Sealed (VRLA) Gel Batteries
Here the electrolyte is immobilized as gel. Gel batteries in general have a longer service life and better cycle capacity than AGM batteries.
Low Self-Discharge
Because of the use of lead calcium grids and high purity materials, Victron VRLA batteries can be stored during long periods of time without recharge. The rate of self-discharge is less than 2% per month at 20C. The self-discharge doubles for every increase in temperature by 10C.
Victron VRLA batteries can, therefore, be stored for up to a year without recharging, if kept under cool conditions.
Exceptional Deep Discharge Recovery
Victron VRLA batteries have exceptional discharge recovery, even after deep or prolonged discharge.
Nevertheless, the repeatedly deep and prolonged discharge has a very negative effect on the service life of all lead-acid batteries, Victron batteries are no exception.
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.
Effect of temperature on the service life
High temperature has a very negative effect on service life.
Cycle life of Victron batteries
Batteries age due to discharging and recharging. The number of cycles depends on the depth of discharge
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 charging 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 12V 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
the temperature of the battery is expected to be less than 10C / 50F or more than 30C / 85F during long periods of time.
The recommended temperature compensation for Victron VRLA batteries is -4 mV / Cell (-24 mV /C for a 12V battery).
The center point for temperature compensation is 25C / 70F.
Charge current
The charge current should preferably not exceed 0,2C (20A for a 100Ah battery). The temperature of a battery will increase by more than 10C if the charge current exceeds 0,2C. Therefore temperature compensation is required if the charge current exceeds 0,2C.
