With all of the electrical demands placed on today’s cars (start-stop technology, in-vehicle entertainment, etc.) picking the right replacement battery is crucial. For us old car guys, we equated battery power with CCA (cold cranking amps). Not so anymore.
Key Battery Types: Standard Flooded vs. AGM
The car batteries we are most familiar with are known as Flooded Lead-Acid batteries. These still have application in today’s cars, but it is important to know when to use them versus the more advanced AGM.
Flooded Lead-Acid Batteries
The standard flooded battery is the most common type of auto battery. It provides power to reliably start your vehicle and provide power for standard vehicle electrical accessory loads.
A standard flooded battery is designed to supply power to the starter and ignition system to start the engine. It also supplies extra power when the vehicle’s electrical load exceeds the supply from the charging system. It provides power to electrical systems such as the clock and computer systems when the vehicle isn’t running. `
This is the type of battery we are used to buying, and still has application for a lot of today’s cars.
Standard Flooded Battery Benefits
- Reliable starting power
- Basic charge acceptance
- Suitable for all climates
- Lowest-cost option
Standard Flooded Battery Disadvantages
- Limited ability to power large accessory loads
- Limited cycling capability
- Shorter life compared to other technologies
AGM Battery Technology
AGM or Absorbent Glass Mat is an advanced lead-acid battery that provides superior power to support the higher electrical demands of today’s vehicles and start-stop and hybrid applications.
AGM batteries are extremely resistant to vibration, are totally sealed, nonspillable and maintenance-free. AGM offers better cycling performance, minimal gassing and acid leakage when compared with conventional lead-acid batteries.
The end result of all of the features of AGM technology is superior life performance.
Not all cars require an AGM battery, but they can be used on them if desired.
AGM Battery Benefits
- Up to 2x longer life than standard flooded batteries
- Designed for harsh climates and demanding conditions
- Handles high electrical loads
- Quickly recharges and extends cycle life
- Ideal for start-stop applications
- Vibration resistance
- Nonspillable and maintenance-free
- Greater mounting flexibility
AGM Battery Disadvantages
- Higher initial investment
When it is time to buy…
Check your owner’s manual (you know, that thick book in your glove compartment that is still wrapped in plastic?) to see what your vehicle manufacturer recommends. Heck, take it out and check all of the good info it contains!
I recently replaced the battery on my wife’s 2014 MINI Countryman. I was shocked to discover that I also needed to get the battery “coded” after the new one was installed. It seems the ECU (vehicle’s on-board computer) had to be told a new battery was installed so it would not overcharge it (the ECU compensates the charge based on battery life). So, check the owner’s manual and listen to your dealer or local parts store (wherever you choose to buy your battery).
While they are not a sponsor of this website (actually, no one is yet), I am a big fan of my local AutoZone for batteries and parts too heavy to ship, and www.RockAuto.com is my go-to for parts that can wait 2-3 days for shipping. More on that in another article!
Questions? Post them below or on the “Ask the Nanny” page.