How to Charge an AGM Battery

Updated on Aug 16, 2023

Written by
 RealTruck Expert Team

AGM batteries have a slew of advantages over flooded automotive batteries including greater durability, reliability, and resistance to premature failure due to extreme temperatures. When charging an AGM battery, it’s important to follow a few simple rules to ensure your battery continues to work hard for you and your vehicle. In this article, we’ll explain the rules for recharging a discharged AGM battery.

Don't exceed ten amps when charging your AGM battery.

## Ten Amps or Less If your AGM battery has been discharged beyond your alternator’s ability to maintain it, the battery should be recharged as soon as possible. Simply attach the battery to your charger and make sure it doesn’t exceed 10 amps at 13.8 to 15 volts during the recharging process. The process may take several hours, even up to 12 hours on deeply discharged batteries. If your battery charger has specific settings for AGM batteries, make sure you utilize them to optimize the recharging process. By keeping the charging amps at 10 or less, you’ll avoid overheating the battery and prolong the battery’s overall lifespan.

## What Not To Do Keep in mind that an AGM battery isn’t the same thing as a gel cell battery. An AGM battery has no free-floating electrolytes while a gel cell suspends the electrolyte in a gel state. For this reason, you should not use the gel cell or spiral cell settings on your battery charger when recharging an AGM battery. While batteries can be recharged more quickly by surpassing the recommended 10-amp limit, this will cause the battery to heat up, which can shorten its overall life. If your battery is registering 10.5 volts or less, a standard battery charger may not be able to return the battery to operating condition. A top-of-the-line charger such as the Optima Digital 1200 Battery Charger & Maintainer may be required in this situation.

Recommended Battery Chargers

CTEK Multi US 7002

This universal charger takes a lot of the guesswork out of recharging your lead-acid battery. It’s capable of reading a battery and, by using its unique eight-step charging method, restoring a viable battery to operating condition while prolonging its service life. The CTEK Multi US 7002 is rated for use in extreme cold and intense heat. This charger is safe to use even if the battery is still connected to your vehicle and can be used to back up important settings on your vehicle without losing them while the battery charges. Maximum charging amps: seven.

Optima Digital 400 Battery Charger & Maintainer

From the same company that produces the popular Redtop and Yellowtop AGM batteries, the Optima Digital 400 is a compact, powerful battery charger. It features an easy-to-read LCD display, a dual-purpose stand, and multi-stage charging modes to maximize battery life. Simply attach your battery, choose your battery type using the single-touch interface, and let the Digital 400 do its job. Maximum charging amps: four.

Optima Digital 1200 Battery Charger & Maintainer

Designed to recharge even the most deeply discharged batteries, the Optima Digital 1200 Battery Charger & Maintainer is an uncompromising battery charger with tons of beneficial features. This charger has one of the most intuitive user interfaces available and a display for fill rate, fault messages, and charging status. It also includes a USB charging port, making it ideal for modern homes and garages. Maximum charging amps: twelve.

If you have questions about batteries or battery chargers, chat or call our product experts.

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