Three AGM, Gel Cell Battery Myths – UnderhoodService

Three AGM, Gel Cell Battery Myths

Chances are if the battery is not under the hood, it is an absorbent glass mat (AGM) or gel cell battery. These batteries pack a lot of power for their size and weight, which allows manufacturers to shave off a few pounds from the vehicle. That’s a big ­reason why they are being found more and more on late-model vehicles. Here are three AGM/gel cell myths.

Have you noticed more batteries are moving into the trunks and under the seats of some vehicles? Chances are if the battery is not under the hood, it is an absorbent glass mat (AGM) or gel cell battery. AGM eliminates acid spilling in an accident because it is sealed. They can be installed at odd angles. 
 

These batteries pack a lot of power for their size and weight, which allows manufacturers to shave off a few pounds from the vehicle. That’s a big ­reason why they are being found more and more on late-model vehicles. 
Here are three AGM/gel cell myths:
 
You can use your regular battery charger on AGM or gel cell batteries.
 
False. These batteries like to be charged slow and low. Many AGM/gel cell battery chargers 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. Overcharging can kill these batteries. Also, alternators are not chargers. Don’t rely on an alternator to do the work of a ­charger. If a battery is discharged to the point that it cannot start the vehicle, use a charger as soon as ­possible to make sure the battery gets fully charged.
AGMs and gel cells can be tested the same way as conventional batteries.
 
False. These types of batteries have lower internal resistance than flooded batteries. Older capacitance battery testers/analyzers may not be able to ­accurately read these batteries. Most new battery analyzers have a special mode for AGM/gel cell ­batteries. Old-school load testers might not provide conclusive results. 

AGM or gel cell battery replacement is the same as flooded battery replacement. 
 
True and False. While the installation of the ­battery may be the same for the two battery styles, some vehicles require an extra step to tell the vehicle that the battery has been replaced. Newer GM vehicles have a Battery Sensor Module on the negative ­battery cable. Ford has the Battery Monitoring System (BMS). Other manufacturers have similar systems. These systems require recalibration with a scan tool if the battery is replaced. If the system is not recalibrated, the alternator might overcharge the new battery and cause the battery to fail soon after replacement.

You May Also Like

Ford Adaptive Cruise Control Alignment Process

Follow these steps for proper horizontal alignment of the cruise control module radar sensor.

• 2010-2017 Taurus, Explorer, Edge, Flex, Fusion, MKS, MKX, MKT, MKZ

• 2015-2017 F150, Mustang, and MKC 

• 2017 Super Duty, Escape, and Continental

This is information on setting up and completion steps for proper horizontal alignment of the cruise control module (C-CM) radar sensor.

Chrysler’s Totally Integrated Power Module Simplifies Circuits

The symptoms of a failing TIPM can vary depending on the vehicle. Check out your options for this repair.

Trakmotive Tech Tip: Window Regulator Installation

Here are eight tips to make your next window regulator replacement easier.

Multi-Spark Ignition Systems

You may have seen the stories about plasma or laser ignition systems that promise to give new life to the internal combustion engine. But while these ignition systems have yet to make it to market the latest ignition innovation still uses a coil and spark plug.

VIDEO: How Modules Manage Alternator Power

Andrew Markel discusses power flow through the electrical system on a vehicle, and how the modules help provide the right amount of power to different components. Sponsored by Valeo.

Other Posts

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

Battery Management Means Knowing How It Ages

The battery may be fully charged, but you also need to measure how low the voltages go while the engine is cranking.

Power Window Regulator and Motor Service

Power windows are great as long as they roll up and down when commanded to do so.

EV Opportunities

You are gaining and retaining many service opportunities with Evs.