When it’s time to buy a new battery for your Honda Civic, make sure you get the best battery for your vehicle. Group size and chemical makeup are two things you want to get right. The proper group size ensures the battery fits, and chemical makeup determines the battery’s longevity.
What is the battery group size for the 2020 Honda Civic?
The 2020 Honda Civic uses a Group Size 51R battery. The Group Size 51R battery is a top-post battery. It is 9.3 inches long by 5.1 inches wide by 8.9 inches high.
Once you find the size battery you need, you also have several other choices to make, such as the battery’s chemistry and the brand you want to use. Continue reading this Vehicle History article to learn more about batteries for the Honda Civic.
Battery Group Sizes Explained
The battery group defines the battery’s physical dimensions and the location of the terminals. While a battery from another group might fit in your vehicle, it might not be the correct battery for your vehicle due to the location of the terminals or the chemical makeup of the battery.
Lead-Acid, Lithium-Ion, or SLI?
The 2020 Honda Civic uses a Group Size 51R 410 cold-cranking amp battery to start the vehicle and run the accessories.
Even if your Honda came with a lead-acid battery, you should change it to an absorbent glass mat (AGM) battery, especially if the trim level you own uses stop / start technology, if you have a lot of accessories, especially add-on accessories, or if you live in a cold climate.
Lead-acid batteries are still in use today. A lead-acid battery is flooded and sealed or is valve regulated. If you were to take a battery apart, which is definitely not a good idea, the two would look the same inside.
The flooded and sealed version could leak, so it has to be installed upright. It also needs ventilation because of the gasses it creates. Finally, the electrolytes need to be maintained.
Valve regulated (VRLA) batteries are gel or absorbed glass mat (AGM). A gel battery uses a thickening agent to convert the electrolyte from a liquid to a gel. An AGM battery uses a glass matrix to contain the electrolyte in its liquid form.
Most vehicles use “shallow cycle” batteries for start, light, ignition (SLI). An SLI battery must have the ability to deliver high power pulses for a short time, such as what you might use to start the vehicle.
Lithium-ion batteries use a charged lithium-ion that goes back and forth between the anode and cathode while the battery is discharging and charging. How the battery is packaged, plus the chemistry differences between the electrolyte, the cathode, and the anode are what makes the battery work.
This chemistry is different from manufacturer to manufacturer and could be cobalt, NCA, manganese, NCM, and LFP. Most lithium-ion anodes are titanium and silicon-based materials. Those materials account for the higher cost of a battery.
OEM vs. Aftermarket: What’s the Difference?
The manufacturer recommends using an absorbent glass mat (AGM) battery for the Honda Civic, especially if you are in an area of the country with extreme climate conditions. An AGM battery resists corrosion from heat and has better electrical performance for those who have a lot of accessories.
Because the AGM battery better resists cold, it lasts longer in colder climates and is less likely to leave you stranded on a cold day. An AGM battery is also recommended for vehicles with Start / Stop technology.
If you use an aftermarket battery, it might not be an AGM battery. You can use a flooded battery as an option to the AGM battery, though it won’t perform as well as the AGM battery, especially in colder weather or if you have a lot of accessories.
Tips for Replacing a Honda Civic Battery
The battery for the Honda Civic is usually right in front of the engine bay, where it’s easy to get to. Always remove the negative battery cable first. Tuck it aside, ensuring that it is not touching anything metal.
Remove the hold-down bracket, then remove the positive battery cable. Lift the battery out and set it aside. Clean the terminals on the battery cables with a battery terminal brush.
Insert the new battery. Reinstall the battery hold-down bracket, then the positive cable. Reinstall the negative battery cable. Spray battery terminal protector over the terminals and any exposed metal on the battery cable ends and terminals.
How to Tell if a Honda Civic Battery is Dead
Batteries put out voltage and amperage. The battery could have plenty of voltage, but if it doesn’t have enough amperage, the Civic won’t start.
Before starting the vehicle, check the voltage with a voltmeter. If the voltage is low, have someone start the Civic while you watch the voltmeter. If the voltage drops below 10, the battery could be low on amperage.
Jump the vehicle. With it running, check the voltage again. If the voltage is below 12 volts and does not rise – or it continues to drop – the alternator is not charging.
If the voltage is below 12 volts, but rises the longer the Civic runs, you can try charging the battery, but it’s better to replace it. It may not hold a charge for very long, especially if the battery is over three years old.
If You Do Go Aftermarket, Here’s What We Suggest
We recommend using the Group 51R Diehard Platinum AGM battery with 435 cold cranking amps as an alternative to an OEM battery. The AGM battery is less likely to let you down during the winter months, charges faster, and is great if you have stop / start technology and a lot of added-on accessories.
