The Importance of Proper Charging
Both AGM (Absorbent Glass Mat) and GEL batteries are sealed, maintenance-free, and designed to deliver deep-cycle service. However, unlike the older flooded batteries, they must be charged with certain considerations. They may decrease their life span and lose capacity with time when overcharged, undercharged, or charged with an incorrect charger.
What is the good news? Properly charged, Fullriver AGM and GEL batteries can provide years of reliable service with minimal effort.
Charge it with the Right Charger
To charge a battery properly, the initial thing you need to do is to ensure that you have the right charger. A smart charger or microprocessor-controlled charger with AGM or GEL settings is required. Such chargers automatically vary the voltage and current according to the requirements of the battery, so mistakes like overcharging is far less likely to occur.
Never use trickle chargers or simple chargers that are not designed to work with sealed batteries in particular: they usually fail to appropriately taper the voltage and will ruin the battery in the long run.
Learn the Charging Phases
A good smart charger will generally undergo three or four charging steps:
Bulk Charge – This is the rapid charge stage and during which the charger supplies a constant current to charge the battery to approximately 80 percent of its capacity.
Absorption – The charger applies a fixed voltage as the current decreases, slowly bringing the battery to full.
Float – When the battery is fully charged, the charger drops down to a lower voltage to keep the battery charged without overcharging.
Equalization (GEL only when recommended) – Not all GEL batteries can handle a low-frequency equalization charge. It is always good to refer to the manufacturer’s guidelines before trying.
Right Voltage Charge
The charging profile of AGM and GEL batteries is slightly different:
AGM: The normal recommended charge voltage is 14.4–14.7V (on a 12V battery) during the bulk/absorption phase.
GEL: GEL batteries also tend to be charged at a lower voltage, usually 14.1–14.4V max, again depending on the battery.
Overcharging a GEL battery can cause the electrolyte to dry out, whereas undercharging an AGM battery might lead to partial charging and capacity loss.
Deep Discharges Should Be Avoided Where Possible
Although Fullriver batteries are built to withstand deep discharges, it will greatly increase the life of your battery if you can keep it above 80% state of charge at all times. Monitor charge levels with a battery monitor or voltage meter, particularly in off-grid or high-demand systems.
There is No Hurry – Slow and Steady Wins the Race
You may be tempted to give a fast charge when you are short of time, but AGM and GEL batteries prefer a constant and controlled charge. A properly sized charger will require several hours to fully charge a deeply discharged battery, and that is a good thing. Allowing a full charge cycle to take place will assist in avoiding sulfation and maintaining internal resistance low.
Charge It Stored and Float Maintain
When storing a battery over a season or more, be sure to fully charge it first. Then either disconnect it or leave it on a float charger. Storage of a battery in a discharged state, even over a few weeks, may result in permanent capacity loss.
Final Thoughts
Charging may sound like an easy task, but when properly done, it becomes one of the most effective means you have to make the best out of your Fullriver battery. Using the right charger, the right voltage settings, and some patience, your AGM or GEL battery will serve you better, last longer, and be there when you need it.
Need more answers to your particular configuration? You can count on our team, so don’t hesitate to contact us at info@fullriverbattery.com and we will do our best to optimize your system.
Further Reading
Powersport and Automotive Battery Charging: A Powerful Solution
AGM/GEL Battery Charger Selection
