The one in my 2.0 TS is 500 CCA 90 RC
I noticed that if battery voltage is below about 11-12 volts the car will not start at all..... ie if car is left for a month with alarm on for example and the voltage drops but Battery still OK
In the colder climates, higher CCA ratings are more important; whereas, in a hot climate, a higher RC ratings are more important once the CCA rating has satisfied the OEM cranking amp requirement.
9.1) Cold Cranking Amps (CCA)
The most important consideration is sizing the battery's CCA rating to MEET OR EXCEED, depending on the climate, the car's OEM cranking requirement. [CCAs are the discharge load measured in amps that a fully charged battery at 0 degrees F (-17.8 degrees C) can deliver for 30 seconds and while maintaining the voltage above 7.2 volts. Batteries are sometimes advertised by their Cranking Performance Amps (CA) or Marine Cranking Amps (MCA) measured at 32 degrees F (0 degrees C) or Hot Cranking Amps (HCA) measured at 80 degrees F (26.7 degrees C), which are not the same as CCA. Do not be mislead by CA, MCA or HCA ratings. To convert CAs to CCAs, multiply the CAs by .8. To convert HCAs to CCAs, multiply HCAs by .69.]
In hot climates, buying batteries with double or triple the CCA ratings that exceed the OEM requirement is a WASTE of money. However, in colder climates the higher CCA rating the better, due to increased power required to crank a sluggish engine and the inefficiency of the cold battery. As batteries age, they are less capable of producing CCAs.
One of the major battery manufacturers, Exide, publishes the following table:
Available Power Temperature Power Required
From Battery degrees F To Crank Engine
100% 80 100%
65% 32 155%
40% 0 210%
25% -32 350%
[If more CCA capacity is required, two (or more) 12 volt batteries can be connected in parallel. Within a BCI group size, generally the battery with more CCA will have more plates because a larger surface area is required to produce the higher current.]
9.2) Reserve Capacity (RC)
The second most important consideration is the Reserve Capacity rating because of the effects of an increased parasitic (key off) load and in emergencies. [RC is the number of minutes a fully charged battery at 80 degrees F (26.7 degrees C) can be discharged at 25 amps until the voltage falls below 10.5 volts.] More RC is better in every case! In a hot climate, for example, if your car has a 360 OEM cranking amp requirement, then a 400 CCA rated battery with 120 minute RC with more electrolyte would be more desirable than one with 1000 CCA with 90 minutes of RC.
[If more RC is required, two six volt batteries can be connected in series or two (or more) 12 volt batteries can be connected in parallel. Within a BCI group size, generally the battery with larger RC will weigh more because it contains more lead.]