Need to buy a battery. Opinions?

[87Shark]

Like the header says, I need to buy a battery. Thinking Optima, but which one should I go with? I have a red top in my truck, but I hear good things about the yellow tops also. She's not a daily driver, more of a weekend runner. Opinions? Thanks in advance.

[Bhart]

Optima might not have a battery the correct size to fit the car.

I got a conventional battery sized to fit the M6 battery box so the cables fit correctly and the mounting hold down worked.

IMHO, less hassle in the long run.

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[Pod]

I bought an Optima blue battery for my Jeep a couple of years ago. Its really good. Whilst away on a two-week holiday recently, the interior lights stayed on for some reason or other (usual Grand Cherokee electrical gremlins). Whilst it wasn't quite able to start the car, it did try and very nearly managed it!

[Ronnie Wilson]

Hi guys.
I went to my local Bmw dealership in the UK. Williams Bmw Liverpool. The parts staff are great. They looked into what type of battery my 1986 635csi should have had from it's vin and ordered me one from Bmw. What I'm saying is that your local Bmw dealer will tell you what type should be fitted, it also comes with a warranty. The cost was around the same as getting one independent supplier.

[hornhospital]

That's completely different than what you'll find in the U.S. The parts department will likely be just as friendly and helpful, but the cost will be 2x what you'll pay at an independent battery supplier, and you'll get the same or better warranty from the independent.

[Ronnie Wilson]

Hi, yes totally understand. Some items from Bmw can be very expensive and other items you think may be expensive will not be. For me I just like to keep my car as close to factory as possible. For other owners this mite not matter as much. When I first got my car the first item to change was the battery. I got one from an independent supplier and the terminals where the wrong way round, so couldn't connect the + and -. From then on I thought I'll try and get close to factory as possible.

[Brucey]

.... it also comes with a warranty. The cost was around the same as getting one independent supplier.

-details?

cheers

[Brucey]

FWIW all E24 models use the same size battery

-278mm long
-175mm wide
-190mm high

-Flanged base for clamping

-DIN standard round posts, +ve terminal located front right.

- 680A cold cranking (SAE)
- 72 Ah capacity
- 12V

This type of battery is usually known as a 'TYPE 096 CAR BATTERY'. If you search vendors for this specification you will obtain the correct battery that will fit properly.

A Type 100 battery can be a suitable alternative; this is identical bar the height dimension, which is 175mm instead of 190mm. However some (but not all) Type 100 batteries have a 650A CCA rating.

NB; there are a couple of things worth knowing;

1) modern e.g. 'calcium technology' batteries will not charge fully in an E24 unless a 14.2V regulator is installed in the alternator in place of the original 13.8V regulator. If charged to only 13.8V your '72Ah battery' will only have a ~40Ah capacity when new, which will only get less with time. After a few weeks or months of this, the battery will be permanently damaged and will no longer take a full charge at 14.2V.

2) Most E24 have a parasitic load on the battery of between 50 and 70mA; this will knacker any battery (no matter what type) if you leave the battery connected to the car and don't use it often enough. Typically when a battery is new, the car will still start OK after a couple of weeks idle, but after a year or two of this treatment, the battery will be sulphated up and will have a severely reduced capacity.

The combination of both these things can pretty much destroy a battery (of any quality) inside a year on an E24.

If you have a warranty, if you can do so, be sure to have the supplier test your battery before the warranty expires. My guess is that it will fail the CCA test even if it seems OK in normal use.

I have a 14.2V regulator fitted (which BTW also makes your headlights brighter, bonus!) and I leave my battery disconnected (and/or on a small solar panel to keep it topped up) when the car is not in regular use. Before I started doing that the typical battery life was around 3 years. The present battery is about 8 years old and still seems to be fine.

If I needed another battery, I think I can obtain a Type 096 mail order with a 4 year warranty for a keen price that none of my local suppliers can touch.

However there is a benefit in using a local supplier; I won't have to ship a heavy battery in the event of a warranty claim. The last battery I bought (not for my E24) came from a local supplier for this reason, but my plan backfired; they went out of business....

Hey ho....

cheers

[Ronnie Wilson]

Hi Brucey,
Please find attached invoice for battery. If you can't see the part number on the invoice it is B61.21.2.158.122. I also have my battery connected to a ctec battery charger available from Bmw part number B61.43.2.334.070 which not only keeps the battery changed But conditions the battery keeping it in perfect condition. It also comes with the Bmw logo on it. I have it permanent connected to the battery via a connection plug. So once you have put your car back in the garage simply pop the bonnet/hood and plug in. See attached picture. Cost me £78 available online

[Brucey]

£85? -that is about what I would pay locally for a similar battery (not from Halfords.... ). However they appear to have sold you a smaller capacity 65Ah battery; the usual Type 096 battery has a ~72Ah rating.

A few minutes searching found me this;

https://advancedbatterysupplies.co.uk/p ... r-battery/

which is a type 096 battery with a 4-year warranty for £50 delivered.

E-bay shows type 096 batteries starting at about £45 (delivered) with a quality Yuasa YBX 3000 series Type 096 (with a four year warranty) starting from about £65 delivered.

cheers

[BlackBetty]

Hey Brucey, you wouldnt happen to have a part number for that 14.2 v regulator, would you?
Pete

[zinnocoupe]

Yikes, I've not heard this before Brucey

1) modern e.g. 'calcium technology' batteries will not charge fully in an E24 unless a 14.2V regulator is installed in the alternator in place of the original 13.8V regulator. If charged to only 13.8V your '72Ah battery' will only have a ~40Ah capacity when new, which will only get less with time. After a few weeks or months of this, the battery will be permanently damaged and will no longer take a full charge at 14.2V.

2) Most E24 have a parasitic load on the battery of between 50 and 70mA; this will knacker any battery (no matter what type) if you leave the battery connected to the car and don't use it often enough. Typically when a battery is new, the car will still start OK after a couple of weeks idle, but after a year or two of this treatment, the battery will be sulphated up and will have a severely reduced capacity.

The combination of both these things can pretty much destroy a battery (of any quality) inside a year on an E24.

I would be interested in the no. for the 14.2 reg as well.

Cheers Dave

[dwcains]

Dave Barton sells the higher voltage VR's.

http://www.davebarton.com/AdjustableVoltage.html

I've had a few (I ordered the fixed output, rather than an adjustable VR), and one failed pretty quickly, charging at barely 13V when it warmed up. I contacted Dave, and he initially denied a problem, but after another contact he sent me a replacement. I haven't put a lot of miles on the current one, but it seems to be within spec and here are some voltage readings:

engine off, battery rested overnight:


engine at idle, engine at ambient temp:


engine at idle, engine fully warmed after driving for ~30 minutes:


As you can see, there's a fairly substantial voltage drop as the engine warms, but voltage output seems to remain stable at that level. When I measured an original Bosch VR, initial output was 13.6V, with a smaller drop down to ~13.4V with a warm engine.

[

I should also mention I've had several other higher voltage VR's for more than a decade in my two Alfa's, and they've worked well. I bought them from a different vendor, but they are the same Chinese-made Transpo brand, and they were the adjustable type. Lots of Bosch and VDO components on the Alfa's, just like our BMW's, and there have been no issues with running the voltage at just over 14V. But, of course, the headlights are nrighter, and the accessories (power windows, defroster fan, wipers, etc. ) all work better. I've read that the modern battery chemistry also requires a higher voltage to take a full charge.

[Brucey]

IIRC the later Bosch voltage regulators fitted to some Volvos are also rated at the higher voltage.

If you fancy a bit of DIY, you could modify your voltage regulator eg as per what I did here;

viewtopic.php?f=2&t=6352

cheers

[Bhart]

IIRC the later Bosch voltage regulators fitted to some Volvos are also rated at the higher voltage.

cheers

Is there not a later model BMW alternator that would run at 14 volts (+-) that could be substituted and fitted without (serious) modification?

[dwcains]

The voltage is determined by the voltage regulator, but you could also install a later alternator, such as I did on my '85. What that buys you is more current output, though, which you may or may not need. The original on my '85 was an 80-amp unit, and I replaced it with a 115-amp unit ('88 535is), and I also used the higher voltage VR. I wanted the extra amperage for an upgraded A/C condensor fan, headlights, and audio system.

EDIT: I think your M6 already has that 115-amp alternator.

[87Shark]

It seems that we got a little off topic. All great information, some of which I will be using, but the question remains.....some more battery info Please! What do you have? Good, bad, etc. Need to get one this coming week/weekend, so I need input. Living in the USA's version of temperature Hell (Arizona) heat is an issue.
Thanks

[dwcains]

I've been buying WalMart batteries for maybe 30 years, mostly because of the convenience and price, but they certainly seem to last a good, long time here in S. FL. Never lesss than 6 or 7 years, as I recall. I have an Everstart Maxx-H5 in my 635, and it fits the available space perfectly. Sometimes I don't start the car for maybe a month, and it always starts as if it was just run the day before. For $100 I don't see how you can go wrong, and when I had Optima Red's in my two Alfa's, which are driven much less frequently, both batteries failed inside two years.

[BenM635i]

Just broken a habit of a lifetime and bought the cheapest battery in the world, £45 delivered to the door.

Previousely have always stuck to Bosch or Varta and for the BMW its been Bosch 100amp hour ones up to now. However they have not lasted beyond a couple of years (not been used enough) so I can confirm if you dont use the car and charge it at 13.8V and have a drain then the battery will definitely fail no matter how much it costs.

So went on eBay, found a type 096/100 delivered to door for £45 with a 4 year guarantee so what can possibly go wrong? Besides, car has sat on a CTEK for the last year whenever in the garage so dont suppose the quality of the battery matters all that much now.

Cheap n cheerful, the legendary battery brand that is 'ProBat Battery':

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[Pod]

Snap! I had a couple of these Probats delivered yesterday for my 840. Total cost £71.90 (next day delivery). I'm hopeful they will be better than the two new premium batteries which were fitted to the car just before I bought it 18 months ago, which lasted about 9 months and cost over £200.

The Probats were described as "leisure batteries" suitable for deep cycling - which may just suit the 840 with its power-hungry security system. Keeping my fingers crossed

[sharkfan]

The four year warranty will be tricky to enact if the ebay seller disappears won't it?

I have always used Halfords for batteries; you pay a little more but the warranty is absolutely quibble free provided you keep the receipt, which I do, in the car.

I've had four or five batteries replaced right near the end of their warranty over the years so when the I'm-going-to-keep-it-a-long-time-but-don't-use-it-every-day E38 needed a new battery last year I bought a 'Lifetime Guarantee' Yuasa battery from Halfords - the small print says they'll just keep replacing it for the life of the car.

[dwcains]

Another option for those in the US is to buy a battery from CostCo, as I've heard they'll replace a bad one with no issues, almost forever. I think they sell Interstate, which is considered a premium brand. I don't have a CostCo membership, though, so this is just hearsay.

[Brucey]

re 'leisure batteries'; these have a different internal design and IIRC this can affect the CCA rating. I'd be interested to hear if the CCA rating of the leisure batteries above is the same as that of other batteries.

BTW a garaged car in a warm climate will start with even a feeble battery connected to it.
However in cold weather the torque required to crank an engine can be double or more, and the output of a cold battery can be half or less.

This means that a battery that 'lasts 6-7 years in Florida' might well be completely kippered in 2-3 years of use in colder climes.

Re an e-bay vendor warranty; I agree this is a concern, but some warranties are manufacturer-based, not vendor-based, so it may be possible to get the warranty enforced even if the vendor goes out of business. At least as much a concern would be the postage cost for a failed battery, if it needs to go back to a remote vendor.

cheers

[Da_Hose]

Here is what I did to upgrade the battery in my M6.

viewtopic.php?t=25500

Jose

[BenM635i]

Well the wonder that is 'ProBat' worked at least once.. started like a dream today.

For £45 cant go too far wrong, about half the price of a proper brand at the local car shop or Halfords.

Brucey, i am sure you will love yours too - the future is Probat.