Automotive Batteries – Why It’s Important to Buy the Right One

Over the years, there have been many changes in automotive batteries. Many new innovations have been tried; some advances have worked, while others have not.

The single biggest change in the automotive world is the introduction of “stop-start” systems, now installed in vehicles to improve fuel economy. When you come to a stop, the vehicle shuts off until you release the brake, then restarts.

Personally, I’m not a fan of this system. It causes additional wear on engine components, even though some vehicles have electric pumps to circulate water and, in some cases, oil. The problem lies in the frequent stops and starts, which make choosing the right battery crucial.

The AGM battery is specifically designed for this purpose. It has a higher voltage and can sustain numerous starts, with a charging system finely tuned for it. Even vehicles with regenerative braking systems are optimized for these batteries. So why don’t automotive retailers like NAPA, Advance Auto, O’Reilly’s, and AutoZone share this information? Is it about profits? Who knows, but choosing the wrong battery will cause issues in the long run.

Yes, all of these stores carry AGM batteries, either as their private brand or, like NAPA, only the Optima line. However, they also sell Lead Acid, Advanced Flooded, or Enhanced Flooded batteries, which use older technology with some improvements. While advanced or enhanced flooded batteries are marketed to handle “stop-start” systems, they are lower in quality. They are still standard batteries with minor enhancements, running at a lower voltage and unable to handle frequent restarts. The charging systems in newer vehicles are not optimized for these batteries, but many auto parts salespeople are untrained and often sell the cheapest option, inviting trouble.

For example, when I went to NAPA to purchase a battery for my wife’s Subaru, I found they no longer offered the 84-month Legend Premium AGM battery. Instead, they suggested a Triple A (AAA) battery as a replacement, but it was an enhanced flooded battery, not of the same quality as an AGM. When I called AutoZone and O’Reilly’s for comparison, the associates gave me different prices for various batteries but none mentioned that the Subaru required an AGM battery. Even NAPA associates failed to ask the simple question, “Does your vehicle have a stop-start system?”

AGM batteries are more expensive, but there’s a reason. They are designed by the OEM manufacturer for vehicles with stop-start systems, and the charging systems are optimized for this type of battery. Installing a flooded battery where an AGM is required won’t damage your vehicle, but the charging system isn’t optimized for it, and the vehicle’s regenerative braking won’t properly charge the battery. Advanced and enhanced flooded batteries can’t handle the heavy load of frequent stop-starts and don’t perform well in extreme temperatures and even though the manufactures claim they work with no issues it still isn’t the correct battery for. your vehicle according to the OEM.

When buying a battery, don’t blindly trust auto parts employees. Some are knowledgeable, but many are unaware of these issues. Simply replacing your battery with one of the same size isn’t enough anymore. For instance, Jeep owners will quickly realize that using any battery other than an AGM triggers a warning light: “start-stop system disabled,” because the battery voltage is too low. While other vehicles may not display this warning, rest assured, your vehicle won’t function as it should.

If this blog has confused you, I recommend going back to the dealership and paying a higher price for the right battery. At least the dealer will sell you the correct one. If you can remember the term “AGM battery” for newer vehicles, you’ll be making the right choice. The label on the front of the battery will confirm this. Don’t be fooled by cheaper prices or uninformed parts employees.