Wiring to the GEN or GRID port
There are two ways to interconnect a generator to a Sol-Ark: via the GRID or GEN port.
The GEN port is the easiest place to land generators onto a Sol-Ark system. Wiring to the GEN port avoids the need for an automatic transfer switch. While possible to connect larger generators up to 100A, the GEN port will cut out if loads exceed 19.2kW continuous (80A).
Add more inverters if additional generator power is necessary on the GEN port.
If more generator power is needed than 19kW but a second inverter is not an option, or if 100% offgrid, connect the generator to GRID port.
Generators on the GEN Input
Torque GEN port to 165 in-lb / 18.8 Nm
The GEN port is incapable of starting the inverter without grid or battery power.
Not for use with 3 phase generators (on 15K inverters).
Do not share GEN port with other devices when landing generators on the GEN port.
The GEN port can be used for stationary or temporary generators.
Generators on the GRID input
Generators on the “GRID” Input can pass through generator power up to 200A max (180A continuous).
Connecting a generator to the GRID port is capable of starting the inverter on generator power alone, so it is recommended for off-grid installations to connect the generator to the GRID port. Three phase gnerators on 15K inverters must be connected to the GRID port.
Try to avoid generator connections to the GRID port when grid-sellback is necessary. Instead, consider connecting to the GEN port, adding an additional inverter if necessary to increase GEN port ampacity.
Grid Parameters - Generator on Grid Input
Programming “GEN Connect to Grid Input” is required: → Limiter → Other → 🗹 GEN Connect to Grid Input.
Battery Setup Charge Menu
Start V / %: Voltage or State-of-Charge Percent at which the system will 2-wire autostart a generator to charge the battery.
A: maximum charge current (A) rate from the batteries up to a maximum of 275A.
CAUTION: Restrict this amperage to the NEC designated amperage unless battery conductors are sized for 275A or greater!
The GEN or GRID “A” value will constrain generator output capacity to 19kW or less but should not be used with generators larger than 24kW nameplate unless paired with multiple inverters. If connecting more than one Sol-Ark in parallel, the A value refers to the amps of each inverter separately. Multiply the number shown in the A setting by the # of Sol-Ark inverters to get the actual current (A) what will go into the battery bank.
Selecting Grid or GEN charge 🗹 Select Grid charge when a generator is connected to the GRID port to charge from the generator or grid.
🗹 Select GEN charge when the generator is connected to the GEN input
When the generator is connected to the GRID port, the inverter will sense backfeeding and adjust its operating mode. Note: the generator must be sized similar to the inverter nameplate. Otherwise disable grid sellback.
When the grid is detected, battery charging from the grid will charge to 100% SOC.
When the generator is detected on the grid port, the batteries will charge to around 95% to preserve fuel efficiency.
Generator Power Limit
Gen Limit Power: Limits the power drawn from the “GEN” AC source. The inverter will reduce battery charge when value is reached.
For example, if a 24kW generator is landed onto the GEN port, set this value to 19kW.
2 wire autostartThe Sol-Ark inverter can start and 2 wire autostart generator using Gen start relay pins 7 & 8.
The signal comes from a normally open relay that closes when the generator “Start” condition is met.
Setting Generator Autostart
“Start V” or “Start %” is the condition that triggers the automatically generator start command, unless TOU settings are enabled.
Batteries will charge from a generator until the battery bank accepts 5% of its programmed capacity in Amperes (A). This is equivalent to around 95% of the state of charge (SOC).
TOU settings, if enabled, allow adjustment of generator settings.
Weekly Exercise
If a generator has two-wire start compatibility, it will experience weekly generator tests. This test occurs at 8:00AM (local time) every Monday by default. The test takes 20 minutes to complete. The generator will start and stop automatically. The test can be disabled by specifying :00 | 00 min in the "Generator Exercise Cycle Day & Time" option.
Gen Exercise and Force Start
Gen Exercise Cycle (Day & Time): Set a weekly generator exercise schedule. (Day of the week/time/duration length). Necessary to charge the battery of auto-start generators.
Gen Force: Test function for generator auto-start. Enable and press OK to close normally open relay (pins 7,8) and force the generator on. Disable and press OK to disengage. The generator will not provide power during this test if grid power is available.
Change Grid Mode to General Standard If Allowed to Deviate from UL1741SB Grid Profile
To allow for a broader range of operation of the generator,
1. Go to the Grid Setup menu
→ Grid Selection
→ Grid Mode.
→ Choose “General Standard
2. Increase the frequency range of operation: → Grid Setup → Connect → Reconnect
a. Increase “Grid Hz High” to 65Hz.
b. Decrease “Grid Hz Low” to 55Hz.
c. Increase “Grid Volt High” to 275V.
d. Decrease “Grid Volt Low” to 185V.
e. Replicate changes for the “Normal Connect” settings.
Gen Mode with TOU
GEN charging behavior is over-ridden when TOU settings are enabled.
A 🗹 Charge box must be selected whenever a Generator is used with Time-of-Use metering is selected.
Go to the limiter menu.
When a power outage is detected, the generator will charge the battery to amount programmed when 🗹 Charge box is checked (keeping the batteries at 20% in this example).
Wiring Diagrams
Various whole home design options with generator configurations are referenced in the 15K manual.
Generator backup / ESS non-backup panels
Very large home design (i.e. 800A service) may involve backing up multiple service panels, with the Sol-Ark system only backing up a single subpanel.
If designing in such a manner and intending to use grid sellback, adjust allowed grid sellback to less than the home base load during times of generator use.
If unable to do so, disable grid sell-back.
It is encouraged to avoid this design approach, installing enough Sol-Ark inverters to pass through the entire residential service.
Disable Grid Sell when Off Grid
DO NOT use “Grid Sell” in Off-Grid systems. Potential to damage the generator.