Sunsynk Inverter Configuration (Open Loop)

If closed-loop communication cannot be established and you need to resume operation, you may have to manually convert the Sunsynk inverter-charger to an open-loop configuration. Refer to the latest Discover Lithium battery documentation for battery values and the latest Sunsynk documentation for details on menu navigation and the setup procedure.

NOTE
Depending on your system and particular use case, there may be other settings that require configuration. Refer to the inverter manual for information on these settings.

Set the Discover Lithium batteries to ON and set the inverter-charger to ON.
Using the touch screen and keypad on the inverter-charger, navigate to Main Screen > System Setup > Battery Setup.
Specify the battery settings according to the instructions in the tables that follow.
Touch the OK button to save changes.
Exit and restart the inverter-charger.

NOTE
If using multiple inverter-chargers, configure SUNSYNK inverter-chargers to operate in parallel before setting the parameters for battery operation.

Open Loop - Batt Type

The SUNSYNK inverter-charger will operate in a open-loop configuration using voltage-based parameters if the BMS Lithium Batt parameter is disabled and the AGM V parameter is enabled.

Sunsynk Battery Setup for 2 x HELIOS ESS Batteries

Batt type
Batt type	Select the AGM V option.
Activate	Select this check box.
Batt Capacity	Set to the number of Discover Lithium batteries x Ah capacity of each. For example, set to 628 Ah (2 x 314 Ah) for two HELIOS ESS 52-48-16000 batteries.
Charge Amps	For a single inverter-charger, set to the lesser of the inverter-charger’s maximum charge rate or the quantity of attached batteries multiplied by the battery’s maximum charge rating. For example: Single phase system with 8K-SG05LP1 inverter-charger and two HELIOS ESS 52-48-16000 batteries: Set the 8K-SG05LP1 inverter-charger to the lesser of the inverter-charger’s maximum charge rate of 190 A, or 380 A for two HELIOS ESS 52-48-16000 batteries that are each rated at a maximum charge rating of 200 A. ⁽¹⁾ NOTE: Each HELIOS ESS battery is rated at a 200 A charge rate, but when connected in parallel, the maximum current is limited by internal busbars. For the recommended maximum current for paralleled HELIOS ESS, refer to the table in the Minimum Specifications for Battery Systems topic. Three-phase system with three 8K-SG04LP3 inverter-chargers and two HELIOS ESS 52-48-16000 batteries: Set to the lesser value between the master inverter-charger’s maximum charge rate and the quantity of attached batteries multiplied by the battery’s maximum charge rate divided by the number of inverter-chargers. For example, set the 8K-SG04LP3 inverter-charger to the lesser of the inverter-charger’s maximum charge rate of 190 A, or 133 A for two HELIOS ESS 52-48-16000 batteries that are each rated at a maximum charge rate of 200 A and then divided by three inverter chargers (2 x 200 A ÷ 3 = 133.33 A).
Discharge Amps	For a single inverter-charger, set to the lesser of the inverter-charger’s maximum discharge rate or the quantity of attached batteries multiplied by the battery’s maximum discharge rating. For example, set the 8K-SG05LP1 inverter-charger to the lesser of the inverter-charger’s maximum discharge rate of 190 A, or 380 A for two HELIOS ESS 52-48-16000 batteries that are each rated at a maximum charge rating of 200 A. NOTE: Each HELIOS ESS battery is rated at a 200 A discharge rate, but when connected in parallel, the maximum current is limited by internal busbars. For the recommended maximum current for paralleled HELIOS ESS, refer to the table in the Minimum Specifications for Battery Systems topic. For a three-phase system with three inverter-chargers, set to the lesser value between the master inverter-charger’s maximum discharge rate or the quantity of attached batteries multiplied by the battery’s maximum discharge rate divided by the number of inverter-chargers. For example, set the 8K-SG04LP3 inverter-charger to the lesser of the inverter-charger’s maximum discharge rate of 190 A, or 133 A for two HELIOS ESS 52-48-16000 batteries that are each rated at a maximum discharge rate of 200 A and then divided by 3 inverters (2 x 200 A ÷ 3 = 133.33 A).
TEMPCO	Set to 0 mv/C/Cell. ⁽²⁾

(1) SUNSYNK’s recommended maximum battery value for Charge Amps is 75% of the battery’s rated maximum charge current.

(2) Discover Lithium batteries do not require temperature compensation. Setting TEMPCO to 0 mv/C/Cell disables inverter-charger controlled temperature compensation.

Open Loop - Batt Charge

Sunsynk Battery Charge Settings

Batt charge

Float V

Absorption V

Equalization V

Set the suggested voltage values defined in the associated battery manual.

Discover Lithium batteries must not be equalized. Setting zero hours ensures the batteries will not be equalized.

Open Loop - Shutdown

Sunsynk Battery Shutdown Settings

Shut Down

Shut Down

Low Batt

Restart

48 V

50 V

52 V

NOTE
For more information about configuring the Sunsynk inverter-charger, refer to product documentation on the Sunsynk website (sunsynk.org) or the LYNK II Installation and User Manual (805-0033).