Automotive Battery Information


Battery life is influenced by type of driving, how long the battery spends at below full charge, how often heavily discharged, under-hood heat and of course quality of the battery.

Cause of low battery charge are; short trip driving cycles, long periods of not driving or charging system problems.

Battery Ratings

Cold Cranking Amps (CCA)
Indicates how many amps a battery can deliver for 30 seconds and maintain at least 7.2 volts at 32 F.

Cranking Amps (CA)
Similar to CCA; Cranking amps is a measure of the number of amperes a lead acid battery at 32 degrees F can deliver for 30 seconds and maintain at least 1.2 volts per cell. (CA ratings are more commonly used in climates where temperatures rarely drop to 0F.)

Reserve Capacity (RC)
Reserve capacity is the time in minutes that a new, fully charged battery will deliver 25 amperes at 80 degrees F and maintain a terminal voltage equal to, or greater than, 1.75 volts per cell.
Reserve Capacity requires higher quality cell materials which means cheaper batteries have less.

What it Means
A higher CCA will give you more raw starting power and a high RC will help keep a battery going longer when an alternator fails or something is left on such as the headlights. Some batteries will have a high CCA but a small RC, which can leave you stranded if you leave your door open for a while, let the car sit for several days at a time or do a lot of short trip driving.
Never use a battery with a lower capacity rating than is recommended by the manufacturer, not only will it fail early, some very cold morning it may leave you sitting.
A 4 year battery may be at 50% in 2 years, always buy a five or six year battery.

Why they go Bad
Heat and vibration are the biggest battery killers, heat causes a battery's positive plate grids to corrode more rapidly and can cause the battery plates to warp and short out. A missing or improperly installed battery hold-down will cause excessive vibration. Many other factors can also cause battery failure, such as: corroded cables and terminals, sulfating, alternator/regulator malfunction, and electric draws. Anytime a battery is discharged (goes dead) it shortens the battery's life.

Jump Starting

When jump starting a car take extreme care to make sure you jump positive to positive and negative to negative. Don't assume because they're on the same side of the battery it is correct, batteries can come with the positive terminal on either side. Don't always assume the positive cable is going to be red. Hooking them up wrong can cause expensive electrical damage.
It is a very good idea to shield your eyes and face from the battery when making connections and follow these steps:

  1. Connect the positive [+] cable to positive post of discharged battery.
  2. Connect other end of the same cable to same marked post (positive) of starting vehicle battery.
  3. Connect second cable (negative [-] ) to other post of booster battery.
  4. Make final connection on engine block of stalled vehicle away from battery.
  5. Start vehicle and remove cables in reverse order.

Sometimes on newer vehicles there is no place to get on the block or brackets and it may require hooking final cable to battery also.

If a battery is discharged rapidly, it can be recharged rapidly.
If it's discharged slowly, it should be recharged slowly on a trickle charger. (This could take 8 - 10 hours on a fully discharged battery)
Note: Overcharging a battery will damage the internal plates and shorten battery life.

Batteries are 99% recyclable and are filled with lead and acid. Please recycle your batteries!

Batteries and Winter Driving

As daylight gets shorter, short trip driving with lights, defrosters and wipers running can slowly discharge a battery because the alternator doesn't have time to make up for the energy used to start the vehicle and run all the accessories. Alternator output is lower at low speed driving than when you are out on the highway. Each day the battery may become another 1 or 2% discharged leading to a problem within a few of weeks. Running batteries low on charge causes shortened battery life and can cause older batteries to fail.

One way to prevent this is to take the car out once a week for a longer drive.

Also, a low or marginally bad battery can continue to start a car for months, but during starting the voltages can be so low that we often see electronic issues such as performance problems caused by the computer being confused by the low voltages during starting.

If your battery does get discharged due to short trip driving or leaving the lights on it's important to know that it can take 4 - 6 hours to properly charge a fully discharged battery.

If your battery gets discharged, don't expect the alternator to do the job, especially in the winter. To begin with, unless you're going on a long trip you won't fully charge the battery, leading to possibly more problems or early battery failure. Alternators are not designed to charge a fully discharged battery. Doing so can shorten its life or cause it to fail.

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