This can happen in your car...

Battery Safety & and Jump Starting
http://www.aa1car.com/library/battery_safety.htm

Battery Safety
http://www.rayvaughan.com/battery_safety.htm

Reverse Polarity Batteries
http://cr4.globalspec.com/article.pl?sid=06/06/12/0349222

14. WHAT ARE THE MYTHS ABOUT BATTERIES?
http://www.uuhome.de/william.darden/carfaq14.htm

Sight & Hearing Association:
Nearly 6,000 motorists each year suffer serious eye injuries or even blindness from working around batteries.
http://www.sightandhearing.org/news/healthissue/old/healthissueoct98.html

Battling Bad Batteries
http://www.scientificadvisory.com/batteries.html

Interstate Batteries Warranty Limitations
http://www.ibsa.com/www_2001/content/warranty/warranty_limitations.asp

Dear Tom and Ray:
http://www.cartalk.com/content/columns/Archive/2003/January/02.html

Batteries in Fact and Fiction
http://www.chem.hawaii.edu/uham/bat.html

Links in mercedesshop.com forums:

battery blew up - attention PEH
http://www.peachparts.com/shopforum/diesel-discussion/71351-battery-blew-up-attention-peh.html#post445147

Battery Explosion
http://www.peachparts.com/shopforum/tech-help/8118-battery-explosion.html#post34122

Battery noises
http://www.peachparts.com/shopforum/tech-help/9566-battery-noises.html#post41062

Dangerous battery explosions!
http://www.peachparts.com/shopforum/tech-help/83862-dangerous-battery-explosions-post1057860.html

battery exploded!
http://www.peachparts.com/shopforum/tech-help/8522-battery-exploded.html#post35913

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

You have too much time on your hands. Good info to post BTW.

__________________
Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

I always wondered why maintenance free batteries still need maintenance.. I think it is a scam perpatrated by battery companies to get you to buy more batteries.

__________________
83 300CDTurbo 307,000
2005 Honda Element 266,000
56 Nash Ambassador Country Club Special 34,000(under restoration presently)

http://www.peachparts.com/shopforum/car-audio-multimedia/125099-123-install-extreme-dynamat.html

That's pretty much what my battery looked like in the E420. It sounded like a baseball had been dropped on the trunk from a 20 story building.
A Bang so loud, I involuntarily shouted out an expletive.

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

boy am i glad i installed the drain that came with my group 49

i was afraid my old battery was going to explode when i was taking it out

Battery box probably helped hold the H gas in nice and close to the case

Scary!

I take it that you haven't used non-maintenance-free batteries. They need lots of maintenance. Checking your supposedly maintenance-free battery once a year is nothing. There really is a difference.