Hi everyone. This is my first post, so I hope it is made on the correct section.

I was able to install my own solar system by trawling the Power Forum, so I want to start by saying thank you to all the contributors to this forum.

I installed my system in August of 2021, so it is almost 2 years old now. It consists of 2 Axpert Kings (5kW each), 5 Pylontech batteries (US3000C) and roughly 12kW of Jinko Solar panels. It is a grid tied system, but without the ability to push electricity back into the grid. The system supplies all our needs and I only need to get electricity from the utility 2% of the time during days of heavy cloud cover and rain.

My observation: I have the ICC system installed on a Raspberry Pi and I've recently noticed that my system is "leaking electricity". The "leak starts at roughly 2kW in the morning and reduces to under 1kW later in the day. The figures on the battery charging/discharging are also corroborated by the additional Victron BMS I have installed. 

My questions: Is this normal or to be expected? If not, where should I start my fault finding process?

Thank you,

André.

43 minutes ago, André3000 said:

Hi everyone. This is my first post, so I hope it is made on the correct section.

I was able to install my own solar system by trawling the Power Forum, so I want to start by saying thank you to all the contributors to this forum.

I installed my system in August of 2021, so it is almost 2 years old now. It consists of 2 Axpert Kings (5kW each), 5 Pylontech batteries (US3000C) and roughly 12kW of Jinko Solar panels. It is a grid tied system, but without the ability to push electricity back into the grid. The system supplies all our needs and I only need to get electricity from the utility 2% of the time during days of heavy cloud cover and rain.

My observation: I have the ICC system installed on a Raspberry Pi and I've recently noticed that my system is "leaking electricity". The "leak starts at roughly 2kW in the morning and reduces to under 1kW later in the day. The figures on the battery charging/discharging are also corroborated by the additional Victron BMS I have installed. 

My questions: Is this normal or to be expected? If not, where should I start my fault finding process?

Thank you,

André.

Well, not sure where the mean the leak is, but what I can see is that your solar is more than what you need, so some of it is lost. Your battery is fully charged at around 13:30, so from then on your solar is only driving loads, the rest is chucked. Is that the "leak" that you are talking about?

The Axperts are known to use a lot of electricity themselves, some people say up to 400W each, so that could also be what you are seeing. I know my Deye inverter chows around 200W around the clock. That is R460 worth of electricity per month just to keep the inverter running...The price of being upper class.

Edited July 7, 20232 yr by HendrikBigChief

Unfortunately, inverters are not 100% efficient.

Thank you HendrikBigChief

The electricity loss/leak occurs while the batteries are charging in the day. So if you look at the first picture you will see that the panels are generating 7811 Watts while the load is 5236 Watts. That should leave 2575 Watts for charging the batteries. The batteries are however only receiving 1671 Watts, which means that the remaining 904 Watts "disappears".

I suppose it could be inverter consumption would go a long way in explaining the difference. At 904 Watts between the 2 Axperts we get pretty close to your 400W per inverter. However, this spread opens pretty wide in the morning, making 1800 Watts disappear into the ether. This is the time during which the inverters and batteries are heating up with the charging cycle, so I suppose that could also play a role.

I will keep a closer eye on the relationship between the temperatures on the inverters and batteries and the efficiency of the inverters at channelling that electricity into the batteries and or the load.

Thanks again for the insights. I'm just happy to hear that I am not about to burn my house down 😅

14 minutes ago, André3000 said:

Thank you HendrikBigChief

The electricity loss/leak occurs while the batteries are charging in the day. So if you look at the first picture you will see that the panels are generating 7811 Watts while the load is 5236 Watts. That should leave 2575 Watts for charging the batteries. The batteries are however only receiving 1671 Watts, which means that the remaining 904 Watts "disappears".

I suppose it could be inverter consumption would go a long way in explaining the difference. At 904 Watts between the 2 Axperts we get pretty close to your 400W per inverter. However, this spread opens pretty wide in the morning, making 1800 Watts disappear into the ether. This is the time during which the inverters and batteries are heating up with the charging cycle, so I suppose that could also play a role.

I will keep a closer eye on the relationship between the temperatures on the inverters and batteries and the efficiency of the inverters at channelling that electricity into the batteries and or the load.

Thanks again for the insights. I'm just happy to hear that I am not about to burn my house down 😅

I see in the morning there you get almost 8000W solar in, so if your inverter efficiency at that wattage is 90%, you are losing 800W right there, plus the 800W inverter usage, that is easily 1600W lost.
At that moment your loads seem to be 4200 and battery charge 2200.

So quick calculation:

8000 - 800 - 800 - 4200 - 2200 = 0 , so it checks out.

4 minutes ago, HendrikBigChief said:

I see in the morning there you get almost 8000W solar in, so if your inverter efficiency at that wattage is 90%, you are losing 800W right there, plus the 800W inverter usage, that is easily 1600W lost.
At that moment your loads seem to be 4200 and battery charge 2200.

So quick calculation:

8000 - 800 - 800 - 4200 - 2200 = 0 , so it checks out.

Yip inverter and conversion losses are a real thing.
Some inverters more noticeable than others.

Inverter power factor for battery charging and battery use is a thing yeah

That big heatsink on the back is where all the lost power is going sadly

6 minutes ago, PsyWulf said:

Inverter power factor for battery charging and battery use is a thing yeah

Ah, yes, batteries also use some power, my BMS uses around 20W, so if the poster has 5 batteries, that is another 100W gone.

Yeah I was curious about this too so built my own entity in HomeAssistant to see the inverter use and losses.

I still need to figure out what the spikes are, but essentially it calculates all the inputs less all the outputs as follows: Power from Eskom + Power from PV + Power from Battery - Power into Battery - Power into House  (I do not feed back)

At night it uses about 80W and when solar is producing max it's about 500 - 600W 

1 hour ago, Zombie said:

Yeah I was curious about this too so built my own entity in HomeAssistant to see the inverter use and losses.

I still need to figure out what the spikes are, but essentially it calculates all the inputs less all the outputs as follows: Power from Eskom + Power from PV + Power from Battery - Power into Battery - Power into House  (I do not feed back)

At night it uses about 80W and when solar is producing max it's about 500 - 600W 

What inverter are you running?

The one thing I noticed is that the numbers from some inverters are not accurate. Mine self reported around 80 to 100W, but when I used external sensors, its self consumption was more like 200. Specifically the "grid usage" number was way below actual.

Edited July 7, 20232 yr by HendrikBigChief

1 hour ago, HendrikBigChief said:

What inverter are you running?

The one thing I noticed is that the numbers from some inverters are not accurate. Mine self reported around 80 to 100W, but when I used external sensors, its self consumption was more like 200. Specifically the "grid usage" number was way below actual.

I have 2 x luxpower SNA5000 inverters

Thank you everyone

I guess that I always knew that there are losses in the system, I just did not think that the losses could be that large. I was also surprised to see that the losses are not constant, but that it varies throughout the day. Even though I am not ecstatic about the losses I am happy that it is to be expected and that there is nothing wrong with the system. 

I am moving in the near future and I'm in the process of shopping around for components for my next system. I will now add the losses on inverters as a criteria when considering the inverters I buy for that system. I'm currently looking at the 8kW Sunsynk/Deye inverters for my next installation.

May I be so cheeky to ask the audience on their opinions on the Sunsynk vs the Deye vs similarly priced inverters? 

1 hour ago, André3000 said:

Thank you everyone

I guess that I always knew that there are losses in the system, I just did not think that the losses could be that large. I was also surprised to see that the losses are not constant, but that it varies throughout the day. Even though I am not ecstatic about the losses I am happy that it is to be expected and that there is nothing wrong with the system. 

I am moving in the near future and I'm in the process of shopping around for components for my next system. I will now add the losses on inverters as a criteria when considering the inverters I buy for that system. I'm currently looking at the 8kW Sunsynk/Deye inverters for my next installation.

May I be so cheeky to ask the audience on their opinions on the Sunsynk vs the Deye vs similarly priced inverters? 

I doubt that it would be easy to find out what the "leeks" are between different makes. 

Not a big sample but have a close look at the new Solis S6 hybrid. @WannabeSolarSparky

can give you more detail. 

9 hours ago, Scorp007 said:

I doubt that it would be easy to find out what the "leeks" are between different makes. 

Not a big sample but have a close look at the new Solis S6 hybrid. @WannabeSolarSparky

can give you more detail. 

It looks suspiciously like a deye/sunsynk

1 hour ago, HendrikBigChief said:

It looks suspiciously like a deye/sunsynk

Yip when I 1st saw it I thought it was just another deye clone.
Visually it looks similar but it's Solis' own design totally different to the deye/sunsynk.

The specs on the Solis S6Pro are impressive compared to the deye/sunsynk and at a slightly better price and LOCAL SA warranty support.
And on the warranty they DO NOT REPAIR, they swop out with a new unit and send the faulty one back to China.

Some highlights of the 5kW model
SOLIS BRAND - REPUTABLE In the Industry World Wide
8kW Solar and can use many of the latest high power modules up to 16 amp and max SCC 24 amps
If you want to add solar slowly on a budget it even has a low 90v start up voltage so you can start off with 3 smaller 36v 180W panels if you like
AC output on battery - 5kW and can burst to 10kW for up to 10 seconds
This one NB - Earth/Neutral Bonding taken care of by the inverter internally

Easy configuration VIA bluetooth app with simple to understand settings pages

EVERYTHING needed to do the install and connect to the data portal is all included in the box (solar connectors wifi dongle etc and even an allen-key)
 

Price - WAY BELOW deye/sunsynk

And for what it's worth, I am not sponsored by Solis