Grid And Backup Connection - Alpha ESS SMILE-G3-S3.6 Installation, Operation & Maintenance Manual

44
Description
Grid Side
Backup Side
Description
Grid Side
Backup Side

6.3.2. Grid and Backup Connection

Use the AlphaApp or Alphacloud to select the current rating of the circuit
breaker used to protect the ac wire connecting to the Inverter. The Battery
System is programmed to limit the Battery Charge rate (from the grid) depending on
the Backup circuit current and on the size of the MCB used. This avoids the risk of
the backup circuit combining with a force-charge or VPP charge and pulling too
much current through the grid-supply ac cable/MCB.
Note that an Automatic Transfer Switch can be used to bypass the battery ac cable
and backup connection if preferred.
plug will be 0A until there is a power outage. This means that the MCB on the ac
supply to the battery only needs to be sized for the maximum current rating of the
inverter (i.e. 21.7A for a 5kW inverter).
The combined current of the Battery Grid-charge and the Backup Circuit will be
limited to the current rating of the MCB less 2A (to account for temperature de-rating
of a typical MCB). Installers must advise Alpha if the MCB used has a steeper de-
rating factor where the 2A buffer would not be sufficient.
Example: If a 32A MCB is used and the backup circuit is drawing 15A, any force-
charging of the battery will be limited to (32A-2A) – 15A = 15A. If the Load on the
backup circuits drops to 11A, the maximum grid-charge current would increase to
19A.
Max. Current
40A 32A or 40A depending on maximum Load
10mm
21.7A
Max. Current
31.2A 25A, 32A or 40A - check MCB de-rating
15.6A
Breaker Type for Smile-G3-S5/B5-INV
on the backup circuit – check MCB de-
rating data for the expected maximum
temperatures. Maximum wire gauge is
2 for the Plug at the Inverter side.
32A
Breaker Type for Smile-G3-S3.6-INV
data for the expected maximum
temperatures.
32A
In this case, the current on the Backup Output