ES-Mini comes in two variants.
1) ES-Mini-2000
Panels
The solution consists of solar panels which can produce up to 3000Wp and which do not exceed 500V voltage when connected in series. This could be six (minimum: four) modern 450W or even 500W panels. It could also be 9 or 10 older panels (e.g. 320W each).
Inverter
The inverter MIC-2000TL-X is a classical string inverter with only one power point tracker. It is very cheap (probably ~140€). For configuration and monitoring one must add a Shine-Link-X WIFI stick (15€).
If you connect the inverter to the string of panels and to your home grid (single phase, 16A) you will have a solution which simply feeds all of the solar energy it can harvest into your local home grid.
If you add a smart meter you can control the amount of backfeed into the grid.
Here is a link to the manual for the inverter and for the shine link wifi stick
Installation material
You will need an AC cable and two DC cables with 4 MC4 connectors.
We recommend to mount the inverter inside the building which means that you need only two long DC wires (e.g. 15m) and the AC wire will be short.
But it is also possible to place the inverter outside close to the panels which would mean that you have no additional DC cable but a longer AC cable.
If you install a smart meter the cable from the grid connection box would have to go outside on the roof as well.
You need mounting material for the panels depending on your roof’s conditions. Keep in mind that you should avoid a situation where shadows of trees or other buildings move over the panel surface. A low angle (10 degrees or so) with half of the panels facing East and the other half facing West will spread the energy flow over the day more evenly. For maximum power gain you could use a steeper angle and southern orientation. But depending on how much energy you need (and when you need it) this may lead to excess energy wich you (hopefully) can feed into the official grid (probably without financial compensation). A southern orientation and an angle of 25 degrees may make sense if you add a backup storage solution (UPS) to your system. If your roof angle is around 20 degrees using both East and West side could be problematic because there will be shadow on one of two times almost always. Which means that the overall efficiency will not be very good because the panels are connected in series. In such cases an inverter with 2 MPPTs would be the better solution (Growatt MIN 2500).
Backup Solution (UPS)
A UPS solution like the Fossibot F1200 (400€ with voucher) helps you to bridge periods where the public grid is not available. It has the additional advantage that it is portable. It can be placed anywhere in your house, typically close to the devices for which you want to provide emergency power in case of grid failure.
The primary focus of such a system is protection against fault. This means that it is connected to the grid permanently and it will discharge its battery only if the grid power goes away. The switching process is automatic and happens within 10 milliseconds.
Here is a link to the Fossibot manual.
An additional use case, however, is to discharge the battery when the sunlight disappears. This will optimize your energy cost because the battery can get charged form sunlight for free during daytime. We offer a mechanism to discharge the UPS battery during night while keeping a minimum between 15% and 30% (recharging to 30% from the grid if the battery falls below 15%).
A good idea would be to use the electric power of your UPS system for your fridge and for other devices which need energy permanently (like pumps of your heating). You can also connect your TV. The maximum output is around 1000 Watts.
This is achieved by two “Shelly Plug S Plus” which track the energy flowing into the battery and out of it. You need to install two scripts on these plugs which we provide via github. The first script reports its local IP to a registry. It must be installed on both shelly devices and is needed so that they can communicate to each other. The second script must only be installed on the shelly which sits at the input side of the UPS. It decides when the battery is allowed to charge and when not. All your AC output must go through the Shelly on the Outlet side, so you should use only one of the two AC connectors available on the Fossibot UPS.
Smart Meter
A smart meter like the SDM630 (60€) or the DTSU666 can be installed in your grid box if you are required to avoid feeding energy back into the grid. The smart meter must be connected via a thin RS485 cable to the inverter.
Here is a link to the SDM 630 manual and to the DTSU 666 manual.
If you must control backfeed a smart meter is necessary. Otherwise not.
In Ukraine most households have a master switch in the grid box, sitting next to the officicial energy meter. This makes it fairly easy to install a smart meter because you can switch off electric power completely during the installation of the smart meter. Of course you must really know what you are doing if you are attempting to change something within your grid fuse box. Otherwise you must find someone who knows how to do it and who works on a professional level with electricity.
Phase Equalization
There is another point which is important when considering backflow resp. the use of your own energy: PHASE assignment of source and drain. You have three AC phases in your house (with a phase shift of 120° between them) and the electric loads are connected more or less randomly to one of the three phases. If you connect a PV system to phase 1 and if your loads take the same amount of energy from phase 3 (for example) then the NET BALANCE of your household will be ZERO. But technically speaking the electric current on phase 1 will flow into the grid and a flow of equal size will be imported on phase 3. Typically the energy meter of your provider calculates the sum of the energy flows over all three phases and the number it shows reflects the SUM of the three flows.
Therefore it is not necessary to connect the ES-system to a specific phase.
Should you really have a meter which does no balance out phase differences when calculating energy consumption phase assigment would be an issue. In case of doubt ask an electrician or your grid provider.
Reading SML signals via infrared
If you have a modern bi-directional smart meter chances are good that it has an infrared LED which permanently sends metering data via a protocol called SML. Sometimes you must enable this feature via a PIN which you can get from your grid provider. If you have such a meter you can apply a small device which picks up the infrared signals, the SML reader. This device costs around 40€; it has WIFI and comes with a software (TASMOTA) which allows it to send the metering data via MQTT to a server or to respond to HTTP requests in JSON format. The SML reader can also transfer its data to a web host like ThingSpeak when configured to do so.
See this video to learn how the metering data can be uploaded to a cloud account at ThingSpeak. Using the BitShake TASMOTA device you would need a Script like the following. Note, however, that the lines in the >M section will differ depending on the model of your energy meter
>D
>B
->sensor53 r
>S
if upsecs%60==0
then
->WebSend [api.thingspeak.com] /update?api_key=yourAPIkey&field1=%sml[1]%&field2=%sml[2]%&field3=%sml[3]%
endif
>M 1
+1,5,s,0,9600,ED300L,4
1,=so1,00010800,63,5,63,5,000f0700
1,=soC,1024,0
1,77070100010800ff@1000,Bezug,kWh,E_in,3
1,77070100020800ff@1000,Einspeisung,kWh,E_out,3
1,77070100100700ff@1,akt. Leistung,W,Power,0
#To control the inverter based on this data you need to have another piece of hardware and software: A Raspberry PI running Homeassistant, MQTT and NODE-RED. You would have to set up some scripts in Node Red which ask the SML reader for the current energy needs and then talk to the inverter to adjust the maximum amount of energy it may produce at the moment. This process must repeat every 5 or 10 seconds automatically. In the end the inverter of your PV system will restrict its power production to a value which guarantees that a definable threshold a backflow is not exceeded.
The sequence of steps is as follows:
- it starts with the electrical current flowing between your house and the grid
- the official grid meter with infrared LED measures the current
- the meter sends infrared signals using the SML protocol
- the SML reader with WIFI and TASMOTA recognizes this signal
- the SML reader produces WIFI messages with MQTT data or repsonses to HTTP requests from HOMEASSISTANT
- The MQTT database on a HA (HOMEASSISTANT) server stores that data
- A NODERED system on the same server picks up the messages
- the HA must have an integration for the Growatt inverter
- A special NODERED script picks up the SML messages via MQTT or periodically requests SML data from the SML reader via HTTP and then tells the inverter how much energy it is allowed to produce
- The whole chain of commands runs every 10 seconds or so. The NODERED script will change the inverter setting only if there is a significant change in grid import/export data
Compared to installing a physical smart meter in your grid box this approach does not need an electrician and it is totally safe. But it costs more and needs significant software skills. The Raspberry PI4 with 4GB will cost ~100€, so that you will have to spend ~ 140€ in total plus some hours of installation work to get this solution going.
If you have good software skills or know someone who has these skills and will help you this may be a good way to proceed. Without a good affinity to home control software we do not recommend this kind of solution.
Advantages and Disadvantages of ES-Mini-2000
Advantages:
simple DC cabling (serial connection), voltages not too high (150..200V)
2000W AC output for many hours, because six panels will deliver a lot of DC energy even under moderate sunlight conditions
Simple AC installation (connect to 220V single phase)
Flexible location: device is IP65 protected, can be placed outside or inside the building.
For only 80€ you can control the maximum amount of energy which the system feeds back into the grid.
For additional 400€ you get a USV battery with 1 kWh usable energy. This can supply energy to critical devices for several hours.
Disadvantages
The panels must have free access to the sky (no shading or you will get significantly less energy)
Installing a smart meter requires work inside the grid connection box (as is always the case if you need to control the amount of energy backflow)
You must care for charging the USV system via selecting the charge rate and time schedule manually
You must connect the critical load devices (laptop, router, radio, tv, chargers for mobile devices, fridge, etc.) to the power outlet of the USV.
2) ES-Mini-800B (with Backup )
ES-Mini-800 comes with an integrated 2kWh battery and has a power socket for offline use.
Panels
The solution consists of four solar panels which can produce up to 1800Wp.
Inverter and Battery
Smart Meter
A smart meter Shelly EM3 pro should be installed in your grid box so that the inverter knows your energy consumption and can use excess energy for battery charge and adapt discharge to your current needs.
Without a smart meter you will have to create a schedule which defines when the inverter and/or battery deliver how much energy to your local grid (the remainder goes into the battery until it is full). For instance you may define a delivery of 150W during night and 800W during day. But this is only a rough guess and it will lead to situations where you buy energy from your provider although it would not be necessary.
Advantages and Disadvantages of ES-Mini-800B
Advantages:
Low DC voltages (< 60V)
Partial / temporary shading is not harmful (the system has 4 MPPTs)
1800W DC will be able to deliver 800W AC even under moderate sunlight conditions
Simple AC installation (connect to 220V single phase)
Relatively large battery capacity of 2 kWh (can even be extended)
The battery works automatically (if a smart meter is installed)
Grid feeding can be configured or limited (with smart meter installed)
Disadvantages
There is only a maximum of 800W AC available.
long DC cables: Each panel must be individually connected to the inverter.
The inverter/battery (~ 30kg weight) must be placed inside the house near a place where you can connect the backup power socket to your critical devices.
Installing a smart meter is highly recommended but needs work inside the grid connection box
You must connect the critical devices (laptop, router, radio, tv, chargers for mobile devices, fridge, etc.) to the power outlet of the inverter/battery.
The system does not provide battery energy for all devices in your house.