Xantrex Technology 120 VAC/60 - Manual (Page 53)

MENU SYSTEM
 2001 Xantrex Technology, Inc.
5916 - 195th Street N. E.
Arlington, WA 98223
Telephone: 360/435-8826
Fax: 360/435-2229
www.traceengineering.com
SW Series Inverter/Charger
Part No. 2031-5
Rev. C: February 2001
Page
45
INVERTER SETUP (9) MENU HEADING
Set Grid Usage
FLT SELL SLT LBX
•
FLT - Float will try to maintain the batteries at the float voltage level. This can be used when the
source of power is a utility grid or a generator. When AC power is available, the inverter will complete
a full three stage charge cycle and then hold the battery at the float level until the source of utility
power is no longer available. This is the default setting and is appropriate for use with stand-alone
systems with back-up generators or utility back-up systems. FLT mode does not sell excess power
into the utility grid. If a DC power source is available and the battery is full, its power will be used to
directly power the AC loads connected to the inverter output even though the AC power is also
connected to the loads. If more power is available from the DC source than is required to power the
AC loads, the battery voltage will increase above the float level. An external charge control device –
such as the Trace™ C40 Load/Charge controller - is therefore required to prevent over charging of the
battery.
•
SELL – SELL mode enables the inverter to “sell” the excess power to the grid (AC HOT IN 1
only). This mode must have the approval of the local power utility prior to its use. In the US,
utility companies are required by law to purchase any excess power generated by their customers;
however, they decide what can be connected and what safety requirements must be met. Be advised:
some utilities will be more receptive than others will. The most advantageous configuration is called
“NET” metering where only one meter is installed and spins either direction. The purchase and sell
prices are equal. “Dual” metering requires two meters and is less desirable since the power you sell is
usually worth only a fraction of the price for the power you purchase. Power from any DC source, such
as a solar array, and a battery can be sold. When power from a DC source is available, it will be used
to power any AC loads connected to the AC output first. Any excess power available from the system
will be sold “into” the utility gird through the AC HOT IN 1 terminals.
•
SLT - The silent mode does not maintain the battery at float voltage all the time. The battery
charger only operates for part of each day. AC power from the utility grid is passed through the
inverter to the loads 24 hours a day. Once a day, at the time prescribed by the BULK CHARGE
TRIGGER TIMER, the batteries are given a bulk and absorption charge cycle. The inverter will
perform a bulk charge once per day from the grid, charging the battery to near the SET BULK VOLTS
DC setting until the battery charger has held the battery near the SET BULK VOLTS DC setting for
the ABSORPTION TIME period setting. The inverter will then go totally silent and will wait for the utility
power to fail, or until the next day when it performs another bulk charge. After each power outage, the
inverter will perform another bulk charge cycle once the AC source has returned. This is typically used
only in utility back-up applications.
•
LBX - The low battery transfer mode allows a system to automatically switch between utility
connected and stand alone battery operation. In this mode, the inverter will power the loads from
the battery and solar array (or other energy source) until the battery voltage drops to the LOW
BATTERY TRANSFER VDC setting. It will then connect to the utility grid and charge the battery. The
loads will be powered by the utility until the battery voltage reaches the LOW BATTERY CUT IN VDC
setting. The inverter will then disconnect the utility and power the loads from the battery and any other
source of DC power connected. This mode is often used instead of the SELL mode because approval
from the utility is not required - no power will be sent into the utility distribution system when LBX is
selected. To use the LBX mode, the AC source (utility power) must be connected to AC1 input only,
transfer to the inverter will not occur if the AC source is connected to the AC2 input. If AC is present
on the AC1 input in the LBX mode, the AUTO GENERATOR CONTROL MODE will be disabled.
CAUTION: If the system is not properly sized, the LBX mode can result in frequent transfers
from the battery to the utility and result in poor performance of the system and excessive
energy consumption from the utility. The daily output of the alternative power source (solar,
wind etc.) should be able to meet the daily power requirements of the loads being operated
under typical conditions. See the low battery transfer mode section for more information.