Vehicle Maintenance 101: Batteries

All of us have, at one time or another, had experience with a dead car battery. They almost never seem to fail at a convenient time. When they do, fail, however, it can sometimes be a bit daunting to find a replacement. There are several things to take into consideration when buying a battery: Cold Cranking amps, Amp-Hours, Group number, Battery type, and terminal location.
So to star things off, This is a Battery. This particular example fits the 2011 - 2015 Hyundai Sonata and 2007 - 2013 Hyundai Santa Fe, as well as a few other models. As you can see, this is a Lead-Acid Battery, as indicated by the 2 caps on top. This is a Group 124 battery, which indicates it's exterior dimensions. This is also known as a Top-Post Battery, as it's Negative (-) and Positive (+) Terminals are on top (the 2 shiny bits) rather than on the side.

As the caps indicate, the Sulfuric Acid in these batteries is incredibly toxic, corrosive and caustic. Do take proper care when handling old batteries. Most Lead-Acid batteries used in cars use 6 individual cells inside the battery that produce 2.1 volts apiece, making a total voltage output of 12.6 volts.

The information labels show most of the information needed to find a replacement. First off, we see the part number "124R 00275-16001". The 124R means it's a group 124 battery, though it's terminals are reversed from normal group 124 batteries, as indicated by the "R". The 00275-16001 is simply the part number assigns to this particular battery.

The next line, "CCA 700 / RC 120", indicate's its power output. Cold Cranking Amps, or CCA, refers to the batteries ability to deliver current, in Amps, at zero degrees Fahrenheit (-18C). The higher the number, the more effective the battery will be at starting the engine in cold weather. Naturally, the bigger the engine, and the higher the compression, the more CCA's you'll need to start the engine.

Reserve Capacity Minutes, or "RC", refers to the battery's ability to sustain an adequate amperage output before the voltage drops from 12.6 volts to below 10.5 volts. This one states it can crank for 120 minutes at full charge before it is too dead.

The bottom of the label is an indicator of sales date used for warranty replacement purposes.

Most batteries tend to lose charge over time. Most battery suppliers rotate their stock. The date code sticker indicates the date of manufacture. Usually, retailers rotate their stock every 3 months. This is also a good indicator of battery age.

The most important thing to know about batteries, other than their rather toxic nature, is that hooking up a battery backwards can result in very expensive repairs. You could potentially back feed voltage into a computer and cause a short circuit.

Finally, when replacing your battery, most suppliers charge you for the core, which is refunded  when you bring the old unit back.. This is the easiest and best way to dispose of batteries.

Some cars use an Absorbed Glass Mat, or AGM battery. Also known as a Spill-Proof, Gel Cell or Maintenance-Free Battery, these tend to be quite expensive (nearly double that of a Lead-Acid type), but can be mounted in any orientation...even upside down. Shown above is an Optima-brand battery, the most common aftermarket AGM brand. (photo credit: Google images)

Some high-performance cars might have a lightweight Lithium-Ion battery like this example from Braille Batteries. These, while more expensive than even the AGM type, are super lightweight and compact, while having the same output and recharge-ability of a standard lead-acid type. (photo credit)

So, if you need to replace your battery, remember to look at your old battery to get the specs. If there are none, which is common with Original Equipment batteries, your local auto parts store usually has a catalog you can use to find what group number your car calls for.

When it comes to making the purchase, look at the warranty on the battery, as well as the brands. Most automotive batteries are manufactured by one of 4 or 5 larger manufacturers, including Johnson Controls, Deka and Interstate. Hyundai's batteries are all made by Interstate. I haven't done enough research to know if any one brand is better or worse than any others. But, it's always a safe bet to get a battery made by the same manufacturer as the factory battery.

Anyway, I hope this was a help. Do check back for more awesome cars, event coverage and, hopefully, car art and build coverage. And stay tuned. I'm working on a new post covering a special exhibit at the Gilmore Car Museum.

-Phil