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A new solar installation


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We have a porch in the backyard that is covered with 18 260 Wp solar panels. They are connected to a SMA grid tied inverter and do their job quite well. Still I want to make changes to the system and slowly but surely changes are taking place. Here is why:

  • The solar is producing enough power for us the year round but that is only because we use the grid as a battery. In summer we have a lot of excess power that we draw out from the grid in wintertime. That is just how net metering works.
  • From 2023 net metering will be phased out gradually so using the grid as a battery comes to an end at a certain time.
  • The porch is a old steel construction with the panels bolted on to it and made (well they tried to make it) waterproof by using tonnes of silicone sealant. It's leaking all over the place.

So roughly the plan is to build a new wooden porch with room for the old 18 panels and an extra 18 340 Wp Trina's. New inverter and DIY a 30 kWh battery.

Here is the old porch:


Only the steel under cunstruction will remain because that's strong. Here are some pics of the build:


Next post will be the building of the new porch. To be continued...

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The panels that came from the porch are a little weird. Look at the specs:


Umpp: 49,7 V

Uoc: 60,4 V

They where connected on the SMA as 6s3p and gave a little over 300 volt during the day. The new inverter can handle 900 V and 10 A per MPP tracker but the max is 10kW. It's an Infini 5k hybrid:


It is hanging there for half a year already so I'm happy that there is some progress now.


The new Trina panels will be one string 18s MPP tracker and that will remain below 900 V even when it's freezing and below 10 A. Max power will be 340 x 18 = 6.120 kWp. The other string will be 12 panels in series so it will not come over this 900 V again. Remember, 60,4 V Uoc... Amps will remain under 10 A and max power will be: 3.120 kWp. Total 9.240 kWp. Very nice for this inverter! The 6 remaining old panels will be charging the battery by means of a PCM60X.

In the mean time the roof is getting bigger and bigger:


The steel will be cladded with wood as well for the looks. It's huge, 10,5 x 7 meters!

Next step, mounting rails and panels. To be continued...

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Good evening gents. 

I need some advice on solar panels I have 2 x 285w panels in series on my roof I'm planning to install 2 more after the lock down. Now my problem is I'm only getting around 350w from them in really sunny days. I need to know if I possibly have a problem with direction and tilt. I'm in kwazulu-natal, Richards Bay and they are facing 347°N not sure about the tilt but it's basically the angle of my roof. I have gone through all the connections and everything looks fine.

Any advice would be appreciated. Thanks 


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2 hours ago, RikH said:

The new inverter can handle 900 V and 10 A per MPP tracker but the max is 10kW. It's an Infini 5k hybrid:


Rik, that looks very nice!

But I'm confused about your inverter... are you sure it's the 5K and not the 5.5K model?  I have a 5K myself, and mine seems a lot taller than the inverter in your photo...


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  • 2 weeks later...
  • 5 weeks later...

Hi @20VT, yes everything goes well but installation isn't going that fast. The 21st I added 12 of the old 260 Wp panels and connected them to the second MPPT. The inverter is still in grid-tie modus and today was the best day with 51,5 kWh produced! Not bad is it?


About the loss of production due to mounting on a porch in stead of a roof I'm not sure I understand what you mean. Panels are on the porch's roof. But yes there is a loss of capacity because of only 5 degrees inclination. Direction is SSW which is almost ideal. Look at this irradiation diagram (is that good English?):


This diagram looks upside down for you guys down in SA I guess 😄 but for my location it is suitable and as you can see one can expect 88% of the ideal (which is S at 36 degrees). PV1 = 18*340 Wp and PV2 = 12*260 Wp so in total 9.24 kWp but you can clearly see from the screenshot above the inverter is clipping at 4,95 kW.That's the max it can handle in grid-tie mode. Now we are nearing the longest day of the year it is not that efficient but who cares. It is only Swambo and me that have to live from it.

Edited by RikH
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Thanks for detailed response.

Yes I was referring to the angle of inclination.

I needed to move my panels off the roof for an insurance claim on the roof so I mounted them on my existing porch and they are currently flat and are seeing a big loss in production compared to the roof so was interested to know what you are getting.



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  • 1 month later...

The inverter is still in grid-tie mode and doing well. Problem is it is clipping a lot. It can feed back only 5 kW but there is 9.240 Wp connected. I'm building a battery as I told already but it is not going that fast due to lack of time. Here is a sneak preview:


The upper space is reserved for the electronics in which the BMS of course plays the most important role. Cells are 206 Ah each, nominal voltage 3,22 Volt. That will give me this 16s3p configuration. So 16 x 3,22 = 51,52 Volt nominal. 51,52 x 206 = 10,6 kWh x 3 = 31,8 kWh in total.

Edited by RikH
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Furthermore we have recently purchased a 5 year old Volvo V60 Hybrid. It has a 11 or something kWh battery on board and we charge it every day from empty to full. The wallbox is now on the AC output of the inverter and is the only load on it. Today I commisioned the wallbox but it was not that sunny but it gave more than enough to charge the car direct from solar. The car will draw 3500 W max. Highest peak in solar I saw was 5.500 W while charging and the rest pushing back which means that the inverter can do more that 5 kW. Hope this will end the clipping or at least reduce it. When the car is at home during day that is... Here are some picks from the build:


The rain gutter was doing nothing and on that part of the wall should the wallbox come. So I fixed that first and came to the conclusion Swambo didn't like it. So now it became more like a makeover instead of just hanging a wallbox on that wall.


This is what it looks like now, she is happy and so am I. It works like a charm!

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  • 4 weeks later...

Today I wanted to give the build of the battery a start but this is what I found:


One cell is leaking electrolyt. Not so nice so first thing is remove it, clean the rest and replace with another cell.

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9 hours ago, Louisvdw said:

because the cells are on their side

No I don't think so. The Chinese manufacturer has responded already that they will send me a new cell under warranty. They are aware that the cells are not standing upright cause I told them. That cannot be the cause they said.

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