Conext SW 4048-120 Manual Addendum

Documentation Update
976-0315-01-01 Rev E 5
controlled by the MPPT charger so that they can control the state-of-charge of
the batteries. AC power from the grid is utilized only when load demand exceeds
power available from the MPPT charger for charging and supplying the loads.
When enhanced AC support mode is enabled, the CSW automatically tracks the
MPPT solar charge controller’s charging voltage as it transitions from bulk to
absorption to float. By tracking the voltage, the CSW is then able to execute and
finish the charging cycle using DC power from the solar charge controller while
converting its excess DC power to AC power to support the grid by supplying
more current. CSW only uses excess DC power not required by the battery to
support the grid thus, it prioritizes charging the battery before supporting the
loads. Battery health is improved because the system always executes a three
stage charging of the battery that ensures battery SOC is as close as possible to
100% at all times. Systems that use a fixed voltage for AC support (or similar)
start to support loads sooner and may not fully charge the battery bank, leaving
the battery in a partial SOC. Prolonged periods of partial SOC can degrade
battery performance. Enhanced AC support limits this degrading effect.
Figure 3 Enhanced AC Support
MPPT Solar
Charge
Controller
Conext SW
Battery
Bank
SCP
AC Loads
AC OUTAC IN
DC
Grid
Solar Array
NOTE: Entry and exit into
Enhanced AC Support is
determined by the MPPT.
15 A< 2 A*
> 13 A
* To prevent injecting current into the grid from the inverter, there is less than 2 amps of offset allowed
from the grid to flow into AC IN under all conditions.
Figure 4 Enhanced AC Support Charge Cycle
15
17
19
21
23
25
27
29
-200
300
800
1300
1800
2300
11:20 11:50 12:20 12:50 13:20 13:50 14:20 14:50
BULK ABSORPTION
BATTERY VOLTAGE
CHARGE CONTROLLER
OUTPUT POWER
AC SUPPORT
POWER
POWER TO BATTERY
FLOAT
TIME
BATERY VOLTAGE
POWER