Page 198 - Uninterruptible Power Supplies

Batteries
196 Chapter Seven

Liberty 2000 Maximizer vent Cut-away

OFFSET
COVER,
LIBERTY

CUP
VENT
VALVE
(2.5 psi)

GASKET

CATALYST
CAGE
SPARK
ARRESTOR
CATALYST
ASSEMBLY

LIBERTY 2000
PHASE II VENT

Figure 7.10 Liberty 200 Maximizer vent cut-away.

float voltage is reached, usually 2.275 VPC at 20°C or 2.25 VPC at
25°C. (Note: There are slight variations here depending on the manu-
facturer’s design). Figure 7.12 illustrates this (SOC state of charge)
and Fig. 7.13 also gives a good idea of variations to be expected with
varying ambient temperatures.
An intermittent charging regime, claimed to be a benefit to VRLA
life, consists of a cycling charging regime—2 to 3 days on float charge
followed by 2 to 3 weeks idle, with the commitment to resume charging
if battery voltage appears to decrease outside set tolerances. This sys-
tem of intermittent charging claims to reduce the gradual decay in bat-
tery capacity and also increase the life of the cell. There is, however,
conflicting evidence at this moment as to the efficacy of this system.
Various other charging cycles are being tried, mostly varying the times

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