The short answer is: You can't trust anybody.
I just logged onto my Consumer Reports Online account (highly
recommended over the paper subscription), and the ratings show no clear
rule that can be followed. Some that ranked best in one size group
ranked lowest in another.
I'll violate copyright law and share a few of the results here. Don't
Feel free to email me directly and ask for particular details if you'd
Models with a (North) designation indicate an emphasis on Cold Cranking
Amps, and (South) indicates added heat resistance.
Always make sure you are buying the newest sample available at the
store, and certainly no more than 6 months old.
The main finding is that there are tradeoffs for all of the samples.
Some are better at cold weather. Some are better at providing reserve
power (lights left on, etc). Others are better in warm weather. There
are some that are good all the way around (like the Duralast (AutoZone)
Group Size 65:
Duralast (AutoZone) 65-D
DieHard (Sears) Gold 33165 (South)
Interstate Mega-Tron MT-65
Napa Legend 7565
Group Size 75:
Interstate Mega-Tron MT-75
DieHard (Sears) Gold 33175 (South)
Duralast (AutoZone) 75-D
Pro Start (Pep Boys) Premium 75-650
Kirkland (Costco) Signature 12841
Group Size 24:
Advance Autocraft (Advance Auto) Silver 24-5
DieHard (Sears) WeatherHandler 30024 (North)
Napa Legend 7524
Interstate Mega-Tron MT-24
Group Size 34/78:
Kirkland (Costco) Signature 12860 (North)
Advance Autocraft (Advance Auto) Titanium 34/78-4
ACDelco Professional 78DT-6YR
Exide Nascar Select 78DT-84N
All of that data aside, I can't recommend enough (especially for
cars/batteries left sitting for longer periods) an electronic pulse
charger like those you'd find at http://www.pulsetech.com/. I'm not
trying to sound like a shill, but these are indeed based on real, proven
science. You won't be replacing a battery because it won't hold a charge
(because the plates have sulfated enough to render them unable to react.
The age of the batteries in my dad's twin-engine Cessna 310R is around 8
years at this point, and they show *no* degradation at all. He leaves a
24V version of their pulse charger connected while the plane is parked
in his T-hangar.
There are versions designed to be installed permanently, using the
battery to provide power for the pulse-conditioning - and it won't run
down the battery, even if left there for a year without a charge.
Oh, and I'm sure Aric Datesman (who introduced me to the list) will have
questions for you all soon, as he's driving his new car (1966 Volvo 122)
from Jacksonville, FL back to Norristown, PA this weekend. Thus far,
it's miswired headlights (reversed high/low beam on one side) and brake
lights that pop fuses (and thus take out the heat). He'll be staying
here Saturday night - we'll see what we can figure out Saturday
afternoon here in Vienna.
Glad I can contribute something more car-related (it's typically
computer networking and cordless phones, since I have no LBC to
Peter Murray (N3IXY)