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www.enersys.com Publication No. US-FL-IOM-002 January 2007
8.0 INITIAL and/or FRESHENING CHARGE
Batteries lose some initial charge during shipment and storage. Depending on storage time, a
battery may require a
freshening charge
. See Section 4.0 for battery storage times.
Before switching on the charger, ensure that shipping vent plugs are removed and flame
arrestors are installed.
Do NOT attempt a freshening charge unless the electrolyte levels are near the low level
line on open circuit. When necessary, remove electrolyte to that level from cells with
high levels.
Most chargers of modern design utilize the principle of constant voltage (potential) charging.
The preferred charge method is to use a constant voltage of 2.50 volts per cell times the
number of cells. If this voltage is too high for the equipment (load) connected to the DC bus, the
use of lower voltage is accceptable. See Table 8.1. Should the charge current cause electrolyte
to flood out onto the cover, reduce the charge voltage at once.
Least desirable is to put the battery on at the float voltage - particularly for calcium alloy cells.
Equalize charging at 2.33 volts per cell is the minimum acceptable procedure for 1.215 calcium
alloy cells.
1.
Determine the maximum voltage that may be applied to the system equipment (or
maximum charger voltage if load is not yet connected). Refer to the recommendations of
the manufacturer/supplier of system equipment, connected to DC bus.
2.
Divide the maximum total system voltage by the number of cells (not units) connected in
series. This is the maximum volts per cell that may be used for the initial charge.
3.
Check the nameplate to determine whether the battery is of a lead-antimony type or a
lead-calcium type.
4.
Connect battery positive (+) terminal to charger bus positive (+) terminal.
5.
Connect battery negative (-) terminal to charger bus negative (-) terminal.
Summary of Contents for PowerSafe Data Safe
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