Now granted, I might be a bit confused, but I was under the assumption that while a motor was running, the power for the car was provided by the alternator , and the battery acted like a capacitor to "smooth" out the electricity and make it safe for delicate components.
Agreed that batteries are fickle, but one would stand to reason that lessening the resistance from the alternator, to the battery, to the car would mean better power transfer, and less loss. Also SHOULD cause the battery to discharge less, since more of the alternator power would be getting through.
That being said, when I replace my battery (which happens about every 5 years) I buy the BIGGEST battery I can get, and get at least a 5 to 7 year warranty. Its worth it to spend 50-80 more dollars to save myself 200 later.
I've got the parts for the "big 3" on order, and plan to do it soon, if nothing else than to just make sure all my connections are good, and eliminate any power sapping corrosion.
I don't, however, know what the "big 5" is..