bobah1248

@kuba.cz Thank you very much! What you wrote coincides with my observations (plus or minus the measurement error of the inverter itself) My inverter says that the ZZ parameter is 01, i.e. Germany. In other words, this is already the lowest possible level 😥

I'm glad I got the point across. 😄

This can be checked in simpler and less dangerous ways. For example, measure the voltage using AC voltmeter between the L terminals of the inverter input and output (then between N terminals) - if it is about a couple of volts or lower, then the bypass relay is closed. Another way is to switch parameter 03 ("AC input voltage range") from APL mode (90-280VAC) to UPS mode (170-280VAC), then wait until the voltage in the network drops below 170V (this happens to me on one phase every day) and look at the bypass icons, input and output voltage, you can measure with a voltmeter as in the previous case. Any way, I checked both of them and can say - if bypass icon present on inverters display, the grid relay and load relay are closed. Uploading Attachment...

@Youda In my inverter selial interface command QPIGS (Device general status parameters) has valid parameters: Y Solar feed to grid status (reserved feature) 0: normal 1: solar feed to grid ZZ Set country customized regulation (reserved feature) 00: India 01: Germany 02: South America AAAA Solar feed to grid power (reserved feature) A is an Integer ranging from 0 to 9. The units is W. I believe that it is under the ZZ group that all the settings for exporting to the power grid are hidden

I am 90% sure that it is shorted for the following reasons: the output voltage is equal to the input voltage to the inverter the screen shows the "bypass" icon The only difference is that the inverter pumps in as much solar energy as the household consumers need (according to its output ammeter). At the same time, the input ammeter shows fractions of an ampere, which means no export (and import, if there is enough solar energy) In any case, forcing the relay to close is a very bad idea: it explodes IGBT transistors, burns IGBT drivers and even control transformers inside the inverter ☹️

I agree. When my inverters burned out, I thought a couple of times how I could implement the inverter control program myself. But it seemed like a colossal amount of work that would take about six months. In any case, before trying to cheat the firmware, I turned to this forum to understand what consequences could await me, in addition to understated readings and generation of undervoltage when working without a grid (according to my calculations, when setting 220V, the inverter in offline mode will produce almost 209V; and this is just the tip of the iceberg that i can see now). I also thought that instead of constantly overvolting, I could temporarily connect resistors. This is like a kickstarter for hysteresis - inverters turn off export when the voltage is below 175V, and turn on again when the voltage is above 195V or so. This would allow me to restore export when the voltage temporarily dropped below 175V, but then returned to 185V. And because of hysteresis, export does not resume. Thus, I could push the inverter to resume export, fooling not the entire inverter, but only a part of it and for a very short time (connect a "patch" resistors for a few seconds)

@Youda Yes, this service manual is aplicable But my inverter is missing several minor modules: SCR Board PV EMI Board REMOTE & WIFI Board AC breaker The inverter's appearance and controls look 100% the same. The "1.2. Basic topology introduction" diagram, cross wiring PCBs, fault and warning codes are same.

Thanks a lot - I have the same vision for AC input and output, as well as HVBUS does not affect when the AC output voltage is lower than the HVBUS Yes, I have seen threads on this forum where this was worked out in great detail and appropriate conclusions were made. Anyway, thank you very much for mentioning this point. I agree with you 100%. This is exactly what I tell my friends who complain about the energy supply company, but at the same time do not want to limit their electricity consumption to improve the situation ☹️ This has already been done - I am literally 15 meters from the grid transformer, I laid short but thick cables to the power grid, I distributed the export so as to somehow balance the voltage on the phases of the power grid. But the power of the power grid transformer does not correspond to the all-season load. It would be better not to torture my inverters, but to wait until the grid transformer burns out and the power supply company replaces it with a more powerful one 😈😈😈

@Coulomb Thank you very much for your feedback. In fact, I was only worried about one thing: let's say I change the voltage measurement characteristics at the AC input to +10V. Then I turn on the export, the inverter will close the bypass. And then the inverter will see that at the AC input, say, 190V (real 180V + 10V my virtual bonus), and the inverter AC output sees the real 180V. If I were the inverter, I would be confused, then decide that the inverter is faulty and refuse to work. The same applies to the internal high-voltage HVBUS bus, from which the "sine wave drawing" occurs, as well as battery charging/disharging. That is, I think it may not be enough to simply change the resistors at the AC input - I also will have to change resistors at the AC output, then possibly on HVBUS, and this in turn will require redoing the same on the MPPT sensors and possibly even the battery charger. In principle, it was this chain of probable events that made me write my question on this forum. It is possible that I am simply exaggerating and the firmware in my inverter does not care about the listed inconsistencies. But, since you have never encountered anything like this, I will have to be extremely careful if I decide to do such a rework sometime in the future. Thanks a lot!

@Beat Unfortunately, my percentage calculations are correct. Although the accuracy of measuring the electrical characteristics of inverters leaves much to be desired, the inverter shows exactly 80% efficiency when reading data via the serial interface. I also correctly calculated 20% from 6 kW (from the input power), and not from the 4.8 kW (where the efficiency has already been recalculated). Regarding the declared efficiency of inverters by the manufacturer, you most likely saw the "Peak Efficienty" parameter. That's right - in ideal conditions (for my inverter, air temperature 20-25'C, humidity 30-80%, voltage at the MPPT input 380VDC, resistive load that not more than 80% of maximal power inverter), inverters are really capable of delivering an efficiency of up to 93% and may be even for several minutes. But as soon as the voltage on the MPPT drops, the temperature on the transistors and inductors rises, and the efficiency begins to fall rapidly. And at this point, you need to focus on the "Rated Efficienty" parameter, which is not declared by all manufacturers (too many dependencies, even the region of usage affects the efficiency) In any case, "Rated Efficienty" usually does not fall below 75% (again, in ideal conditions for air) and this is taking into account the full chain of DC-AC conversion. Anyway, thanks for your thoughts and calculations.

@HennieL Thank you very much for the link. As I wrote above, I installed a powerful industrial fan that ventilates the air well (sucks in from outside the house). Since my inverters have radiators inside, I additionally installed a computer fan on the problem inverter so that it would forcibly remove air from the inside. And yes, it works, but for now the outside air temperature is below 35'C. But now the outside air temperature in the shade is on average 42'C and this continues every year for about 60 days. I think I just need to put up with these abnormal two months (the first one already left) and not overheat the inverters because of electricity export. Especially since the components for repairing inverters are very expensive (and if the electrolytic capacitors will dry out due to the overheating, then they will have to be ordered from China or Russia, and wait for delivery for about a month)

@HennieL Thank you for suggestions. Regarding the direction of the blowing of the built-in fans - I have installed separators inside the case for now and broken the closed loop, additionally installed a computer fan to blow air out of the inverter from the top. But, as it turned out, computer fans are too weak - their power is less than 200 mA (at 12 V). I found more powerful fans of a suitable size on Aliexpress, with a power of 1-2 A (at 12 V). And bought one to try, but it turned out that they have a power of only 0.8 A (at 12 V), although according to the anemometer, the air flow is about 1.5 times more powerful than the computer one. In general, I see 3 options at once - either liquid cooling, or make holes in the inverter and add dust protection and additional fans, or buy the right inverters ;) Regarding the Peltier elements - I have them and I even tried to play with them (air and liquid cooling). But their value is, to put it mildly, exaggerated. Let's do some calculations: I measured the efficiency of the inverters, and it is about 75-80%, which is not bad in general Each inverter in hot weather can receive about 6 kW from solar panels, and give out 4.8 kW to the grid (at 80% efficiency) Thus, each inverter converts 6 kW minus 4.8 kW is 1.2 kW of energy into heat. Moreover, these 1.2 kW have 100% efficiency I have 2 inverters, which means I have a powerful electric grill with a total power of 2.4 kW 😂😂😂 Each Peltier element consumes about 1.5 A, which means its power is only about 18 W Thus, to remove 2.4 kW of heat, we need to spend about the same power Then 2.4 kW divided by 18 W, we get that we need at least 133 Peltier elements, provided that they are 100% efficient, which is not the case (or at least 66 for each inverter) It is simply impossible to install so many elements directly into each inverter 🥲 But, of course, the idea was good - it is similar to idea @Beat installing an air conditioner, which will try to spend about 3 kW of electricity to get rid of 2.4 kW of heat. It is for this reason that I had an idea about heating water for household needs - i.e. I would spend these free 2.4 kWh of heat on what I am already forced to spend every day 😀

@Youda Thank you very much for your detailed answer! Offtop: To be honest, I chose inverters from what was on our market. In the process of choosing, it turned out that our local sellers simply resell what is illegally imported from China. Unfortunately, we still do not have dealerships or service centers that could give an answer at least somewhat similar to yours. For example, I had to assemble a cable for connecting the BMS to the inverter myself, as well as make settings for the BMS and inverters. In general. I think you now have an idea of the level of local sellers. As a result, I chose between Voltronic and Deya, without the opportunity to see and compare their work in any showroom. In the end, I managed to find a way to buy 2 inverters and a battery directly from China. However, I was only able to find copies of Voltronic at a reasonable price (but I found out later that they were copies). Let's get back to your recommendations: my inverters are budget ones and they seem to have everything (including export), but this is mostly added "just in case", and not for the intended use (in principle, I discovered this myself after purchasing them) it turns out that judging by your picture, the best hybrid inverter looks like the inverters from Deya due to the possibility of flexible settings and responsive service I need to cool the inverters forcibly with a large volume of air - this is exactly how I have it now: in the room there are only protective grilles that do not allow it to heat up from sun, an industrial fan of more than 200 W is installed. To make the cooling even better - this is only removing the front protective panel of the inverters, allowing the industrial fan to blow directly on the radiators, transformers and inductors. But this creates the danger of large amounts of dust and conductive particles getting into it regarding liquid cooling - everything is exactly as you said: I live in a private house, I have storage tanks for hot water. In addition, water is relatively cheap here, and I can heat the pool or simply turn it into fog (using a microclimate system) - it is very hot here in the summer, low humidity and a lot of dust therefore, liquid cooling would allow to reduce the temperature on the radiators by approximately 2 times, compared to air (+40'C air temperature will be worse than +15'C water temperature) as an option, for cooling, you can assemble a heat pump that would not use liquid, it would allow you to safely heat the water in the storage to 70'C, while cooling the radiators to 35-50'C, but this is a completely different story and research I completely agree - properly designed and assembled equipment is a guarantee of safety for both the equipment and the home, including its residents. Therefore, thoughtless conversion of radiators to liquid is not acceptable (for example, to computer, which successfully works with equipment worth several thousand USD). And first of all, because the solar power plant works not only with high voltage, but also completely autonomously (without direct supervision of people, as is done with a PC) I had to repair inverters and in the process, I discovered that the cooling in the my inverters is assembled a little strangely: one fan (MPPT) blows from the bottom into the inverter and the other two (220VAC and Battery) blow the opposite way - from the inside to down i.e. in fact, the air inside my inverters is looped!!! I added several fans, which slightly improved the overall situation, but it worked well while the air temperature was no more than +35'C If you are interested, here is the story of my inverters and the overly high voltage of 6 kV

Central Asia, Uzbekistan Yesterday the air temperature was +46'C 😅 And today it was cool +40'C 😉

@Bobster. The basic behavior of the inverters is 100% consistent with the paper user manual. Export to the power grid is very similar to the USb mode (see 01 Output source priority) - in this mode, the inverter operates in bypass mode, but adds to this grid voltage as much current from the panels as is required in the load. Thus, the voltage in the house is equal to the voltage in the power grid. There is another parameter "03 AC input voltage range", which forces to completely disconnect from the power grid and switch to the inverter with an exact voltage value of 220V (or 230V, as in your case). That is, if I set the UPS mode, then disconnection from the power grid will occur if there is less than 170V. But if set it to APL and then the inverter will continue to maintain the connection even down to 90V. When the export mode is enabled, the inverter stops limiting the current consumption and it begins to flow into the grid through this open bypass. From this point of view, it seems strange why the export stops at 170V, although parameter 03 still allows supplying down to 90V to the house and, moreover, the admixture from solar panels occurs normally. I.e. the limitation on the admixture of solar energy is simply re-enabled (I can clearly see this in the status when requesting QFLAG and QPIGS from the inverter via com-port). This point surprises me very much, and if my vision of the inverter operation in export mode is correct, then I am inclined to think that there must be firmware or an inverter for which the limitation is not restored to a fixed value of approximately 185V-170V. In addition, I have the impression that this threshold is adjustable and is stored in the EEPROM chip. And, with due skills, this value can be adjusted directly in the EEPROM chip or by command via the serial interface (possibly the display serial interface, but not the one that comes out on the connector on the front of panel)