full charge periodically. Am I doing the wrong thing to charge the battery every Friday with a battery charger?

Thanks.

[Needsdecaf]

Originally Posted by iwinit

So, the battery is not fully charged on purpose to maximize MPG. Can someone confirm that?

The car has a regenerative alternator which charges on the overrun. The battery will operate at a lower level of charge to prevent overcharging if you encounter extended periods of coasting.

[gatoman39]

Originally Posted by iwinit

So, the battery is not fully charged on purpose to maximize MPG. Can someone confirm that?

I thought the best way to extend a car battery life was to keep it fully charged or give it a full charge periodically. Am I doing the wrong thing to charge the battery every Friday with a battery charger?

Thanks.

I don't think there's anything wrong with what you're doing so long as it's a smart charger and not a trickle charger. However, every week for a car that gets driven all the time is probably unnecessary. Once a month is more than enough.

[iwinit]

Originally Posted by gatoman39

I don't think there's anything wrong with what you're doing so long as it's a smart charger and not a trickle charger. However, every week for a car that gets driven all the time is probably unnecessary. Once a month is more than enough.

Yes, it is a smart charger. Schumacher XC103 to be exactly. I think I get to know the battery a little bit better now. Last night, I charged it full. This morning when I started the car, I got an error message "Increased Battery Discharge Occurred". It's the first time I got this error message. My car was locked and parked in garage last night with all lights off as usual. No idea what happened. But from now on, I will not charge the battery so frequently. Maybe just once every 1-2 months. Maybe BMW battery is so special that keeping it at a high charge level will actually harm it.

[gatoman39]

Originally Posted by iwinit

Yes, it is a smart charger. Schumacher XC103 to be exactly. I think I get to know the battery a little bit better now. Last night, I charged it full. This morning when I started the car, I got an error message "Increased Battery Discharge Occurred". It's the first time I got this error message. My car was locked and parked in garage last night with all lights off as usual. No idea what happened. But from now on, I will not charge the battery so frequently. Maybe just once every 1-2 months. Maybe BMW battery is so special that keeping it at a high charge level will actually harm it.

When the XC103 asks you Battery type, what's your input?
When it asks Charge rate what's your input?

[iwinit]

Originally Posted by gatoman39

When the XC103 asks you Battery type, what's your input?
When it asks Charge rate what's your input?

I select AGM battery type and 5 amp charge mode.

[nicolak]

I am probably going to jinx myself but I only use my 550 once a week. Have never seen any error messages and I have had the same experience and patterns with the previous BMW's I have owned. Never used a charger on any of them. Just put the 5 series away today and wont start it again until mid April, crossing fingers the good luck pattern continues.

[gatoman39]

Originally Posted by iwinit

I select AGM battery type and 5 amp charge mode.

Is the 5amp charge mode the turtle or the snowflake?

[iwinit]

Originally Posted by gatoman39

Is the 5amp charge mode the turtle or the snowflake?

5 amp is the turtle / slow charging. Snowflake is 3 amp / maintenance. I don't use the maintenance mode unless the battery is already close to full charge. Manual says maintenance mode should not be used to charge a large battery or depleted battery. But it can be used to maintain a large battery which is already fully charged. No matter what mode I choose, it will automatically go to overflow mode (2 amp) after full charge.

[AC_S5]

Originally Posted by iwinit

Yes, it is a smart charger. Schumacher XC103 to be exactly. I think I get to know the battery a little bit better now. Last night, I charged it full. This morning when I started the car, I got an error message "Increased Battery Discharge Occurred". It's the first time I got this error message. My car was locked and parked in garage last night with all lights off as usual. No idea what happened. But from now on, I will not charge the battery so frequently. Maybe just once every 1-2 months. Maybe BMW battery is so special that keeping it at a high charge level will actually harm it.

Well since you check the battery everytime is 70% full, then it's an indication that BMW intended to keep it only at 70% full and having that error message means the car is actually discharging the excessive power that is store in the battery in order to prevent overcharging the battery when the car is in operation.

I wouldn't worry too much, I don't drive much in Hong Kong and my battery still last 5 years. But then the demand on a battery will change depending on the surrounding condition, ie. if you live in colder places, the battery will require more power on start up.

Those chargers are more suitable if you are like a car collector where you have alot of cars in your garage that you don't drive half the time if you ask me. How much is the charger? If it's quite expensive, I think is better to leave the battery as it is and replace it when is no good, I would think is about the same amount of money then buying a fancy charger just to protect your battery.

[gatoman39]

Originally Posted by iwinit

5 amp is the turtle / slow charging. Snowflake is 3 amp / maintenance. I don't use the maintenance mode unless the battery is already close to full charge. Manual says maintenance mode should not be used to charge a large battery or depleted battery. But it can be used to maintain a large battery which is already fully charged. No matter what mode I choose, it will automatically go to overflow mode (2 amp) after full charge.

OK, you are definitely using the charger correctly, but I'm not sure why you are getting the error message. We have similar driving patterns but I charge the battery once every other month and I use the Deltran battery tender plus.

[HUFFY]

Originally Posted by gatoman39

OK, you are definitely using the charger correctly, but I'm not sure why you are getting the error message. We have similar driving patterns but I charge the battery once every other month and I use the Deltran battery tender plus.

I had a 318dm sport and it was 'mothballed' for six months whilst I was abroard. I connected a smart charger (just in case) for the full 6 months and left it swithed on all the six months. On my return the car was fine with no error messages. Most batterys ie, nicad, lithium, mercury and car batterys like to be used to the full. ie charged then disscharged. Topping up to keep the 12 volts (13.2V). is not a good thing for a long life of a car battery. Once again the alternator is well able to charge at 10 or even 15 amps if need be. Its a good idea to switch everything on now and then whilst driving to drain the battery. The alternator will then charge at a higher rate. This is good for the battery and ensures a long life for it.

[gatoman39]

Originally Posted by HUFFY

I had a 318dm sport and it was 'mothballed' for six months whilst I was abroard. I connected a smart charger (just in case) for the full 6 months and left it swithed on all the six months. On my return the car was fine with no error messages. Most batterys ie, nicad, lithium, mercury and car batterys like to be used to the full. ie charged then disscharged. Topping up to keep the 12 volts (13.2V). is not a good thing for a long life of a car battery. Once again the alternator is well able to charge at 10 or even 15 amps if need be. Its a good idea to switch everything on now and then whilst driving to drain the battery. The alternator will then charge at a higher rate. This is good for the battery and ensures a long life for it.

When i went in for my yearly oil change the SA asked me about my driving habits and suggested I get the trickle charger. He said he has seen way too many irate people with dead batteries after just a year or 2 in service. I hear what you're saying and in principle one shouldn't have battery issue, but in practice there seems to case for the charger.

[1HOT BMR]

It's just amazing to me that we all put up with this crap because we like and bought a new 5 series. Having to "maintain" the battery so we can drive the car? Give me a break!

[HighlandPete]

Originally Posted by 1HOT BMR

It's just amazing to me that we all put up with this crap because we like and bought a new 5 series. Having to "maintain" the battery so we can drive the car? Give me a break!

Thank our dear old EU regulations. BMW have to meet EU targets for CO2 emissions, as a 'product mix' average. Power management and ED features, (however flawed for some of our driving cycles) are one of BMW's key tools to prevent fines and penalties. Mercedes have similat target issues due to the product mix.

Look at it this way, most of Europe drive 520d models, this allows some of you to drive 550i's. I've a feeling if the majority didn't drive 520d's, the 550i would be extinct. Virtually is in the UK anyway, we've been priced out of them, with fuel duty and taxes. Even the 535i is not popular, simply due to the taxation and fuel costs.

Back to the issue of battery condition, some of us won't be driving the ideal type of mileage, or getting enough braking/overruns, to keep the alternator charging time up, so bound to find limitations in use.

I know here in the UK, it is becoming common for battery issues, as use doesn't allow enough charge time for the battery. Our average journey length in the UK is so small, some surveys indicate it is only about 3 - 5 miles. So no hope is there for a fully charged battery anyway, let alone any ED technology. Part of the problem is due to the heavy electrical loads, higher specced cars typically have more battery drain issues.

HighlandPete