Victron energy VE.Net DC Technical Information download pdf (Page 62)

GEL AND AGM BATTERIES

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1. VRLA technology

VRLA stands for Valve Regulated Lead Acid, which means 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.

2. 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 very

high currents (engine starting) than gel batteries.

3. 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.

4. 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 20°C. The self discharge doubles for every increase

in temperature with 10°C.

Victron VRLA batteries can therefore be stored during up to a year without recharging, if kept under cool conditions.

5. Exceptional Deep Discharge Recovery

Victron VRLA batteries have exceptional discharge recovery, even after deep or prolonged discharge.

It should however be stressed that repetitive deep discharge and prolonged discharge have a very negative influence on the

service life of all lead acid batteries, Victron batteries are no exception.

6. 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.

Discharg time

(constant

current)

End

Voltage

AGM

‘Deep

Cycle’

Gel

‘Deep

Cycle’

Gel

‘Long

Life’

20 hours 10,8 100 100 112

10 hours 10,8 92 87 100

5 hours 10,8 85 80 94

3 hours 10,8 78 73 79

1 hour 9,6 65 61 63

30 min. 9,6 55 51 45

15 min. 9,6 42 38 29

10 min. 9,6 38 34 21

5 min. 9,6 27 24

5 seconds 8 C 7 C

Our AGM deep cycle batteries have excellent high current performance and are therefore recommended for high current

applications such as engine starting. Due to their construction, Gel batteries have a lower effective capacity at high discharge

currents. On the other hand, Gel batteries have a longer service life, both under float and cycling conditions.

7. Effect of temperature on service life

High temperature has a very negative effect on service life. The service life of Victron batteries as a function of temperature is

shown in table 2.

Average

Temperature

AGM

Deep

Cycle

years

Gel

Deep

Cycle

years

Gel

Long

Life

years

20°C / 68°F 7 - 10 12 20

30°C / 86°F 4 6 10

40°C / 104°F 2 3 5

Gel and AGM Batteries

Table 2: Design service life of Victron

batteries under float service

Table 1: Effective capacity as a function of discharge time

(the lowest row gives the maximum allowable 5 seconds discharge current)

AGM battery

12V 90Ah

GEL OPzV 2V cells battery

1 2 ... 57 58 59 60 61 62 63 64 65 66 67 68

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Victron energy VE.Net DC Technical Information Page 62

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