An AGM battery is charged with a battery charger.
The most common battery chargers are 3-stage battery chargers, trickle chargers, alternators and DC buffer power supplies.
In the way of charging, a distinction is made between standby and cyclic use.
Cyclic use means that the battery is discharged and recharged regularly, for example in an electric wheelchair or golf trolley.
Standby use means that the battery is called on infrequently.
For example, a battery in a UPS.
It is called upon only when the power fails.
Charging a standby lead-acid battery
For standby use, an AGM or Gel battery should be charged at a constant voltage between 2.25V and 2.3V per cell.
For a 12V battery, that means a voltage between 13.5V and 13.8V.
This can be done using a 3-stage trickle charger or a DC power supply.
When there is a continuous load connected to the battery and charger, it is best to use a DC power supply to charge.
The current the battery charger must be able to supply is between 10% and 25% of the battery’s capacity.
That means that a Cellpower CP 12-12 with a capacity of 12Ah should be charged with a battery charger that can deliver between 1.2A and 3A.
Charging a cyclic lead acid battery
An AGM battery used cyclically should be charged at a constant voltage between 2.4V and 2.48V per cell.
For a 12V battery that means a voltage between 14.4V and 14.9V.
A Gel battery should be charged at a maximum of 2.4V per cell otherwise permanent damage to the battery will occur.
For optimum service life, it is important that when the battery is full, the battery charger switches to a maintenance charge with a voltage between 2.25V and 2.3V per cell.
This can be done using a 3 stage battery charger.
It will first charge at a high voltage and when the battery is full switch to a maintenance charge.
An alternator can also be used for this, but never without a charge controller when connected to a Gel battery.
The battery charger must be able to deliver a charge current between 10% and 30% of battery capacity.
A Cellpower CPX 80-12 should therefore be charged with a battery charger that delivers between 8A and 24A.
Batteries for standby use
“Standby use” – backup power: Mainly used as emergency power to prevent damage that can be caused by sudden power failure.
Stationary / standby batteries are used for standby use.
The batteries are rarely discharged and continuously maintained in voltage / recharged.
