RE : Battery life =
Well it depends ;
I usually get 5 ~ 7 years out of every battery and I live in the Desert and use the AC .
As I said, back in the 1960's a 4 year battery meant you had a first generation SEARS DieHard or a nickel silver (? Exide brand ?) battery, neither was cheap .
Newer vehicles tend to have a larger parasitic drain when parked, my oldies (my 2001 Ranger stripper is my 'new' vehicle) have very little drain and, I always buy the largest size and CCA capacity battery that fits in the tray and still uses the hold down .
The # killer of lead-acid auto batteries is vibration ~ about 1/2 the vehicles I encounter, have no hold down atall, this is a very bad thing indeed .
The # 2 killer of auto batteries is over charging ~ 14.6 is great, anything more than that will overheat and damage the battery .
Likewise, chronic under charging (below 13.5 VDC when you're moving) is bad because it allows the battery to sulfate the plates, this fairly quickly shortens the life of the battery .
I tend to keep my vehicles in very sharp tune so not much cranking is necessary, this too greatly lengthens battery life .
In any engine using electronic fuel injection, touring the key to the "ON" position then waiting a couple seconds for the system to prime before cranking it over, results in *much* quicker tarts meaning less battery discharge , less starter / ring gear wear and so on .
It's all relevant, far too many cases as long as it starts eventually, the driver just hangs onto the key , grinding away and muttering 'start ya bastid' .
Once it fails to tart, then it gets a 'tune up' .
If you're one of those lucky few who has access to lots of batteries, be they old or new, choose the one you want by how much it weighs ~ the weight is a accurate indicator of how good quality the battery was when manufactured .
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