If everyone’s derailing here I might as well join in. So think of this when creating the new thread .
As you mentioned you are already oversized as you can only invert ~2400W to use as AC and you have ~5kWp panels. (Just to add what I didn’t last time: I remember correctly that 2400W will be used for AC Out, but if there’s anything left it will go through AC In back to your Carlo Gavazzi meter for your AC loads and if there’s still left over it’ll be used to charged the batteries)
The main thing that I think most of us (at least me) want to do is to maximize the amount of hours in a day that you are able to make use of PV.
My suggestion would be to try and do something like this where you have all your panels in a East / West orientation:
I’m sure that should be possible on that roof and it will also look nice. You should then have more watts available to use early in the morning and late in the afternoon. Any efficiency losses from not having them facing North should not be an issue as you have ~4kWp panels and should still get your ~2400W max.
I have to agree 100%. Doing an east/west setup vs a north give you up to a hour more sunlight in the morning and also in the afternoon. With your over specced panels this would be perfect. Half will be for the morning, half for the afternoon and both will be half/half mid day.
No they can be perfectly east and west. You want to max your early morning and late evening power. So 30deg tilt up. There are less light early morning so your aim is to get it af efficient as possible.
Later in the day as the sun gets to 12:00 then it is at it’s brightest and you don’t need that great angles (cause it is not looking north) as your panels are more than what your MPPT max can use. So it will be limited anyway.
The theory is that instead of aligning north and getting your peak around 12:00, you try to get your peak around 10:00 and again 15:00.
Sorry for being slow, it being Monday and all. But still trying to understand the reason North is even being mentioned. Not just for my setup, any setup.
Is it only for winter purposes? Because of the lower angle of the sun’s trajectory then? Because I’ve seen this at my house and then it would make sense for the panels to be slightly tilted North as well?
If you are on the equator the sun would rise in the east and set in the west. You can set a PV flat on the ground and the sun will pass over the panel at a 90 deg. around noon.
When the sun hits a PV panel at a 90deg. angle the PV will produce the most power. The more that angle deviate from 90deg the less power it will produce.
Most people are far from the equator. Because we are south of the equator in SA (southern hemisphere) the sun actually pass over us always to the north. So it rises in the north-east and sets in the north west. So most panels are installed looking north in the southern hemisphere and looking south in the northern hemisphere to look towards the sun. All this is to try and get the angle at 90deg. for the longest time during the day.
In the thread I shared a few posts back, you will see an link to a PDF that Tariqe has shared. That has more detail on this and worth the read.
The north orientation generates the most power during a day, but if you orientate all your panels north, you will need more batteries to make up for the hours that the sun don’t hit the panels well.
In this case it peaks your production so that you can get as much as possible out of your solar panels around noon. In most cases batteries are already pretty much fully charged by noon and as we don’t feed into the grid we don’t really see or use that peak. A lot of people’s graphs actually shows the MPPTs stopping peak production and only produce what is being used.
So what we try and do is to maximize the amount of time that we get production from our panels by setting them up East / West instead of North. We might not necessarily peak at the same watts as having all the panels facing North, but if you have an hour extra in both the morning and the evening that you are using PV. In some cases you end up getting more production simply because of the extra ~2 hours that you are able to use PV.
I’m not 100% sure about that. I think that would only prolong your peak production time, but you’ll possibly end up shortening the time running on PV again
I have a theory that I need to confirm. I’m getting ad-hoc overload warnings.
The inverter is happily powering the house @ 2.5kw and recharging the batts @ 1.3kw, all 3.8kw coming from the panels.
Next moment Eskom goes off … sometimes I get a Overload warning.
@plonkster, my theory is that when Eskom drops off the cliff, the system having happily managing the 3.8kw from the panels, the next second dropping down to a mere 500w of Critical Loads, that that must be the cause of an ad-hoc Overload Warning. I am right?
First upgrade to Firmware 481. That might “fix it”. Not that anything is really wrong.
The Multi goes through three stages. First there is the pre-alarm (overload LED is flashing). Then there is an Alarm, and finally it switches off.
The pre-alarm happens if it cannot reach the peak 325V voltage needed to make a 230VRMS AC waveform. If it cannot manage to reach that peak (by adjusting the PWM ratio) for 30 consecutive cycles (aka around 0.6 seconds), it will switch off. If it can however reach the voltage, but it is more than 30% above max capacity, it will flash that LED for another 2 minutes and then switch off. If you are within the 100%-130% window, the LED will flash up to half an hour (or if it overheats) and then it switches off.
So it is possible that the AC voltage dipped below the peak for a few cycles and for that reason a pre-alarm was triggered. The Multi obviously recovered, so normally I’d say don’t worry about it.
But there are improvements in the latest firmware, so also update to that.
There’s been at least 300 successful updates already from early beta testers, and the development team did almost 150 updates during testing too. It’s Beta, and there’s already a fix or two coming in v2.66. If your internet line stays up during the update, it will be uneventful.
The problematic cases (where you end up having to manually reconfigure things from scratch) is where the internet itself is powered by the Multi, and where such an internet connection takes a long time to return afterwards. Then you may end up with the inverters updated, but left in default unconfigured state. It is adviseable to pull the configuration down before you start, just so you have a backup of what was on there before.
The update process does restore any configuration related to multiple units, eg three phase or parallel setups as part of the firmware update, it’s just the ve.configure part that comes afterwards.
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