Solis 5G Hybrid Inverter Troubleshooting Guide [RHI-1P(5-10)K-HVES-5G]

CONTENTS

SECTION 1: PRODUCT

SECTION 2: DATASHEET

SECTION 3: SYSTEM FUNCTION OVERVIEW

SECTION 4: ZERO EXPORT FUNCTION

SECTION 5: PV INPUTS

SECTION 6: RAPID SHUTDOWN

SECTION 7: FIRMWARE VERSION AND UPGRADE 

SECTION 8: AUTO-TRANSFORMER (ATR)

SECTION 9: TIME CHARGING SETUP

SECTION 10: MAXIMIZE SELF CONSUMPTION SETUP

SECTION 11: OFF-GRID MODE SETUP

SECTION 12: TROUBLESHOOTING


SECTION 1: PRODUCT

The 5G RHI is a residential hybrid inverter built specifically for the US. It was developed to meet the specific requirements of California and NEC 2017. The inverter is designed to work with high voltage lithium ion batteries specifically within the inverter's MPPT operating range. That means that all Lithium Ion batteries within the range of 120-450 can work with the inverter, but they must be specifically certified with the inverter in order to be installed in the United States. That certification is called UL 9540 and is different from the UL 9540A (the fire safety standard test for the battery). The UL 9540 is specifically certifying the battery and the inverter together as a unit focusing on charging and discharging the battery.


US Product Manager – Michael Allen – Michael.allen@solisinverters.com


De-abbreviation for RHI-1P(5-10)K-HVES-5G

RHI – Residential Hybrid Inverter

1P - Single Phase 

5-10K - Power sizes are from 5K to 10K

HV – High Voltage (120-450VDC Lithium ion batteries)

ES – Energy Storage  (Battery Compatible)

5G – 5th Generation (with 28062 DSP)


SECTION 2: DATASHEET

SECTION 3: SYSTEM FUNCTION OVERVIEW

The hybrid inverter has multiple purposes that need to be understood in order to properly troubleshoot the system. To begin let’s go over all of the capabilities and functionalities of the inverter.

1. Time Charging – Otherwise known as “Time of Use” (TOU) or “Energy Arbitrage”, this function allows the battery to be charged during “off peak” hours when the price of power is low or the rate of production (solar charging) is high and discharge when the price of power is high or the rate of production is low OR non-existent (night time). Around the US we have many different utilities that have these “peak” and “off-peak” schedules that tell their customers when the price of power is high or low. Our inverter can schedule these times within the inverter’s user interface.

2. Off Grid Function – The RHI can fully function and support “loads” when the grid is offline. At the point of change from “on-grid” to “off-grid” the inverter changes from voltage control mode to current control mode. The inverter will NOT be supporting the full load of the home (unless it’s a tiny home). It can only backup 6kw of continuous power. That being said 6kW of continuous power is quite a bit of power and can potentially cover all of the home owners loads but the inverter is not bult to be a whole home backup. One reason is this. The inverter can be paired with a BYD 10kWH and a LG Chem 10kWH battery. If you are running 6kW of continuous load then you will only be running that backup load for about 1.5 hours when the solar charging is offline. If the homeowner has 2 LG Chem batteries then that is only 3 hours which won’t cover the homeowner for the night time consumption. Most loads like a refrigerator, LED lights, computer chargers, WIFI router are extremely small loads and will only amount to together of 800-1000 watts. That is what the installer needs to shoot for. We need to recommend only about 1-2kW of off grid loads. Otherwise the homeowners will be unsatisfied when the power runs out and their loads only run for 2-3 hours.

3. Self-Consumption – This feature is called “Auto” or “Maximize self-consumption rate” within the manual. The feature allows the user to store excess PV power into the battery and discharge it when the PV generation is low or non-existent automatically. Below is a graph to help you understand this feature:

Figure 1 - Self Consumption

It’s important to understand that this mode will most likely deplete the whole battery during the night time. The inverter has an external meter that is measuring the load of the “WHOLE HOME” therefore it will discharge to match the whole home load and not just the backup panel. This is ideal if the homeowner has the mindset of zero carbon footprint but not ideal if they have the battery specifically for backup. Until loads get smaller or batteries get bigger, we will have to constantly remind customers that they need to choose one over the other.


SECTION 4: ZERO EXPORT FUNCTION

The Zero export function is an important part of the system. It allows the Solis hybrid to be sold in territories like Hawaii where it is mandatory. It also is more than a “ZERO” export function. It’s more of an adjustable export function. The customer can tailor exactly how much they need to export in order to meet their needs and to reduce their bill to zero.

In order to set it to a custom setting – go to Advanced Setting – Export Power Set and set it to the amount that is needed. The second picture shows zero export.

Figure 2 - Export Power Set

Figure 3 - Zero Export LCD


SECTION 5: PV INPUTS

The RHI series can handle two strings PER channel. At this point in time we do not recommend to parallel strings. There needs to be further testing on if the parallel strings can damage the Rapid Shutdown transmitter. Also note that the DC inputs are not side by side + and -. Its important to see if the customer wired up the inverter correctly. I foresee customers doing this incorrectly and needs to be looked out after because it will void the warranty even though we have reverse polarity protection. That protection will only last until it burns out the diode.

MPPTS – 2

Total PV Inputs – 4

Max Current Per String – 11 amps

Figure 4 - DC Inputs


SECTION 6: RAPID SHUTDOWN

Each PV string has a rapid shutdown PLC (power line communication) signal generator on the string. The PLC signal generator is a certified Sunspec rapid shutdown generator. Later versions might have a Tigo transmitter installed but not at this time (7.10.2020). Early indications of parallel string setup is hinting at damage the PLC generator so it’s recommended to not use the strings in a parallel environment until further testing is completed.

Location: The rapid shutdown PLC generator is located behind the AC connections/ battery and meter communication boards. The only way to access the board is to remove the front panel, front board, wire connections and back panel.

Figure 5 - Wiring Box

Figure 6 - RSD Board


SECTION 7: FIRMWARE VERSION AND UPGRADE

To verify the firmware version, go to “Info” – “General Info”

The firmware version is under Software Version

The below picture shows 060007 – (HMI = 06 / DSP = 07)

Figure 7 - General Info Screen with Firmware Version

How to update the DSP and HMI Firmware

HMI Update

File: HMI.bin

Process: Advanced Setting – Software Update – HMI Update – Insert Tool – Hold FW update button until all of the lights are lit – Fast Click FW update button – Verify FW is updated on the screen

DSP Update

File: 28062APP.bin + 28062API.bin

Process: Advanced Setting – Software Update – DSP Update – Insert Tool – Hold FW update button until the Green and Red are lit – Fast Click FW update button – Verify FW is updated on the screen


SECTION 8: AUTO-TRANSFORMER 

WARNING The backup settings need to be set appropriately. As of today, the inverter does not switch to 240VAC/60HZ backup when a US grid standard is selected. Product team has requested to update the backup settings when a US grid standard is set. This will be in the next firmware patch. Today if you order an inverter the backup settings will be as follows:

These have to be adjusted or you could potentially damage your backup loads or the inverter.

First of all, what in the hell is an auto-transformer and why do we need it. We need the ATR because our inverter puts out 240VAC output with no neutral. L1 + L2 equal 240VAC with reference zero to ground. If the homeowner only wants to output 240VAC to the backup panel then there is no need for an ATR. The homeowner has 110Vac loads therefore we need to split the 240VAC in half and generate a neutral. This is where the ATR comes into play.

Figure 8 - ATR Schematic

The ATR is a 6kW fully imbalanced capable auto-transformer. That means that it can support its full load completely on one side of the transformer. A total of 30 amps. Why do I say one side? That is because there is a L1-N and L2-N that we have on the output of the ATR. If you have one load that is 25 amps it can only be placed on one line so the ATR has to fully support the 30-amp imbalance.

Figure 9 - ATR Datasheet

Figure 11 - System with Battery Backup and ATR

Figure 10 - Inside the ATR


SECTION 9: TIME CHARGING SETUP

Time Charging = Time of Use = TOU

Time Charging – Time charging is very easy to setup. One thing that people will overlook is the discharge limit. I believe that the discharge limit shall be changed base on the battery size. It’s very easy to do the math.

Battery Size - 10kWh

Battery Discharge Current - 10-amps

Battery Discharge Power -10-amps x 240VAC = 2400 Watts

10kwh/2.4kw = 4.167hours

That means that if the customer has a discharge time of 5 hours it will completely deplete the battery and will go into a force charge. If it’s night time then the battery will charge from the grid, but if it’s in California the battery will not be able to charge and the battery will have to wait until the PV starts generating in the morning in order to charge the battery.

Process:

1. Go to Advanced Setting – Storage Energy Set – Time Charging

2. Set Optimal Income to “RUN”

3. Adjust Discharge limit to the battery size

4. Set Charge and Discharge time to your local utility peak rates

5. Press Esc

6. Save and send


SECTION 10: MAXIMIZE SELF CONSUMPTION SETUP

Maximize Self Consumption rate is the safest mode to be. At every point we should be promoting this mode. Off-Grid and Time of Use come with their problems because you are introducing variables that can be difficult to work with such as dealing with the ATR, back up panels, large loads or long discharging times. Thus, if anybody asks, “What mode do you suggest we use?”. We all need to be messaging “Maximize Self Consumption”. Explanation is above.

Maximize Self Consumption is not a “selectable” mode per say.

Process:

1. Go to Advanced Setting – Storage Energy Set – Time Charging

2. Set Optimal Income to “Stop”

3. Press Esc

4. Save and send

5. Go to Advancing Setting – Storage Energy Set – Off-Grid Mode

6. Set Off-Grid Mode to “Off”

7. By setting both Time Charging and Off Grid mode to off you will enable Maximize Self Consumption Rate.


SECTION 11: OFF-GRID MODE SETUP

Off-Grid capability is probably the most amazing part of the inverter. The inverter switches from Voltage Control Mode to Current Control Mode and that in itself is amazing engineering. The Off-Grid mode itself is kind of a strange mode to be honest. With Off-Grid Mode you can still have a grid. The whole mode itself is kind of trumped by the feature of Backup Control option. With Backup Control you can turn your backup port on and run it and if the grid goes out the backup port will continue to run. Off-Grid mode will probably be useful when the inverter will only run in Off-Grid mode at all times for example when using the inverter to run a cellular tower in the middle of nowhere with no power. For the most part we won’t see the mode ran in the US but we might in in LATAM.

Process:

1. Go to Advancing Setting – Storage Energy Set – Off-Grid Mode

2. Set Off-Grid Mode to “On”

3. The grid will still remain until a firmware update is completed.

4. We expect when the Off-Grid mode is selected, the grid should only run off of the backup port.


SECTION 12: TROUBLESHOOTING

Alarm Message – NO Battery

Explanation – This means that “No battery” is selected in the battery select settings

Possible Solution – if there is a battery installed, go to advanced settings and select the proper battery and verify the message goes away after the battery establishes a connection. Typically, it’s very fast. Also check to make sure the battery is on (breakers within the battery)

Figure 12 - No Battery

Figure 13 - LG Chem breakers (2)

Alarm Message – LG OV DDC

Explanation – LG Chem battery throws this alarm. This alarm is for over voltage on the DC input.

Possible Solution – The only current solution for this is to reset both LG Chem battery breakers and this will fix the problem. If that doesn’t work select “No Battery” and reselect the LG Chem.

Figure 14 - LG-DDC-OV

Alarm Message – AC Overcurrent

Explanation – This happens when the AC output current raises beyond the limitation of the inverter. The alarm will typically happen only when the system is in off-grid mode.

Possible Solution – The only time this happened is when the firmware HQ sent to me was incorrect (for LV hybrid inverter). The inverter kept tripping over and over. Once I loaded the proper firmware the issue went away.

Alarm Message – Arc Fault

Explanation – This happens when the inverter detects an arc between two connections in the DC String. Typically, the arc happens on a homerun or a bad MC4 connection

Possible Solution – First and foremost it’s important to realize that the arc fault detection could be an actual arc fault detection. The technician onsite needs to do the basic troubleshooting before the next steps are warranted. The great part about the hybrid inverter is it comes with a special menu – go to advanced setting and put in the code 2017 – Within the advanced setting menu adjust the AFCI sensitivity to a lower level and that will allow the technician to set the detection at a point that is still safe and yet mitigates all of the noise on the line that is tripping the arc fault detection board.

Figure 15 - Arc Fault Message

Alarm Message – Grid power on screen doesn’t match what I’m exporting from Solar and battery

Explanation – It’s important once the technician commissions the system to ensure the power flow is correct. As you can see on the screen below the arrows from Solar and the battery are exporting outwards ~5.6kW’s. Yet the homeowner shows he is drawing about 4.6kW’s from the grid.

Possible Solution – With this situation it’s almost always the CT’s are reverse. It’s very easy to install the CT’s faced in the wrong direction and even today I am still confused on the appropriate direction.

Figure 16 - Incorrect flow of power

Figure 17 - CT's on service panel

Alarm Message – 0Vdc on strings with RSD devices installed (APSmart or Zerun)

Explanation – The inverter will either be off or one or two strings will be reading 0Vdc.

Possible Solution – Typically this will happen on initial install. The installer will be confused on what is required. Remember that the inverter can initiate the RSD PLC Signal until the AC Voltage is applied. Verify the AC Voltage is applied and have the installer verify the voltage inside the wiring box.

With the APSmart RSD devices they put out .6-.7Vdc per panel when the device is open. So, if you have 10 panels, you should have around 6 or 7 volts when you measure at the PV inputs at the inverter. If you have 0 volts then you have an issue

This is a brand-new addition to our inverters to there isn’t much historical information on the possible repairs. For the time being if one or two strings are on and some are not it’s most likely an RMA. If all strings are offline and AC Voltage looks good, it most likely is also an RMA.

M
Michael.allen is the author of this solution article.

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