Date: Tue, 1 Dec 1998 02:01:16 EST
Subject: [E36M3] Battery Maintenance - (Long if you read the whining too)
I see at least one E36M3 reader has a dead battery. I suspect there will be
several more as the weather turns colder, especially in '95 M3's. Three to
four years is about as long as you can expect a battery to survive, especially
in the South where heat is the concern. I expect my battery to die any day
too since I have a 9/95 production M3.
The following battery care advice probably won't help you guys with 2-3 year
old M3's but those of you with newer M3's might extend the life of your
batteries. Here goes nothing:
Unless BMW changed batteries in post 9/95 production M3's, you need to
routinely check the fluid level in BMW's OEM battery. So, if you haven't
checked the fluid level in your battery in the last 6 months, I recommend you
do it soon.
I have had to add about a quart (946 ml) of distilled water to my battery each
year. I've added a total of about 3 quarts of water to my battery in 3 years.
If my fluid loss is typical, I don't see how any OEM battery could last more
than 2 years. Once the cell plates are exposed, the battery is ruined.
I know my advice to check your battery's fluid level is a lot easier said than
done. It is a royal PITA. The caps to the cells screw off easy enough. I
think I use a quarter or a nickel as a screwdriver to screw the caps off.
Then you will need a pen light flashlight to check the fluid level. It is
hard to tell what the actual water level is. You practically have to stand on
your head to see the water. There is a plastic elbow that extends down into
the water. I guess the water level should be level with this elbow. I just
know each time I have checked my battery, the water level was well below this
"line." When you add water, it is next to impossible to tell when the water
spills over the plastic elbow. It might be easier to tell what the water
level is if you take the battery out of the dark trunk and set it on the
ground but who is going to go to that effort?
I am almost sure that everybody's OEM battery could use water. This summer
was very hot so I'll bet everybody's battery got "cooked" and some of the
water evaporated. Be sure to add distilled water or deionized water. But
don't do what I did the last time I added water. <grin> I am getting tired of
adding water every 6 months so the last time I said "the heck with it" and I
added water until the cells were almost completely full. I had the water
level well above the plastic elbow lines. About 30 minutes later I noticed
water dripping from under my trunk. The battery has some sort of an overflow
and the excessive battery acid ran out onto the ground. I now have a
permanent white streak etched into the floor of my garage.
OK, that is the end of my politically correct "advice." Now I am going to
start whining. I may get booted off the M3 mailing list by the List Mistress
for what I say but I'm going to whine anyway.
BMW engineers may know how to make a great handling and fun to drive car but
they have got a lot to learn about automotive battery technology. I've been
monkeying around cars for almost 30 years and I can't remember the last time I
ever saw a battery that "required maintenance." American and Japanese
automakers have been using "maintenance free" batteries since at least the
early '70's. In fact, every current battery I know of is permanently sealed.
There is no way to add water to virtually every other current car battery.
There may be a good reason why BMW chose to use a battery that has to be
opened up and checked every 6 months but I'll never know. It is beyond my
comprehension why a $45,000+ car doesn't have a maintenance free battery. I
could maybe see a Yugo with a cheap battery but a BMW luxury car? Surely, BMW
can't expect the typical owner to check the battery? Especially when it is
out of sight in the trunk or under the rear seat.
I love working on cars but I almost forget to check the battery in the trunk.
Checking the fluid level in a battery is something I haven't done in 20+
years. You just don't think about it.
I'll wager less than 1% of all BMW new car owners ever check there batteries.
I think the M3's battery is inconspicuous but I know the battery in some 5
Series cars is under the rear seat. It is difficult to even get to the
battery in a 5 Series model.
So, what am I going to do when my OEM battery finally dies? I know I will not
replace it with another "maintenance required" battery. I haven't seen any
public replies regarding replacement batteries to the E36M3 reader with the
dead battery so I don't know what the rest of you will suggest. I remember a
discussion on the big BMW Digest about sources for an M3 OEM battery.
Apparently there are very few sources for an original style battery. The
battery is very expensive too. List price from a dealer is something like
$170. My local Dallas club member who started the Crygest discussion found a
replacement battery from Interstate Batteries for about $120.
When my battery dies, I am going to buy a "sealed" maintenance free Sears
Diehard battery for about $80. No more of this constantly adding water for
me. I am not publicly recommending everybody should use a maintenance free
battery so don't flame me. Use whatever type of battery you want. No need to
tell me I am making a mistake either. I don't care if my car blows up the
first time I start it. At least I'll die a happy man knowing I'll never have
to add water to a battery again :-)
Talk to you later,
BMW CCA #131505
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