Victron AGM Deep Cycle Battery - 12V

The AGM range has very low internal resistance making them particularly suitable for high current discharge applications such as for inverters, thrusters and winches.

VRLA technology

VRLA stands for Valve Regulated Lead Acid, which means that the batteries are sealed. Gas will escape through the safety valves only in case of overcharging or cell failure. VRLA batteries are maintenance free for life.

Sealed (VRLA) AGM Batteries

AGM stands for Absorbent Glass Mat. In these batteries the electrolyte is absorbed into a glass-fibre mat between the plates by capillary action. As explained in our book ‘Energy Unlimited’, AGM batteries are more suitable for short-time delivery of high currents than gel batteries.

Battery Discharging Characteristics

The rated capacity of Victron AGM and Gel Deep Cycle batteries refers to 20 hour discharge, in other words: a discharge current of 0.05 C. The rated capacity of Victron Tubular Plate Long Life batteries refers to 10 hours discharge. The effective capacity decreases with increasing discharge current (see table 1). Please note that the capacity reduction will be even faster in case of a constant power load, such as an inverter.

Battery charging in case of standby use: constant voltage float charging

When a battery is not frequently deeply discharged, a 2-step charge curve can be used. During the first phase the battery is charged with a limited current (the bulk phase). Once a pre-set voltage has been reached the battery is kept at that voltage (the float phase). This charge method is used for starter batteries in vehicles and in uninterruptible power supplies (UPS).

Optimum charge voltage of Victron VRLA batteries

The recommended charge voltage settings for a 12 V battery are shown in table 3.

Effect of temperature on charging voltage

The charge voltage should be reduced with increased temperature. Temperature compensation is required when the temperature of the battery is expected to be less than 10 degree C/50 degree F or more than 30 degree C/85 degree F during long periods of time. The recommended temperature compensation for Victron VRLA batteries is -4 mV / Cell (-24 mV/degree C for a 12V battery). The centre point for temperature compensation is 25 degree C / 70 degree F.

Charge current

The charge current should preferably not exceed 0.2 C (20 A for a 100 Ah battery).The temperature of a battery will increase by more than 10 degree C if the charge current exceeds 0.2 C. Therefore temperature compensation is required if the charge current exceeds 0.2 C.

Victron AGM Deep Cycle Battery Datasheet