Battery Life

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Mike Fishwick
Joined: Fri 19 Jun, 2009 11:27
Posts: 2009

  Z3 roadster 2.8
Location: Daglan, France

Battery Life

Post by Mike Fishwick » Fri 23 Nov, 2018 12:36

I have just replaced the second battery on my twenty-year-old 2.8 Z3. The original American battery lasted twelve years, and the replacement Varta Silver eight years - what kind of life do others experience?

Like our other vehicles - cars, motorcycles and lawnmower - the batteries have always been connected to an automatic charger when the car is in its garage. The older (non low maintenance) types were regularly checked and their electrolyte levels topped up with de-mineralised water, as we live in an area of very hard water.

The electronics of my Gunsons chargers finally expired after about thirty years, being replaced by £10 'intellegent' chargers from China via Ebay, which charge at about 14 volts for short periods, during which they display the battery voltage and charging current, and between charge cycles show the percentage of full charge.

Our Golf TDI is eighteen years old, the original battery lasting for ten years, and the current eight-year-old OEM battery still seeming to be in its prime.
A Z3 is not just for Christmas - it's for life!

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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10053

  Z3 roadster 1.9
Location: Cheshire

Re: Battery Life

Post by Robert T » Fri 23 Nov, 2018 12:58

The original American battery failed after approx 2 years and was replaced under warranty with one from BMW Germany. This is still on the car over 17 years later. It is not kept on a battery tender. The car is my daily driver and I simply drive the car to keep it charged.

Cheers R.

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Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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motco
Joined: Tue 18 Aug, 2009 19:12
Posts: 675

  Z3 roadster 2.2i

Re: Battery Life

Post by motco » Fri 23 Nov, 2018 15:04

I have just changed mine after nine years of ownership. No idea how long before I bought the car the first change occurred but it wasn't the OEM as it had the name of an English town written on it! The car was seven years old when I bought it.

DC
Joined: Tue 15 Sep, 2009 18:31
Posts: 569

  Z3 roadster 1.9
Location: Inverness-shire

Re: Battery Life

Post by DC » Fri 23 Nov, 2018 16:16

I fitted a new BOSCH S5, capacity 77Ah, cold test current 780A with 5 years warranty early 2011. It was showing signs of reduced capacity early 2017 so I replaced with the same make and size in April 2017.
Previous to that the car came to me at around 11 years old (imported from Japan) with a Japanese battery so I presume it wasn't the original.
I don't use the car in the winter months when the roads have been salted, it lives in a dry but unheated garage which often goes below minus 5, maybe batteries last a bit longer in warmer climates?
I now use a CTEK during the winter when the car is garaged so that may help. Time will tell!
Dave.
Dave. 1998 Arctic Silver Z3 M44 1.9 Automatic

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motco
Joined: Tue 18 Aug, 2009 19:12
Posts: 675

  Z3 roadster 2.2i

Re: Battery Life

Post by motco » Sat 24 Nov, 2018 07:48

Mike you may be right about ambient temperatures. My Westfield has been garaged all of its life. For the first nine years with me it was in a detached brick garage of 1938 vintage (i.e. draughty), and for the past six in a 1970s integral one which is never below about 7ºC. The battery is disconnected 99% of the time and it is the one that was on the car in 2003 when I bought it.

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2129

  Z3 roadster 1.9

Re: Battery Life

Post by Del » Sat 24 Nov, 2018 11:58

I've not had good experience (failures between 1 to 4 years) with budget battery (unknown) brands - regardless of the care given to them. Personally, I have a soft spot for Exide.

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