Rouxenator
Dank meme lord
Nope, I am only using 1 MPPT at the moment and it works fine. You can configure them though :
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Question of the Day: Have you ever ordered a product online and received a fake knock-off?
3KW or 5KW setup - please advise
- Thread starter Rouxenator
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lexity
Honorary Master
Are those 3x 545w panels the 2.2 x 1.1m, 30kg variety?
wingnut771
Honorary Master
All 545W panels are the same.
eepr0m
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2x hubbles are fine given they are rated 1c . 4mppts means you can have 4 strings instead of 2. More mppts could be beneficial instead of being limited to two like I am on my one install where we use a 8kw deye.
Rouxenator
Dank meme lord
Indeed - there are 4 in total, one hidden below the chimney and it's this guy that is keeping my setup from going full power until about 11am since the house to the left casting a shadow on it. Unfortunately, there was nowhere else to position it.
wingnut771
Honorary Master
This is why I told you to can the solar geyser POS.
Rouxenator
Dank meme lord
It works like a dream - with the sunny days we had this week it went from 17°C in the morning to around 65°C by sunset. Not bad for 200L water in winter.
In fact, right now if the battery is around 35% at 9am and I run the dishwasher, washing machine and the coffee machine a few times I still end up with a full battery by just after 2pm. Thinking of getting a bigger battery and taking this one to our seaside house.
lexity
Honorary Master
Hm. Don't know what the load/draw is but those look like pretty solid shadows.
Still more than 10am, mind you.
wingnut771
Honorary Master
Okay, but at what time is your battery at 100%? Looking at that graph, it's around 11am.
Be honest. How many days in winter is it at 65c?
Rouxenator
Dank meme lord
That dip at 11am I am not sure of - but the one around 14:30 was when the battery was 100%. Getting to summer I think going with a larger battery will mean I can run without eskom for longer, maybe even completely (except for the stove and pool pump).
As for the geyser, only with the very sunny days we had this week does it reach 65c. On a day like today I think it was around 35c when I woke up and 57c by sunset, so only a 22c rise. Still if you do the maths for the very sunny days we had : 19c to 64c is 45c, it takes 4kJ to heat 1L by 1c so for 200L it is 4 x 45 x 200 = 36 000kJ so if 1kJ = 0.000278kWh then that is 10kWh. Not bad at all. Even on a day like today when it did half that it's still 5kWh.
For comparison I was only able to use 9.3 kWh at best from the PV panels this week, may have gotten 10 if I had storage for it.
wingnut771
Honorary Master
I can guarantee you if you replace your solar geyser roof real-estate with 2 more panels , then you will have 65c water everyday during winter.
lexity
Honorary Master
Are you saying just the two panels alone would be sufficient to achieve that effect? Or that when installed specifically as a supplement to the existing panels it would achieve that effect?
lexity
Honorary Master
That's an average PV generation of 8.3kw per day. From 4 panels, a 5kw battery, 5kw inverter. Is right? And one panel is shaded part of the time.
Not bad. But I guess one has to factor in the cloudy days. Beginning of Aug has been quite sunny.
Questions:
1) Are you in danger of hitting the max inverter capacity when it comes to draw/load? Do you know what your maximum load is at any given point in time? Would that be the 3kw+ at around 17:00?
2) Do you lose the entire panel's capacity when a portion of it is shaded?
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RonSwanson
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Nothing crazy about it, it looks beautiful.
It looks like the home of a man who, instead of whining, has actually gotten off his butt and done something about the sorry state of electricity affairs in this country.
Well done, may the sun bless your panels with billions of photons every day!
Rouxenator
Dank meme lord
I think you could be right actually - two more panels will... maybe a DC element added to the old geyser....
The first solar geyser burst around the start of May after 10 years of service. The old 150L Franke is still up there but disconnected. If I knew then what my PV plans would be a month later, I would have gotten the Franke wired up again and ditched the solar geyser.
So, I get your point. Sadly, I already invested a lot in that solar geyser this year so I'll see what I can reap from it.
1) The max from the panels should be 2.18kW, maybe I will reach that in summer when the sun is at a more optimal angle. Being MPPT I am pretty sure the inverter will draw as much load as it needs. Voltage is the big concern with MPPT and panels in series and I am very much on the lower to mid range of what this Luxpower can handle with my 4 panels :
2) For a single panel, or those connected in series, shade does negatively affect it. Yet here is an interesting thing I observed so far. When it is a dry night and there is no dew on the panels, the 4th one that has shade on it till 11am keeps the power down until it has full sunligh, as is the case with the graph below:
Just before 11am and it's still only doing 1amp from the panel array.
Today however there is dew on the panel, and I get a much smoother increase in power from as early on as 9am, which leads me to believe the dew is helping some what?
Hitting 1kW much earlier than on a day with no dew.
Thanks, to be honest it was your last post about going 5kW instead of 3kW even if it means squeezing in that 4th panel into creative spots. Which is when I looked into that nook below the chimney. Very glad I did.
lexity
Honorary Master
Even the shaded portion would still be receiving diffused light. So I'd be very surprised if nothing at all was generated... although shade could bring you to below the mppt requirement. In which case it's as good as midnight out there.
The voltage range if I recall is 100 - 370v.
So, that's 42v x4 = 168v, at full capacity?
In terms of losses, when does one deduct the 70% efficiency from panels? Is it after the advertised panel wattage(550w), or before?
Rouxenator
Dank meme lord
Good question about the losses, in my case the theoretical max would be 2.18kW yet the most I have seen 1.9kW - considering this is winter sun not hitting the panels at a 90 degree square angle. Still if you take 70% of 2.18kW that gives you 1.53kW and I am getting well above that. Not sure if it is because these are mono panels or if the 70% is factored in up front in the marketed power output.
wingnut771
Honorary Master
You already have panels. You’ve just added more in the space where the geyser was giving you even more production.
wingnut771
Honorary Master
I wouldn’t bother with dc element. Just use your extra panels connected to your inverter to power it normally with ac.
Maybe get a smaller 2kW element so it doesn’t put too much load on inverter.
Rouxenator
Dank meme lord
Not sure if things are different in elsewhere, like the City Of Cape town, but I had no issues adding my installation to the house insurance without the municipality knowing. All I had to do was email the insurer the certificate of compliance and the quote I accepted.