METREL MI 3205 - Precharge

MI 3205 TeraOhm XA 5kV Safety and operational considerations
9
Typical charging profile which is also used in this instrument is shown in Figure 2.4.
Figure 2.4: Typical charging profile
where:
V
REG
............................... Battery charging voltage
V
LOWV
.............................. Precharge threshold voltage
I
CH
................................... Battery charging current
I
CH/8
................................. 1/8 of the charging current
2.2.1 Precharge
On power up, if the battery voltage is below the V
LOWV
threshold, the charger applies 1/8
of the charging current to the battery. The precharge feature is intended to revive deeply
discharged battery. If the V
LOWV
threshold is not reached within 30 minutes of initiating
precharge, the charger turns off and a FAULT is indicated.
Figure 2.5: No battery indication
Note:
 As a safety backup, the charger also provides an internal 5-hour charge timer for
fast charge.