Charging Your AGM Battery
Here are a couple of things to keep in mind when maintaining your Absorbent Glass Mat (AGM) battery, including an OPTIMA® battery.
Many newer battery chargers, like the OPTIMA Chargers Digital 1200 12V Performance Battery Charger and Maintainer, have microprocessors that collect information from the battery and adjust the current and voltage accordingly. Some have different settings for charging flooded, gel and AGM batteries.
All lead-acid batteries can experience sulfation—the formation of lead sulfate crystals upon discharge. Look for a charger with a desulfation mode to help condition your battery and keep it performing at its best.
Low and slow is best. A low amp charger (one to 12 amps) is generally the best choice for charging any lead-acid battery. It's quicker to charge at higher amperage, but it also can generate a lot of heat, which reduces the life of a battery, just like the heat of summer.
Alternators are NOT chargers. Don't rely on your alternator to do the work of a charger. If your battery is discharged to the point where it cannot start your vehicle, use a charger as soon as possible to make sure your battery gets fully charged.
An alternator is meant to maintain a battery, not charge it.
Batteries eventually die. Batteries are a consumable product. No battery will last forever. The goal is to consistently maintain your battery to get the most life out of it.
Different chargers. Different capabilities. Under normal conditions most 12-volt automatic battery chargers will work on an AGM battery. Many newer battery chargers have settings specifically for AGM batteries; some even have separate settings for OPTIMA REDTOP and YELLOWTOP batteries, like the OPTIMA Chargers Digital 1200 12V Performance Battery Charger and Maintainer.
AGM and gel technology differ. Remember that the technology of an AGM battery is not the same as a gel battery, which has its own charging requirements. If your charger offers different modes, select the correct one for your battery. If you use the gel setting to charge an AGM battery, it won't fully charge and, over time, it could actually damage your AGM battery.
Under normal starting conditions, an OPTIMA battery should never experience at rest voltages below 12. Most 12-volt chargers and alternators have no problem recharging an OPTIMA if it has an at rest voltage of 10.5 or greater.
The magic threshold – 10.5 volts. The charging scenario for a deeply discharged AGM battery, one that's dipped below 10.5 volts, may be slightly different. The OPTIMA Digital 1200 can recover batteries that have been discharged as low as 1.25 volts. For other charger tips for recovering a deeply discharged AGM battery can be found in OPTIMA's tech tip, How to Resuscitate a Deeply Discharged AGM Battery.
How long do I need to charge my OPTIMA battery?
How the rated capacity of a battery will help determine how long it will take to charge.