Date registered: Nov 2002
Vehicle: 10 GLK 350 4Matic
Location: Sonoma County CA
Mentioned: 0 Post(s)
Quoted: 8 Post(s)
RE: battery death warning
Batteries are tested ( even today[:)]) by measuring their standing voltage - at rest not having been charged or starting a car in the last ten minutes. They should read about 13.75 volts.
They are then discharged at a consistent rapid pace for 5 to 10 minutes. They ending voltage is measured. If in that short time it drops below 12.25 volts it's considered on its last legs. A good parts store or auto battery store can do this test - but realize a lot of them are anxious to sell you something.
The typical lead-calcium flooded cell ( your typical starting type battery) signals it's near the end of life by bouncing back slowly and not hitting the old peaks. It will crank the car a little more slowly and in stop and go trips and will seem to not come back up to charge fast enough.
The Optima is an excellent battery. It is a sealed spiral cell battery with very low amounts of acid in a mat wrapped between the plates. It can give a lot of power for its size and can have a long life. A couple things - they are very expensive for what they give you and they are very sensitive to overcharging. They can lose their very small amount of electrolyte through a pressure valve if the voltage isn't carefully controlled. Most Mercedes with microprocessor based voltage management systems should be OK ( if you don't mind the $$$) but the older relay based systems - such as a 240D may not be up to the task.[xx(] Your typical DieHard or Interstate batteries are much better at this - and at 1/3 the price.
Check yor local Interstate distributor. They commonly sell seconds and blem's for $30 or so. It's an incredible deal on a very good battery. They can't sell first runs because that conflicts with their retail shops but do you really care if the label on a battery is a little crooked? If that's not practical your best deals are a Sears sale on DieHards,or WalMart, PepBoys or Costco...
Buy all the AmpHour and Cold Cranking Capacity you can properly fit in the holder.
Now: 2010 GLK350 4Matic Then: 2003 C320 4Matic, 2006 E320 CDI, 2000 E320, 1994 E320, 1991 190E, 1985 300D, 1983 300D
"Eagles may soar, but weasels don't get sucked into jet engines."