Hello,

I am planning to build a 6 kW hybrid solar system that would have 48V batteries and also export excess energy to grid.

I am currently researching which inverter to choose and I am tempted to go with Deye.

However, after reading the manual and forums as well as watching a lot of youtube videos it is still unclear to me if priorities can be set up such that:
1) if solar is available use that first
2) if no solar (night), then use only batteries (until a low threshold is reached)
3) only as a last resource use the grid
4) in all cases, excess solar should be exported to grid
5) never use grid to charge batteries

Some other chinese inverters like the Easun have the SBU mode (solar-battery-utility priority) which is pretty self explanatory, but for the Deye I'm having a hard time figuring out if an equivalent setup can be achieved.

I also see that Deye supports "non-essential loads" circuit that requires a CT as well as an "essential loads" circuit where the loads get connected through the inverter.
It is my understanding (correct me if I'm wrong) that the non-essential side would still consume at least a small amount of grid energy even if it is set to last priority as it would be necessary for the CT to record such a consumption before the inverter would adapt to force only solar/battery energy usage. In this case, am I right in saying that if I want truly 0 grid consumption I should just connect all loads (house, everything) to the "essential loads" circuit and just non bother with the "non-essentials" at all?

Thank you

 

 

1) if solar is available use that first
2) if no solar (night), then use only batteries (until a low threshold is reached)
3) only as a last resource use the grid
4) in all cases, excess solar should be exported to grid
5) never use grid to charge batteries

1 - yes

2 - yes

3 - Yes, but why? The grid is effectively a battery from which you can draw as required, when Sun + battery is not enough.

4 - Not sure, because at night your battery will also export its charge to grid if there is no solar. Youd need a switch to tell the inverter not to export at night???

5 - Yes..

Hi @ultrasbz

If your utility power meter allows for feeding back into the grid you can change the zero-export power to 0. 

The reason there is a value there is so as to help prevent accidental feedback into the grid when the load changes rapidly on the inverter. Some of the Utility meters are very sensitive to feeding back into the grid and trip out if they detect and feedback, increasing the Zero-Export Power value helps prevent the accidental feedback.

If you are feeding back into the grid that would not be an issue.

The difference between the Backup Load and On-Grid Home Load is that only the "Backup Load" is serviced when the inverter is disconnected from the grid.  This is especially handy when there are  regular grid failures so that you are not flattening your battery running "non-essential loads" from the battery at night.  

There is also a Smart Load connection option which will only send power to the loads from the inverter when specified levels of battery level are reached (have never used this so maybe someone else can comment if I am missing anything)

 

 

 

Thanks for the replys guys!

@Sc00bs So to clarify, the "zero export power" value is actually a small amount of power we intentionally take from the grid at all times to ensure the meter won't trip when we are not allowed to export/feedback energy back to the grid? Did I understand that right? If so, I'm guessing the reason has to do with the meter's tolerance around what the "zero point" is. Also, if this is the case, then for a value of 20W it'd mean a daily grid consumption of 480 Wh or monthly 14.4 kWh even if we have batteries just so we keep the meter happy? Is this the "cost of doing business" so to speak? In that case I'll certainly want that set to 0.

 

Thanks for the replys guys!

@Sc00bs So to clarify, the "zero export power" value is actually a small amount of power we intentionally take from the grid at all times to ensure the meter won't trip when we are not allowed to export/feedback energy back to the grid? Did I understand that right? If so, I'm guessing the reason has to do with the meter's tolerance around what the "zero point" is. Also, if this is the case, then for a value of 20W it'd mean a daily grid consumption of 480 Wh or monthly 14.4 kWh even if we have batteries just so we keep the meter happy? Is this the "cost of doing business" so to speak? In that case I'll certainly want that set to 0.

Setting it to zero will most likely cause a trip of the meter. The inverter cannot pre-empt the geyser that is on and switches off. All control systems can only react on what they measure and there is a delay to adjust. 

The 20W used at all times is there for this reaction time in simple speak. In the same way some meters will trip seeing export as tamper in a flash and others are set to look af the magnitude/time based value before reacting. 

I see. So it sounds like I understood correctly. 

However, in my case, as I want to be a prosumer and will have an arrangement with the utility company to sell them energy as well as a special bidirectional meter, as you pointed out in Sc00bs reply, setting it to 0 in this instance would not be a problem. I wonder if the value even matters at all. I mean it sounds like I'd save some money at night by not pulling 20W from the grid.

Edited September 26, 20232 yr by ultrasbz

 

Thanks for the replys guys!

@Sc00bs So to clarify, the "zero export power" value is actually a small amount of power we intentionally take from the grid at all times to ensure the meter won't trip when we are not allowed to export/feedback energy back to the grid? Did I understand that right? If so, I'm guessing the reason has to do with the meter's tolerance around what the "zero point" is. Also, if this is the case, then for a value of 20W it'd mean a daily grid consumption of 480 Wh or monthly 14.4 kWh even if we have batteries just so we keep the meter happy? Is this the "cost of doing business" so to speak? In that case I'll certainly want that set to 0.

100% correct, that is my understanding in any case 🙂 

I disconnect my grid during the day so as not to be using any grid power unnecessarily. 

 

 

Setting it to zero will most likely cause a trip of the meter. The inverter cannot pre-empt the geyser that is on and switches off. All control systems can only react on what they measure and there is a delay to adjust. 

The 20W used at all times is there for this reaction time in simple speak. In the same way some meters will trip seeing export as tamper in a flash and others are set to look af the magnitude/time based value before reacting. 

@ultrasbzwas talking about feeding back excess power into the grid, as such I assume that he is not in South Africa and is able to do so without any issues. Sending a bit of power into the grid when the geyser switches off would not be an issue. 

 

However, after reading the manual and forums as well as watching a lot of youtube videos it is still unclear to me if priorities can be set up such that:
1) if solar is available use that first
2) if no solar (night), then use only batteries (until a low threshold is reached)
3) only as a last resource use the grid
4) in all cases, excess solar should be exported to grid
5) never use grid to charge batteries

 

All of the above are possible to set in the Deye, and then some.

As for the comment below about point 4, it is possible to set your battery to export to the grid if  you choose the mode "Selling First" and use it in conjunction with the the "Time of Use" timer settings. If you don't want this, use "Zero Export to Load(or CT)" with Solar Sell box ticked. You'll sell solar power, but no battery power..

 

1 - yes

2 - yes

3 - Yes, but why? The grid is effectively a battery from which you can draw as required, when Sun + battery is not enough.

4 - Not sure, because at night your battery will also export its charge to grid if there is no solar. Youd need a switch to tell the inverter not to export at night???

5 - Yes..

 

 

I also see that Deye supports "non-essential loads" circuit that requires a CT as well as an "essential loads" circuit where the loads get connected through the inverter.
It is my understanding (correct me if I'm wrong) that the non-essential side would still consume at least a small amount of grid energy even if it is set to last priority as it would be necessary for the CT to record such a consumption before the inverter would adapt to force only solar/battery energy usage. In this case, am I right in saying that if I want truly 0 grid consumption I should just connect all loads (house, everything) to the "essential loads" circuit and just non bother with the "non-essentials" at all?

I would still suggest putting your larger loads on non-essential loads, because then you can supply to all loads in the house up to the maximum load capacity of the house, for example a 63A circuit breaker, blending grid and solar power. If you put all on essential loads, you are limited to the pass-through current that the inverter allows. I'd say not to be tempted to exclude the fitment of the CT coil.

Maybe you've got it the wrong way around regarding the power flow before adapting to force zero usage. The point is to zero the current that is flowing out of the house, not inwards, in other words, if your solar can generate 5kW duing the day, or for the matter the battery can supply 5kW at night, but your load is 4kW, then it will scale back the production to just what you need. You can in any case reduce the Zero-export value to 0 if you'll be exporting to the grid, and so save on the consistent small draw.

In a hybrid grid-tied system like this I think you need to make peace with frequently trading some amounts of power, either for short transient periods as your load level changes, or otherwise for longer bouts of bad weather.

Thank you so much for the help, everyone!

Just a few more things to clarify:

1) Regarding the low battery threshold that would make the inverter switch to grid. Do you set it as a voltage or a percentage of the SoC? I know voltages can be problematic for LiFePO4 due to the flat discharge curve where 30% and 80% can be about the same voltage. On the other hand, for SoC percentages you need to have communication between the inverter and battery BMS, and I've heard that even popular BMS's like the JK BMS isn't always very accurate and can suffer from drift. It seems that in terms of SoC the consensus is the Victron Smart Shunt is the best but then I don't think it can be connected to the Deye to let it know the SoC. What is your setup in this regard?

2) Let's suppose the max power I can take from the grid is 5 kW (contract limitation) and my inverter is 5 kW Deye so maximum I could use on the "essentials circuit" is 5 kW. Does this mean that it possible to use on the "non-essentials circuit" a load as high as 10 kW where the power would be combined as the max 5 kW from the grid + supplemented by the inverter with the max 5 kW from solar/batteries?

 

Thank you so much for the help, everyone!

Just a few more things to clarify:

1) Regarding the low battery threshold that would make the inverter switch to grid. Do you set it as a voltage or a percentage of the SoC? I know voltages can be problematic for LiFePO4 due to the flat discharge curve where 30% and 80% can be about the same voltage. On the other hand, for SoC percentages you need to have communication between the inverter and battery BMS, and I've heard that even popular BMS's like the JK BMS isn't always very accurate and can suffer from drift. It seems that in terms of SoC the consensus is the Victron Smart Shunt is the best but then I don't think it can be connected to the Deye to let it know the SoC. What is your setup in this regard?

2) Let's suppose the max power I can take from the grid is 5 kW (contract limitation) and my inverter is 5 kW Deye so maximum I could use on the "essentials circuit" is 5 kW. Does this mean that it possible to use on the "non-essentials circuit" a load as high as 10 kW where the power would be combined as the max 5 kW from the grid + supplemented by the inverter with the max 5 kW from solar/batteries?

1. Personally I use the SOC as provided to the inverter by the BMS built into the battery. If it's not accurate and something is damaged, I believe I should have recourse from the manufacturer, but so far I've had no issues.

 

2. The max power on the essentials circuited is limited by the pass-through current of the inverter to the essential loads, in this case I think AC 32A, or around 7.5kW at 230V.

Of that 7.5kW, up to 5kW can be supplied by the inverter from solar/battery, and the balance can be drawn from the grid.

 

What you say about the load on the non-essentials circuit being up to 10kW sounds right, but I've never personally used it like that. Here you would set the Grid Peak Shaving power to 5000W as in the image above, and use the "Zero Export to CT" working mode to export up to 5kW from the battery/solar. This is on the understanding that the grid is available, and the Voltage and frequency parameters are within the limits set.

I know this is an old topic, but I am trying to understand this as well. I have a 16kW Deye inverter with everything in my house connected to the "essentials"/UPS. I have enough batteries to not require any current from the utility and in South Africa it does not make any financial sense to feed back.
I operate most of the time with the grid disconnected, but the municipality now wants to install a prepaid meter. I am not sure I understand the need to draw 20W continuously. My understanding is that the "essentials"/UPS power gets regulated/supplied by the inverter from the solar panel and batteries, there should be no feed-through. I can understand if I have loads on non-essentials that switching can cause feed-back, but I do not understand why a load on "essentials" will require this. Even if my oven or geyser or pool pump switches on or off, this is supplied through the inverter directly, not through the inverter in parallel with the utility.
Can somebody explain. Maybe there is something I do not understand. WIth my current old style electricity meter, the meter has not registered any electricity usage for 2 months, even though the inverter reports drawing 20 W periodically from the grid.

Edited November 10, 2025Nov 10 by Freek Eek

2 hours ago, Freek Eek said:

I know this is an old topic, but I am trying to understand this as well. I have a 16kW Deye inverter with everything in my house connected to the "essentials"/UPS. I have enough batteries to not require any current from the utility and in South Africa it does not make any financial sense to feed back.
I operate most of the time with the grid disconnected, but the municipality now wants to install a prepaid meter. I am not sure I understand the need to draw 20W continuously. My understanding is that the "essentials"/UPS power gets regulated/supplied by the inverter from the solar panel and batteries, there should be no feed-through. I can understand if I have loads on non-essentials that switching can cause feed-back, but I do not understand why a load on "essentials" will require this. Even if my oven or geyser or pool pump switches on or off, this is supplied through the inverter directly, not through the inverter in parallel with the utility.
Can somebody explain. Maybe there is something I do not understand. WIth my current old style electricity meter, the meter has not registered any electricity usage for 2 months, even though the inverter reports drawing 20 W periodically from the grid.

As the grid input is also the grid feed back. Your settings have to be correct to limit feed back when you have the prepaid meter. The most important settings are Zero export to CT and also unstick solar selling. You can use the always draw 20 to 50W from grid but if your grid is off then no power can be drawn or exported to the grid. You can use a smart switch to switch the grid on or off via the phone APP.

This is how I use my smaller Deye inverter. Grid off about 98% of the time. Only with low PV I might ensure the battery is not discharged too low would I use a few hours in the early mornings if the previous day had low PV for fully charging. Normally batteries are fully charged at around 12h or earlier. SOC can be as high as 50% if low loads were on during the evening. Mostly cooking.

@Freek Eek ,

The 20W draw is not continuous, but varies in duration, depending on the time of day (or night, to be precise). Refer to my grid graph, you will clearly see that when Solar is not present, the inverter almost continuously draws 20W. During daytime, it rarely draws this, but still does it very infrequently. Hope this helps. All these draws per day don't even register as 0.1 of a kWh, which is the smallest fraction my system can record.

In my mind, another reason for this draw, is to keep the inverter synced to the grid, because our ZA grid is definitely not @ 50Hz. Far from it.