[BXL4]

I'm on my original battery from August '14. Heidi has only 55k miles on her. I have no indications of a failing battery/faults/trouble cranking but I am planning a long trip into snow in a couple of weeks. Otherwise she is in Seattle weather - 40-70 degrees 320 days/yr.

My ODB II scanner showed this:
At Idle 14.86 Volts
Engine Off 12.09 Volts
Minimum while starting 8.60 Volts

Test conducted on a fully charged battery at 58 degrees ambient temp. I don't have the ability to recode a new battery or I'd do the replacement myself. Taking in to have someone else do it is a time commitment I'd rather avoid or at least put off.

Thanks for any wisdom folks can share.

[Billfitz]

Those readings are a bit on the low side. When fully charged you should get around 13v, but you have to be sure it's fully charged, which means when you hook it up to a charger the charger reads charged. The 14.86v reading is the alternator, not the battery. To be safe take your charger with you. If you don't own one you should. Bimmerlink can register a new battery. You can get 8 years/100k out of a battery, if you take care of it. That means putting it on a maintainer if you're not driving it for a week or more and/or only drive short distances and/or the overnight temperatures drop into the teens.

[Polo08816]

Originally Posted by Billfitz

Those readings are a bit on the low side. When fully charged you should get around 13v, but you have to be sure it's fully charged, which means when you hook it up to a charger the charger reads charged. The 14.86v reading is the alternator, not the battery. To be safe take your charger with you. If you don't own one you should. Bimmerlink can register a new battery. You can get 8 years/100k out of a battery, if you take care of it. That means putting it on a maintainer if you're not driving it for a week or more and/or only drive short distances and/or the overnight temperatures drop into the teens.

I'm at 8 years and 145k miles on the original battery. I have rarely used a battery charger despite having a CTEK MUS 25000. However, I drive the car every third day at the minimum and it's garaged so it doesn't get as cold or as hot as outdoor ambient temps.

[johnung]

Originally Posted by Billfitz

Those readings are a bit on the low side. When fully charged you should get around 13v, but you have to be sure it's fully charged, which means when you hook it up to a charger the charger reads charged. The 14.86v reading is the alternator, not the battery. To be safe take your charger with you. If you don't own one you should. Bimmerlink can register a new battery. You can get 8 years/100k out of a battery, if you take care of it. That means putting it on a maintainer if you're not driving it for a week or more and/or only drive short distances and/or the overnight temperatures drop into the teens.

I've had good luck carrying this battery jumper. Really helps being able to jump weak batteries in the cold, especially ones that are really dead from not being driven. Charges up easily with an included USB cable.

NOCO Boost Plus GB40 1000 Amp 12-Volt UltraSafe Lithium Jump Starter Box, Car Battery Booster Pack, Portable Power Bank Charger, and Jumper Cables For Up To 6-Liter Gasoline and 3-Liter Diesel Engines https://www.amazon.com/dp/B015TKUPIC...UTF8&psc=1

I also have this 110v plugin battery charger. Helps to get batteries fully charged up even if they are very depleted.

NOCO GENIUS10, 10-Amp Fully-Automatic Smart Charger, 6V and 12V Battery Charger, Battery Maintainer, Trickle Charger, and Battery Desulfator with Temperature Compensation https://www.amazon.com/dp/B07W3QT226...UTF8&psc=1

[BXL4]

Originally Posted by johnung

I've had good luck carrying this battery jumper. Really helps being able to jump weak batteries in the cold, especially ones that are really dead from not being driven. Charges up easily with an included USB cable.

NOCO Boost Plus GB40 1000 Amp 12-Volt UltraSafe Lithium Jump Starter Box, Car Battery Booster Pack, Portable Power Bank Charger, and Jumper Cables For Up To 6-Liter Gasoline and 3-Liter Diesel Engines https://www.amazon.com/dp/B015TKUPIC...UTF8&psc=1

I also have this 110v plugin battery charger. Helps to get batteries fully charged up even if they are very depleted.

NOCO GENIUS10, 10-Amp Fully-Automatic Smart Charger, 6V and 12V Battery Charger, Battery Maintainer, Trickle Charger, and Battery Desulfator with Temperature Compensation https://www.amazon.com/dp/B07W3QT226...UTF8&psc=1

I have a trickle charger that I can pack but didn't think about a booster starter battery if things get wimpy en route. Just bought that. I'll be good to go now. Thanks to all for your insights

[cfm56d7b]

With batteries, the mileage truly varies. The battery on my 2017 440i GC with 30K miles was replaced by the dealer under warranty after several codes (due to low voltage) were triggered and stored. Yet others have driven on OEM battery for years and 70K+ miles.

Are there any stored codes that might indicate the battery isn't as healthy as one would expected?

[Billfitz]

A battery that's low on charge can cause a number of codes to be thrown, but that doesn't necessarily mean it's a bad battery, it just means it was low on charge. That can happen for a number of reasons, including infrequent use, short trips, very cold weather and more. One pernicious culprit is the instrument panel, which is known to suck a battery drier than a hungry vampire.

[ams62]

Hi - I'm looking to replace the OEM car battery on my 2015 335D
The Original BM battery is 90Ah and 900CCA - the closest equivalent I can find is the Bosch AGM 019 Car Battery - S5 A13, or the EXIDE EK950 019AGM, both of which are 95AH but only 850CCA. Will the 850CCA be sufficient for a 335D - anyone replaced their OEM with a different car battery ?

Comments/advice appreciated as both of these are approx £100 cheaper than OEM BMW batter at £233 and that's before fitting - which I'm looking to do myself.

[Billfitz]

1. Don't post the same question in more than one forum section.
2. Don't ask a question unrelated to the thread title. Start a new thread.