Deye Hybrid Inverter Review - Off-grid [Sunsynk, Sol-Ark]

[Jlemos_Silva]

@Svarky Thanks for your answer. I got that point. May be I did not put my ideas clearly. Sorry about that.

I asked that question, because you wrote:

“… It has been running high loads such as air-conditioners (Split-systems) and water pumps without any problems up to 8kW peak loads…”

I would greatly appreciate it, if you could provide me with the information: How long the battery bank designed by you, withstand the combination of your Air-conditioner (nominal Power?) + your water pump (nominal power?), in continuous utilization?

PS.: Forgive my lack of understanding. I am a newcomer in the solar world.

Best Regards

[Svarky]

@Jlemos_Silva, ok. The 8kW load I mentioned was a peak load for a very short amount of time. This is not a continuous load.
The average continuous loads are closer to 2.5kW, so it can easily power these loads for many hours.

If you want to understand the total power consumption for your own needs, then you will need to use an off-grid load calculator to determine the average daily consumption (kWh) and your high continuous loads (maximum demand). This will help you determine what size battery bank you need for your application.

[Jase_Admin]

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[Njmorin1]

My generator is auto starting and ramps up nicely to 6kw charge for a while. Then it keeps running but just stops charging the batteries. I don’t yet have that custom canbus cable and hopefully that will fix the problem. We are fully off grid on an island and I really need the generator top up when the ice is too thin for travel and we have a few days of cloud.
We have 6.2kw panels, and two volthium 10kw lithium batteries.

[Jase_Admin]

@Njmorin1, I am not familiar with Volthium batteries. Do they need to be connected via Canbus to operate? Please create a new post about your particular issue with the Volthium battery. Thanks

[Feenster]

Hello Svarky. I have always gone with the All-in-one option as I need to be able to charge up my batteries with a generator during the winter months (as I am off-grid). Is there a way around this? In other words is there the option of a stand alone inverter that can also charge from generator?
How is the generator interacting with the inverter at this stage? I note that you had some difficulty with it at the beginning that you successfully overcame. Have you had any issues since then?
Some inverters come with the neutral and ground bonded inside the unit itself (which can be undone if need be). Is the neutral and ground bonded in the Deye, and if not, how have you dealt with the issue?
Thank you.

[Svarky]

@Feenster, by an all-in-one inverter, I am referring to an inverter with solar (MPPTs) integrated with the battery inverter-charger (much like a hybrid inverter).

Most off-grid inverters are inverters with integrated chargers. Technically, they allow bi-directional (two-way) power flow - discharging and charging on the DC side. This article explains more about off-grid inverter-chargers

The bi-directional function also works on the AC side, allowing the inverter to work as a hybrid inverter to export power to the grid. When connected to a generator (off-grid), the inverter synchronises with the AC source to feed the AC loads and charge the batteries. I haven’t had any issues with this since I found the correct settings.

Earth-Neutral link - The ground (earth) and neutral are not linked in the Deye inverters (sold in Australia). This might be different for Deye inverters sold in other countries though.

[Feenster]

Thanks for that.
How do you take care of your neutral ground bond? Have you taken care of it in the distribution box (fuse board)?
I am thinking of getting this Deye Inverter after Christmas. I will follow your review with interest.

[Svarky]

In Australia, the neutral-to-ground bond (referred to as the Main Earth-Neutral or MEN link) must be located in the main switchboard. This is a legal requirement. Any connected AC sources, such as an inverter or backup generator, must have the MEN link removed (if they have one installed).

[Matthew]

Jason,

Multiple Earth Neutral** not Main Earth Neutral.

These units are to be CEC approved 1st QTR 24 I believe, available exclusively from Master Instruments.

[mgu]

Does anyone know how the Deye inverter reacts if the max Vmpp is exceeded?

Eg 7-8 bifacial modules in one row will have a voltage from (hottest) 286V to (coldest) 440V
This is 15V more than the 125-425Vmpp range in the sheet.

Would such a setup damage the inverter, or only reduce its efficiency or cause a safety shutdown?

As the specs also say PV Input Voltage goes from 125 to max 500 V I assume only the mpp tracking is suboptimal under such extreme conditions (-5° C) but the inverter could handle even 9 panels in a row.

It’s also not clear to me how such min temperatures needs to be considered. Usually the daily lowest temperature is during night times. And on nights even below -5° C the days too production phase will be 5-10 degrees warmer.

Do I miss something here?

[Svarky]

Exceeding the MPPT operating voltage will likely ramp down the output to a very low level. It is very unlikely that it would damage the inverter or cause any errors. I have never heard of an inverter being damaged by exceeding the MPPT operating voltage range.

Minimum temperatures usually occur in the early morning (frosty) when the sun is rising, so this must be considered when designing a system. Exceeding the Voc limit (500V) will damage the inverter.

[mgu]

@Svarky

but the input current rating is very good at 26A per MPPT, meaning parallel strings is possible on both MPPTs

May you can help me understand this a bit better?

@Svarky

Ics max current is also very high at 39A per MPPT

Assume you mean Isc (not cs) from the datasheet? The 6kW model - I would like to order - has 17A per mpp tracker.

I would start with a first string of 8 modules on one tracker. Then after some structural adaptions add a second string next year.

If the 8 modules are mounted in series, it would look like this.

All Volt, Ampere and Watt values - as best as I understand - should fit into what the inverter can deal with. (Slightly above max mppt v range in very cold weather conditions)

But it seems not possible and useful to think about a 2parallel x 4 modules connected. This would still fit into min startup and mppt voltage thresholds, but the modules then would deliver 13.6 + 13.6 = 27A which is more than the supported 17 for the 6kW model.

Just wonder what the benefits for a parallel arrangement would be? Lower voltage afaik increases the resistance effect of the cables. And adding more than 4 modules wouldn’t make sense as it exceeds the max Watt the inverter can handle .

Next I’m not sure how to expect and understand the string power under different temperature conditions: the 6kW model has 7800W max DC input power.

At min temperatures the string would have ~440V
The module Isc of 13.6A would need to go down if voltage goes up, because the generated power will remain ~ the same at same sunlight power, right?

I see something in the module datasheet, but this seems not enough temperature/voltage effect to me, not?

Last but not least the watt/m² values from the module specs, paired with what watt/m² I can expect at my location over the year

So in cold months with highest string voltages, the max power will be way lower than what the inverter could handle.

Would it make sense, or be possible at all to add (connect) additional modules during cold months? If in series it would clearly exceed the max 500v per string.
But if 2 parallel “substrings” each with 8 modules would have 2x 13.6A this would not fit into the inverter specs.
On the other side, if voltage is such high, the Amperes must be way lower then, right?

Eg at 300w/m² and 21% efficiency this would be max 125W on this 2x1m module. And 1000W on a 8 modules in series string. Would it be 2000w then with 2 series of 8 in parallel?
Assuming a 400V this would mean 2.5A from the single 8 series and 5A from the dual 8 series string.

Sorry for so many theoretical numbers, assumptions and questions.

[Feenster]

Yes, that’s good - probably where I would put it myself. Thanks for the clarification.
What is the maximum charge voltage (for lead acid batteries) on the inverter for user defined settings?

[Feenster]

Svarky, are you still happy with the inverter? I am about to buy one.
I think you mentioned above that you have an old generator? Is it a generator with just average voltage regulation or is it an inverter generator? The reason I ask is that I have a 5 kW diesel generator with AVR and I want to be sure that the inverter won’t have any difficulties with it. Thanks.

[Svarky]

Yes, the Deye inverter has been working well. No problems at all; it actually performs better than expected, even in warm weather (although this summer wasn’t very hot in this southern part of Australia).

I cannot verify if it will work with your old generator. Have you measured the voltage and frequency of your generator while it is operating? Is it stable?
One trick that helps almost any generator to sync with an inverter is to put a load on the generator to stabilise the output. A simple resistive load such as a portable heater or electric kettle works well.

[Hnin]

How can I enable UPS mode?

[Svarky]

Have you read the manual? The inverter should automatically switch to UPS mode when the grid (AC input) is lost. What are you actually trying to achieve, do you want the system to discharge only when the grid is inactive?

There are many settings to enable various work modes.

[Hnin]

My problem is that when the grid is off, the power can’t change quickly. It delays about 5 seconds. That is not okay for some electrical devices. Where can I set up to switch over the power source automatically without delay?

[Svarky]

That is strange. I have only used Deye Hybrid inverters for off-grid systems, so I haven’t had a chance to test the UPS time. Is it always a 5-second delay, or does it vary? Are you using an external CT?

There is a setting on the reconnection time, but I can’t see any setting for switching to backup mode. However, other forums seem to indicate that it is instantaneous.

Also, what grid setting are you using (which country are you in?)