Why are car batteries more prone to failure in the cold?

CCA – CCA is critical for cranking the engine over fast enough for it to start. It’s a scientifically tested, rated number of amps a battery can support for 30 seconds at a temperature of 17.8 degrees Celius until the battery voltage drops to unusable levels. A 12V battery with a rating of 600 CCA means the battery will provide 600 amps for 30 seconds at 0 degrees before the voltage falls to 7.20 V (six cells).

RC – RC helps to powers your vehicle’s electrical system if the alternator fails or the engine is turned off. It’s similar to the battery life bar you have on your phone for it’s battery and is rating of how many minutes the battery can supply ample power without falling below the minimum voltage needed to run your vehicle. In general for both CCA and RC, the higher the number the better. Batteries are sensitive items, and they do not like being discharged all the way down to it’s lower depths of RC, it will shorten the life of the battery even though your alternator will be doing it’s best to recharge it again once the engine starts.  If you drain the battery regularly, such as in a boat or 4wd that will use electrical load for fridges etc. then it is advisable to get a deep cycle battery, a different type of battery that reacts better to getting down into these deep dishcharge states.  

If you live in a cold climate, the CCA rating is an important consideration in choosing a battery as at those low cold morning temperatures the battery will be stressed harder. If you live in a high heat climate, you don’t need as much CCA. The final consideration is how much CCA for which engine – this generally follows a logical curve of how big your engine is and how much compression it has. So a Nissan 3.0 litre diesel engine will require a much larger battery than a Mitsubishi 1.5 litre petrol engine to get it turning over fast enough to run.

We electronically test your battery every service to determine it’s usuable life and it’s associated components that affect it’s life – documenting the lowest that voltage drops to when cranking the starter and what voltage the alternator is charging the battery at – the starter and alternator serviceability have a large influence on battery life, as a weak starter or corroded cable to the starter, requiring the battery to work harder than normal, will certainly shorten the batteries life. 

Generally we recommend a new battery when it’s CCA rating has dropped below a certain percentage of it’s maximum value and voltage drops to below 10 volts while cranking the vehicle over – providing the starter and alternator are in good condition. Several variables are taking into account for this, such as – Are we coming into winter? How many electrical accessories is the customer likely to run with the engine off?

If a battery is found to be weak during our computerised test done at every vehicle service, we stock a large range of top quality batteries covering a range of vehicles, so we can take care of Browns Plains battery sales for the majority of vehicles. Car sounding a little sluggish when cranking? Drop in for a free computerised battery test and we will give you a printed out health state of that battery, starter and alternator system. 

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