The Ultimate Buyer’s Guide to Consumer Car Batteries

Understanding your car battery is a topic I expect most practical people, including doctors to know about. It doesn’t matter if you’re some hotshot neurosurgeon in New York City or dermatologist in Abilene, TX, you will be considered a smarter person if you know something about your car battery. Period.

Since this is a website that discussed finance, you’d better believe that you can save a bit of money over the years by understanding the basics of your car. You’re not going to become a multi-millionaire by saving on your car battery, but there is also no reason why you should squander your earnings on one of the easiest parts of a car to understand.


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The fundamentals of car batteries for everyone 

If you know nothing about car maintenance or if you don’t care about car maintenance, then you should just read this section. The bottom line is that all batteries have a limited lifespan.  Unless you lease your vehicle, you will need to replace your car battery at some point during the life of the car. It could be one year. It could be five years. We just don’t know. Most car batteries will probably last at least three years.

Here are some conditions that will shorten the life of your battery:

  • Cold weather. If you live in the Northeast or in an environment that is cold most of the year, your car battery will not last as long as it would in warmer weather simply because batteries lose voltage in cold weather. Your battery also loses voltage as it ages, so your battery will be more susceptible to failure
  • Infrequent driving. This usually isn’t a problem in America—we drive too much. However, batteries naturally self-discharge over time. Every time you run your vehicle, the alternator will recharge the battery. While it is becoming more uncommon to permanently discharge a battery completely as technologies improve, your battery might not recharge if you allow it to discharge completely. The battery can be reconditioned back to life, but that is not anything I would expect common users to have to deal with.

How will I know if my car battery needs to be replaced?

  • If your car doesn’t start, the battery is the most common cause.
  • If your car has difficulty starting, the most common cause is the battery.
  • If your car is beginning to have more difficulty starting in cold weather, your battery might be getting weak.

If you take your car to the local dealership (or if the dealership picks your car up from your house for routine maintenance), rest assumed that they will let you know when you need to replace the battery. Otherwise, an auto parts store such as Autozone will test your battery at no charge.

If your car battery needs to be replaced, and you aren’t interested in price shopping or self-installation, go to Walmart, Sam’s Club, or Advanced Auto Parts. They will install the battery for you, and you’ve effectively saved at least $100.

You’re welcome.


Car battery factoids for intermediate folks.

Congratulations! You’ve decided to care about your car beyond taking the car to get serviced by the dealership. You’ve already taken the step to saving money on your vehicle, which is more than what most doctors will understand.

In the interest of avoid being stranded in the middle of nowhere due to a dead car battery, everyone should know how to jumpstart their car battery. Even if your car battery should have been junked years ago, you can still start your car’s [gas] engine if you can get enough juice through the car battery.

Better yet, get a car battery jumpstarter.

Keep one of these in your car, and you won’t ever have to call AAA or wait for a friendly stranger to help.  Even if your car battery is dead beyond repair, you can get your car back home with a battery starter.

In practice, a 12v battery probably only has a few useful hours of juice. However, as mentioned above, the battery will last several years. The reason is that the alternator in your vehicle kicks on and recharges the battery as you drive. If your alternator goes bad, your battery will also die.  Batteries ultimately stop working mainly due to sulfation of the electrodes and loss of water.


Real-world examples of car battery pricing.

I priced out a standard 35N lead-acid battery with approximately 640 amps of cold cranking current for my 2006 Subaru Impreza. The local dealer quoted me a rate of $350 for the replacement job, with a standard warranty of 3 years.  By taking my vehicle to a local auto parts store, I’d save approximately $150. If I wanted to do the replacement myself, I’d probably save another $30.

The savings are even more dramatic if you drive a higher-end vehicle. The local Mercedes dealership quoted me a battery replacement fee of $650 for a 2014 SL AMG 63 (free car wash included with servicing). The equivalent battery costs around $160 elsewhere! The Hummer dealership charges $995 to replace an otherwise $160 battery on an H2 (free car wash also included). Sounds like an awfully expensive car wash to me.


How much financial gain will you truly get from understanding car batteries?

Any complex goal can be broken down into a series of discrete steps. Each individual step isn’t going to solve all of your problems, but will help you achieve your ultimate goal.  Likewise, saving money on a car battery alone isn’t the solution to reach financial freedom. However, it is a skill that builds upon your financial armamentarium.

You might also like: How to replace the cabin air filter of a Mazda 3.

Prudent selection of a car battery will probably save you $200 every three years. This is post-tax dollars. For many high-income folks this can mean $400 of pretax money. That’s like doing one extra appendectomy!

This isn’t big money, but practicing these good habits will help you save on other expense in the long term.

What examples have you taken in saving money?

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