Deye 1Ph LV - single-phase hybrid inverter

What it is

The Deye SUN-SGLP1 is a single-phase hybrid inverter for a low-voltage battery, the 48 V class (nominally 51.2 V, a 16-cell lithium pack). On a site it runs the solar array, charges and discharges the battery, feeds the backup loads and works alongside the grid or a generator. The same inverter is sold under both the Deye and the Sunsynk brand and speaks one protocol either way, so a Sunsynk-badged unit is commissioned exactly like a Deye one.

myPower24 reaches it through the LoggerV, which polls it over Modbus, logs its readings and can hand it to plant control.

In My Devices it is listed as Deye 1Ph LV. Its own nameplate is read off the inverter and shown on the Info tab in the form SUN-12K-LP1, where the number is the rated power in kW. That is the quickest way to confirm you are looking at the size you think you are. On very old firmware that does not report rated power the nameplate falls back to SUN-LP1, with no size in it.

How it connects

The LoggerV speaks Modbus to the inverter, over one of three transports:

• RS-485: Modbus RTU over the serial bus.
• RS-232: Modbus RTU over serial.
• Ethernet: Modbus TCP.

Which one you use comes down to the communication port the unit physically has; see Wiring below. The driver fixes no baud rate on any of the three, so on either serial connection the inverter's rate has to match whatever the LoggerV port's Bus Speed is set to. Neither end is fixed for you.

The LoggerV finds the inverter by actively probing for it. You set a Modbus address on the inverter, the logger reads the identity registers at that address, and it checks the reply came from the single-phase low-voltage family before adopting it. A wrong address or a mismatched baud therefore shows up as a scan that finds nothing, rather than as a device that appears and then misbehaves.

There is no minimum inverter firmware and no minimum LoggerV firmware for the inverter itself. One convenience does have a floor: scanning a range of Modbus addresses instead of a single one needs LoggerV firmware 9.269 or newer, and is offered on serial ports only.

What plant control can do with it

This inverter is an active participant in plant control, not a monitored bystander. It fills three roles at once, and can optionally fill a fourth.

• Hybrid inverter with an off-grid switch. Plant control dispatches battery power by rewriting the inverter's own Time of Use schedule, that is the power and target state-of-charge setpoints behind the six time points. While it is doing that, the inverter carries the notice "Time of Use controlled by plant control". Plant control also caps solar output by writing the PV Power Limit (register 53, in watts), reads the value back to confirm the inverter accepted it. It writes whenever the cap changes, and while a cap is in force it re-asserts that cap at most once every 10 seconds to recover a dropped write. Both of those happen only when Plant Control is switched on under Time of Use/Peak Shifting.
• Energy meter. The reading from the inverter's external CT is presented to plant control as a meter, so a site with no separate meter still has one. This is always on and there is nothing to enable. The meter appears in plant control under the inverter's serial number with an _EM_0 suffix, and it goes online and offline with the inverter.
• Grid connection switch. The inverter's grid connection is registered as a controllable output, named after the serial number with a -GRCP_SW suffix. Opening it forces the inverter into off-grid mode; closing it lets it reconnect.

Reactive power control is not implemented on this model. Plant control can ask for it and nothing happens. Plant control also never starts or stops the inverter: the On/Off control on the device page is an operator action only.

The fourth role is optional. Register Storage, under Settings > Storage Cluster, presents the battery behind this inverter to plant control as a one-battery storage cluster, and logs it as one. Use it only for a battery the LoggerV has no other way of reaching. It takes effect on the next device reload, not when you save it.

What the platform records

Six readings from this inverter are written to the historical record, and are what you get on a chart or in an export:

• Storage Current, A. The battery current.
• Storage Voltage, V. The battery voltage.
• Grid Frequency, Hz.
• Load Frequency, Hz.
• DC Trans. Temperature, °C. Shown on the device page as DC Temperature.
• Heatsink Temperature, °C. Shown on the device page as AC Temperature.

Everything else on the device page, including run state, battery state of charge and all of the power and energy values, is live only. It updates on screen and is not kept. The sampling period is set for the device as a whole; there is no per-reading interval.

Switching on Register Storage adds a second, separate record: the storage cluster's capacity, voltage, current and charge and discharge limits are then logged under the cluster rather than under the inverter.

Wiring

Connection diagrams are generated by the platform's Add-Device wizard; see How to add a device in myPower24. Wire the inverter to the LoggerV on RS-485, on RS-232, or over Ethernet for Modbus TCP.

The inverter has separate ports for the battery BMS, for its energy meter or CT, and for parallel operation. None of those is the monitoring link; use the Modbus communication port.

The inverter's RS-485 terminal labels and pinout, its RS-232 pinout, whether the bus needs a terminator, its factory-default Modbus address, and the LCD menu path for changing the Modbus address and baud rate are all in the SUN-SGLP1 manual. Check it before you make up a cable.

Setting it up

1. Connect the communication cable per the generated diagram.
2. Add the device on the LoggerV; see How to add a device in myPower24. Choose the Deye SUN-SGLP1 device type and set the port's Bus Speed to match the inverter.
3. Enter the inverter's Modbus address. If you do not know it, use Try scan range and enter a range such as 1-10, or a comma-separated list of addresses, in Modbus Slave address begin:. Addresses run from 1 to 254. The button appears on serial ports only, and needs LoggerV firmware 9.269 or newer.
4. On the inverter, set a Modbus address that is unique on that bus, and a baud rate that matches the LoggerV port.
5. Set the grid code, under Settings > Setup > Grid Standard. It fixes the inverter's voltage and frequency limits and its trip times, so it has to match the country you are installing in.
6. Set the battery up on both ends, as below.
7. Check it worked. Open Actual Data: Run State should read Normal, and Battery SOC, Inverter Power and Grid Power on the Status card should be updating.

Battery communication

The battery talks to the inverter directly over a CAN link, so the inverter charges and discharges it from the battery's own BMS rather than from a voltage curve. Both ends have to be told to speak the same protocol, and getting either one wrong is the usual reason a freshly commissioned site shows no battery data at all.

On the inverter, on the device page under Settings > Battery:

• Control Mode: set it to Lithium Battery for any battery with a BMS. This is register 200. The other choice is Lead Battery, which makes the inverter follow absorption, float and equalisation voltage curves instead.
• Lithium Battery Type: the battery's BMS protocol, entered as a number. This is register 325. For a Solar MD battery, set it to 0. It is only read when Control Mode is Lithium Battery.
• Battery Capacity, Max Charge Current and Max Discharge Current: set to the pack's ratings. Capacity in Ah, the two currents in A.

On a Solar MD battery, tell the battery which inverter it is driving. On the battery's own device page go to Settings > Installer > Control, find Controlled Device Settings, and set Controlled Device: to Sunsynk. Deye and Sunsynk share one protocol and there is no separate Deye entry in that list. The battery side is covered in full in Li-ion Storage EX - battery.

The battery protocol code can also be set at the inverter's own LCD instead of through myPower24. The menu path for it is in the SUN-SGLP1 manual.

On the device page

The page has four tabs, and Actual Data opens first.

• Info: manufacturer, device name, install date, hardware version, and the four firmware values the platform reads off the inverter itself (Main Ctrl FW, Modbus Protocol, Bootloader and LCD FW). It also carries the inverter's own date and time, the Modbus connection details, and a nameplate card with rated power, MPPT count, battery count and grid standard.
• Actual Data: nine cards. Status, Battery Data, Load Data, Grid Data, Inverter Output, Mppt Info, Aux / Generator, System Energy Totals and Temperature & Relay.
• Settings: seven groups. Setup, Battery, Storage Cluster, Grid, Gen Port, Protection and Output. The On/Off control sits at the bottom of Setup.
• Time of Use/Peak Shifting: the Plant Control switch, the day-by-day Time of Use enables, and the six time points, each with its time, discharge power limit, cut-off battery voltage, target state of charge and charge source. Two settings tune what plant control does here: Plant Control SOC Limit (%), the state of charge it stops discharging at, applied to all six time points, and Plant Control Write Interval (ms, default 3000, range 1000 to 60000), the minimum spacing between its setpoint writes.

A healthy link reads Run State: Normal on the Status card, with Battery SOC, Inverter Power and Grid Power moving. Run State takes one of six values: Standby, Self-check, Normal, Alarm, Fault and Hard Fault.

The inverter also raises its own events as the grid comes and goes, so you will see "Grid connection lost" and "Grid reconnected" in the device's events. Temperature & Relay shows the Grid Port Relay Status and Gen Port Relay Status as Open or Closed.

Troubleshooting

• The inverter does not appear after a scan. Almost always address, baud or wiring. Check A and B are not swapped, that the baud matches the port's Bus Speed, and that you scanned the address you actually set. A range scan takes the address out of the question.
• "Wrong Deye model family at Reg 0!" The unit answered, but it is not a single-phase low-voltage inverter. A three-phase or high-voltage Deye will not adopt on this device type; add it under its own type instead. The rest of the message names the family code it expected and the one it found.
• "External CT clamp appears disconnected", as a warning. Raised when the external CT total sits at exactly 0 W for 60 consecutive polls while the inverter is on-grid and its internal grid sense is clearly active. Usually an unplugged, open or mis-wired CT clamp. Check the clamp and its orientation. The warning clears itself once current is read again. The rest of the message quotes the two grid power readings it compared.
• No battery or BMS data. Both ends have to agree: inverter Control Mode set to Lithium Battery with the right Lithium Battery Type, battery Controlled Device: set to Sunsynk. Then check the CAN cable. A lost link raises the inverter's own Bat_Comms_Lost fault, F58. If the pack has gone to sleep, Settings > Battery > Lithium Battery WakeUp sends it a wake-up.
• "Failed to set:" followed by a setting name, when saving a Time of Use day switch. The write to the inverter did not go through. Check the inverter is still online, then retry.
• Battery power and current stop updating while Plant Control is active. This inverter pauses its live-data registers for a while after every write, so writing setpoints too often starves the readings the control loop depends on. Raise Plant Control Write Interval under Time of Use/Peak Shifting > Setup above its 3000 ms default.
• Register Storage appeared to do nothing. It only applies on device reload, so reload the device.
• A fault code you do not recognise. The inverter's own fault codes are passed through unchanged, as an F-number and the vendor's own name for it, for example F35 No_AC_Grid, F34 AC_Overload_Fault, F64 Heatsink_HighTemp_Fault, F61 Button_Manual_OFF or F29 Parallel_comm_Fault. Several codes the vendor never documented show as "F19 UNKOWN" and similar, misspelling included. Look the code up in the inverter's own manual.

Who can do what

• Regular user (basic): everything. Open the page, read the live data, and change every setting on the Settings and Time of Use/Peak Shifting tabs.

Nothing on this device page is gated above basic. There is no advanced and no oem step for this inverter: the grid code, the protection limits, the grid voltage and frequency trip points, the Time of Use schedule and Factory Reset Enable all sit at the same level as reading the battery voltage.

What decides whether you can change anything is your access to the plant, not your tier. A user without configure access on the site sees the banner View-only on this site. and their saves are refused. If a save comes back with "Permission denied! Required permission [basic].", the cause is your access to that plant, not the setting you touched.

Tips and gotchas

• PV Power Limit is shared. It appears as an operator setting under Settings > Output, and plant control writes the same register while it is curtailing. With plant control on, treat the field as read-only: it will be overwritten whenever plant control moves the cap.
• The Time of Use schedule is not yours while plant control has it. With Plant Control switched on, the six time points' power and state-of-charge values are rewritten automatically. Switch it off before hand-editing them.