Tech Tip – A Cautionary Tale – Today’s car’s use a very specific type and size of battery. Unfortunately the days of visiting the local Sears to get a “DieHard” battery installed are over. Batteries are tricky things in today’s computerized cars, the incorrect battery type or mounting can damage your car, cause alternator failure or no start, even create an electrical fire (yes, really, see BMW recalls about that).

A byproduct of battery charging is hydrogen gas, which is highly explosive – think Hindenburg. So a trunk or interior mounted battery must be of the non-venting type, or have a proper vent hose installed, otherwise hydrogen gas can build up inside the compartment, and potentially cause an explosion. Reference – http://www.battcon.com/PapersFinal2002/VaccaroPaper2002.pdf

We found this arrangement this morning on a BMW 750iL, customer had paid a shop to “replace” the battery. Rather than using the correct BMW or Bosch battery, they installed a “AC Delco” (read GM) battery “braced” with a section of wood.

Aside from the safety issue, the battery is about nearly 1/2 the size of the correct battery. See that mounting hole on the right side of the battery tray, that is where the mounting bracket should be. Car presented with a list of electrical faults and problems, many of which can be traced to battery electrical problems.

We keep a large selection of the proper Bosch batteries in stock for your auto, all backed with a free 2 or 3 year replacement, and full warranty.