Battery Health
How Long Does It Take to Charge an AGM Battery?
How long to charge an AGM battery depends on its size, depth of discharge and charger output. See realistic amp-hour math and when to stop charging.
A battery that fits your vehicle and starts on cold mornings
We sort car, truck and SUV batteries by group size, cranking power and type, so you can match the one under your hood. Pick a group size, look up your vehicle or check whether your old battery is really on its way out.
Latest guides
Group SizesWhat Is a Group 31 AGM Battery?
A Group 31 AGM battery is a large 12V absorbed glass-mat battery built for high cranking power and deep-cycle use. Learn its size and typical uses.
Battery HealthHow Do You Identify an AGM Battery?
How do you identify an AGM battery? Check the case label, look for AGM or VRLA wording, and read the size code to confirm the type before you buy a replacement.
Types and BrandsIs an AGM Battery a Lithium Battery?
No, an AGM battery is not a lithium battery. Learn how AGM lead-acid chemistry differs from lithium, what each one needs, and how to tell them apart.
Battery HealthCan You Load Test an AGM Battery?
Yes, you can load test an AGM battery. Learn what a load test reveals about its condition, how to run one safely, and when to replace it.
Types and BrandsIs an AGM Battery a Gel Battery?
Is an AGM battery a gel battery? No. AGM holds acid in glass mats and gel suspends it in silica, so charging and fit differ between the two.
- Battery Health
Can You Jump-Start an AGM Battery?
Yes, you can jump start an AGM battery when it's low. Learn safe cable order, voltage checks and why a deep discharge needs a charger.
Types and BrandsIs a Marine Battery an AGM Battery?
Is a marine battery an AGM battery? Not always. Marine batteries come in flooded, AGM and gel builds, and AGM suits many boats and RVs.
Battery HealthWill a Car Alternator Charge an AGM Battery?
Yes, a car alternator will charge an AGM battery when the charging voltage is right. Learn what AGM needs, how to check it and when it falls short.