yo,
as the battery temperature declines, so does the minimum voltage. This is due to the effect of temperature on most chemical reactions. The battery reaction is slower as the electrolyte becomes cooler..." read more & see
TEMPERATURE-BATTY VOLATAGE CHART @
http://www.bbbind.com/BatteryLoadTest.pdf
and Walmart has some pretty good rated batteries for a price much lower than the same batty slapped w/a different label at parts stores.
Review, Walmart Everstart Maxx 65N; 850 CCA, 1000 CA (manufactured by Johnson Controls) Source: by miesk5 at Ford Bronco Zone Forums
I purchased this battery un NOV 07 at WAL MART
(battery is not listed in their web site)
It is mfg. by Johnson Controls & produces this EXACT SAME battery (CCA, etc.) for many auto makers and retailers under different product names such as:
Motorcraft Silver BXT-65-850; ~$100.00 to $120.00 Plus $104.95 + tax, etc. at your local friendly Ford dealer
Sears Die Hard Gold 33065 $105. +
Auto Zone (Duralast Gold)
Eveready
Everstart
Interstate Mega-Tron Plus $104.95 + tax, etc.
Toyota (TrueStart)
Mitsubishi (Diamond Car Care)
Mazda
Advance Auto (Autocraft Titanium)
Costco (Kirkland Signature)
Pep Boys (ProStart & Energizer)
btw, Johnson also mfg. Optima brand
WAL MART - excellent price $61.00 w/ 7% sales tax and free installation. The warranty is 3yr free and 108 month pro-rata
CCA: 875 amps @ 0 degree F/ CA = 1090 amps @ 32� F; Reserve capacity: 165 mins
compare CCA etc to Optima YellowTop
CCA = 500 amps @ 0 degree F/ CA = 625 amps at 32� F; Reserve capacity: 70 minutes
If you still have a prob, take it for a free load test at parts store
GL!