Battery question

spelk3 · 07-28-2021, 06:12 PM

My X3 is around 5 years old and I am thinking of replacing the battery due to age as preventative maintenance.

How do the batteries on the X3 die? Do they slowly decrease in capacity or do they just die? My Harley recently had the battery just die while I was riding. It started up fine, lights dimmed a little while I was riding then totally dead battery. Couldn’t restart and had to get it towed.

pungo · 07-28-2021, 07:17 PM

I've had them die all of the sudden (I believe shorted plates).
I've had them slowly get weaker and weaker, voltage keeps dropping week by week.
I've had them die in 3 years
I've had them die in 10 years
I have a red top over 20 years old, some kinda freak

I've never replaced one as preventative maintenance, only when weak or dead. If I was going on a long trip and had a 5-8 yr old battery and the voltage was not above 70%, I might consider replacing it.

spelk3 · 07-28-2021, 07:27 PM

Mine is at 12.1 volts after sitting for two days. I’ve read that a good battery won’t drop below 12.4 volts. After seeing it at 11.6 volts I keep it on a battery maintainer if it’s going to sit for more than a few days.

Wgosma · 07-28-2021, 07:30 PM

Have a shop load test the battery, that should get you definitive info about its health, eliminate the guesswork.

pungo · 07-28-2021, 10:40 PM

Quote:

Originally Posted by spelk3

Mine is at 12.1 volts after sitting for two days. I’ve read that a good battery won’t drop below 12.4 volts. After seeing it at 11.6 volts I keep it on a battery maintainer if it’s going to sit for more than a few days.

Does your maintainer have a Desulfator? Many times, running a Desulfator for several days to a week or so can restore battery health if the battery is sulfated. The AGM in my Z4MC is over 10 years old, I believe due to my Maintenance Charger-Desulfator. Like I said, my Optima red top is over 20 years old using the Maintenance Charger-Desulfator, but I think that thing is a freak.

spelk3 · 07-28-2021, 10:53 PM

Quote:

Originally Posted by pungo

Does your maintainer have a Desulfator? Many times, running a Desulfator for several days to a week or so can restore battery health if the battery is sulfated. The AGM in my Z4MC is over 10 years old, I believe due to my Maintenance Charger-Desulfator. Like I said, my Optima red top is over 20 years old using the Maintenance Charger-Desulfator, but I think that thing is a freak.

I have a CTEK MXS 5.0. I have run one recondition cycle on the X3 battery. CTEK manual says to recondition once a year.

I haven’t been able to hook it up for about a month. I had some serious back pain and could barely walk. Just had surgery and a second hospital stay last week.

Weslsew · 07-29-2021, 07:46 AM

My original battery is going on 8 years... I do think that charging the battery up with a charger/maintainer every once in a while helps. I don't think the BMW does a good job of keeping the battery charged, I think the charging system is designed more for fuel efficiency than battery longevity.

I have a theory that the car tries to just "maintain" the battery's level. If the battery charge drops low or if the car is sitting for some time, the car won't charge it fully back up, but rather will just try to maintain it at that level. Therefore occasionally giving it a full charge via a slow trickle charger every once in a while (every oil change?) helps maintain its life

kevink1 · 07-30-2021, 09:24 PM

From what I've read it keeps it at something like 80%, assuming that it was coded properly and the battery is functioning. That leaves storage for when you do braking and captures some of the energy to the battery.

If the car never charged the battery up, then it wouldn't really last long at all. Any time you left it in accessory mode, or just undriven (car keeps some electronics going to detect remote keys, etc), it would drop. And if the car didn't charge it above that level, it would continue to go down.

Sandy5454 · 08-01-2021, 02:10 AM

In normal regular use I have never had to charge a car battery. However I find that my X3 and my wifes 1 series both lose battery charge after sitting unused for two weeks or more. I now regularly check the batteries using a BT battery monitor and keep them charged using a smart battery charger.

CAX3 · 08-01-2021, 11:18 AM

Get a battery tester/charger, or take it to a shop and have them test it for you.

07-28-2021, 06:12 PM	#1
spelk3 Confused Member 4 Rep 34 Posts Drives: BMW X3,i3,i3; Harley FLSTF Join Date: Dec 2019 Location: SF Bay Area, CA iTrader: (0)	Battery question My X3 is around 5 years old and I am thinking of replacing the battery due to age as preventative maintenance. How do the batteries on the X3 die? Do they slowly decrease in capacity or do they just die? My Harley recently had the battery just die while I was riding. It started up fine, lights dimmed a little while I was riding then totally dead battery. Couldn’t restart and had to get it towed.
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07-28-2021, 07:17 PM	#2
pungo Colonel 880 Rep 2,547 Posts Drives: Z4MC-X3-35i-525i, Corrado G60 Join Date: Nov 2007 Location: MD iTrader: (5) Garage List 2011 BMW X3 x35i [0.00] 2001 BMW 525i [0.00] 2007 BMW Z4 M Coupe [8.76]	I've had them die all of the sudden (I believe shorted plates). I've had them slowly get weaker and weaker, voltage keeps dropping week by week. I've had them die in 3 years I've had them die in 10 years I have a red top over 20 years old, some kinda freak I've never replaced one as preventative maintenance, only when weak or dead. If I was going on a long trip and had a 5-8 yr old battery and the voltage was not above 70%, I might consider replacing it.
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07-28-2021, 07:27 PM	#3
spelk3 Confused Member 4 Rep 34 Posts Drives: BMW X3,i3,i3; Harley FLSTF Join Date: Dec 2019 Location: SF Bay Area, CA iTrader: (0)	Mine is at 12.1 volts after sitting for two days. I’ve read that a good battery won’t drop below 12.4 volts. After seeing it at 11.6 volts I keep it on a battery maintainer if it’s going to sit for more than a few days.
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07-28-2021, 07:30 PM	#4
Wgosma Lieutenant Colonel 806 Rep 1,906 Posts Drives: 2012 F25 X3 28i (N52) Join Date: Sep 2018 Location: Northern Nevada iTrader: (0)	Have a shop load test the battery, that should get you definitive info about its health, eliminate the guesswork.
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07-29-2021, 07:46 AM	#7
Weslsew Enlisted Member 3 Rep 49 Posts Drives: F25 X3 35i Join Date: Jun 2019 Location: FL iTrader: (0)	My original battery is going on 8 years... I do think that charging the battery up with a charger/maintainer every once in a while helps. I don't think the BMW does a good job of keeping the battery charged, I think the charging system is designed more for fuel efficiency than battery longevity. I have a theory that the car tries to just "maintain" the battery's level. If the battery charge drops low or if the car is sitting for some time, the car won't charge it fully back up, but rather will just try to maintain it at that level. Therefore occasionally giving it a full charge via a slow trickle charger every once in a while (every oil change?) helps maintain its life
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07-30-2021, 09:24 PM	#8
kevink1 Second Lieutenant 23 Rep 253 Posts Drives: 2015 X3 xDrive28d Join Date: Nov 2013 Location: Oklahoma iTrader: (0)	From what I've read it keeps it at something like 80%, assuming that it was coded properly and the battery is functioning. That leaves storage for when you do braking and captures some of the energy to the battery. If the car never charged the battery up, then it wouldn't really last long at all. Any time you left it in accessory mode, or just undriven (car keeps some electronics going to detect remote keys, etc), it would drop. And if the car didn't charge it above that level, it would continue to go down.
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08-01-2021, 02:10 AM	#9
Sandy5454 Sandy 6 Rep 29 Posts Drives: BMW X3 30D Join Date: May 2020 Location: UK iTrader: (0) Garage List 2016 BMW X3 [0.00]	In normal regular use I have never had to charge a car battery. However I find that my X3 and my wifes 1 series both lose battery charge after sitting unused for two weeks or more. I now regularly check the batteries using a BT battery monitor and keep them charged using a smart battery charger.
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08-01-2021, 11:18 AM	#10
CAX3 New Member 6 Rep 20 Posts Drives: 2015 X-3 Xdrive35i Join Date: Jun 2021 Location: California iTrader: (0)	Get a battery tester/charger, or take it to a shop and have them test it for you.
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