SauRoN's SomeWatt Solar Install

RonSwanson said:
Excellent results, you have summarized it pretty well.

On the panels, placing East/West and North on the same MPPT will not have the greatest outcome. You may want to consider a baby (2- 3.6K max) Solis on the Aux to provide another 2 MPPTs. It's cheap, and you can have East and West on the Sunsynk, and one of the Solis MPPTs facing North. And another MPPT spare to play around with :giggle:
I have considered this with my 5K Sunsynk, and would probably have done it already if I weren't seriously considering relocation.
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Why? It was your explanation of each string being independent that finally made it make sense to me and not each MPPT.
 
Chatted to Dyness and while I quoted the wrong model number (BX4100 instead of A4100) I’m sure they are essentially identical.

There is an undocumented 15% hard shutdown built into the BMS which is a little bit bullshit because you should be allowed to do what you want, but at least this means you’ll never have a warranty fight.

Funnily enough it was 14% when I experienced it the first couple of times but is not 15% so I guess it calibrates over some time.

Not the end of the world, I always had planned or fix it at 20% day to day but with Load Shedding it’s a bit annoying.

To their credit the tech support at Dyness was quick and thorough and had absolutely no issues chatting to an end user/consumer.
 
SauRoNZA said:
Why? It was your explanation of each string being independent that finally made it make sense to me and not each MPPT.
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I don't think each string is independant. IIRC the strings are bonded together at the inverter.
 
Speedster said:
I don't think each string is independant. IIRC the strings are bonded together at the inverter.
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Good point, these are the confusions of my life.

I wonder if having East and West on one MPPT wouldn’t be a weird hack considering only one would be “online” at a time.

But even so how much of an efficiency loss are we really talking about here? Is it a 1% or a 5% or a 50% equation @RonSwanson?

And for absolute clarity while we discuss it, the voltage limits are per string, not per MPPT right ?
 
SauRoNZA said:
Good point, these are the confusions of my life.

I wonder if having East and West on one MPPT wouldn’t be a weird hack considering only one would be “online” at a time.

But even so how much of an efficiency loss are we really talking about here? Is it a 1% or a 5% or a 50% equation @RonSwanson?

And for absolute clarity while we discuss it, the voltage limits are per string, not per MPPT right ?
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You could perhaps go east/west of you put optimisers on the strings. You'll lose quite significant production otherwise as strings revert to the lowest performing panel.
 
Speedster said:
You could perhaps go east/west of you put optimisers on the strings. You'll lose quite significant production otherwise as strings revert to the lowest performing panel.
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2P strings on east/west (one string east, one string west) on one MPPT1, one string north on MPPT2.
 
Elev8r said:
@SauRoNZA keen to get another opinion on the fan noise of the 8KW Sunsynk, how are you finding it? I may have the 8KW Deye installed in my entranceway close to the lounge, in a (ventilated) cupboard/enclosure, but a bit worried about fan noise.
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Mine is also in the garage. When my workers open the door to the garage that's just down the hall from my home office door i can hear that sweet sound of those 3 fans cooling down my free energy machine quite loud. I would not mount inside the house if at all possible.

My fathers install is also in the garage and about 25m maybe away from the db.
 
SauRoNZA said:
Why? It was your explanation of each string being independent that finally made it make sense to me and not each MPPT.
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When it comes to shading of one panel in a string, yes, it will affect that string only. If you orient one string azimuth East, and another West, and then use the same MPPT, the lower voltage on either string (before and after 12H00) will pull the overall MPPT down. It's most efficient to dedicate an MPPT for panels with the same azimuth and tilt.
 
SauRoNZA said:
Good point, these are the confusions of my life.

I wonder if having East and West on one MPPT wouldn’t be a weird hack considering only one would be “online” at a time.

But even so how much of an efficiency loss are we really talking about here? Is it a 1% or a 5% or a 50% equation @RonSwanson?

And for absolute clarity while we discuss it, the voltage limits are per string, not per MPPT right ?
Click to expand...
Per MPPT.
 
RonSwanson said:
When it comes to shading of one panel in a string, yes, it will affect that string only. If you orient one string azimuth East, and another West, and then use the same MPPT, the lower voltage on either string (before and after 12H00) will pull the overall MPPT down. It's most efficient to dedicate an MPPT for panels with the same azimuth and tilt.
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Does the voltage not stay constant?
 
RonSwanson said:
When it comes to shading of one panel in a string, yes, it will affect that string only. If you orient one string azimuth East, and another West, and then use the same MPPT, the lower voltage on either string (before and after 12H00) will pull the overall MPPT down. It's most efficient to dedicate an MPPT for panels with the same azimuth and tilt.
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Sure but are we talking 10% efficiency here or like 90%?
 
SauRoNZA said:
How does that change things? Runs them both as one but would effectively only be one at a time due to East and West being so far removed?
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We run roughly East and roughly West PV strings with 5 Canadian Solar 360w panels in each string through a Victron 250/70 MPPT. Early morning and late afternoon there is only one string active but the closer we are to midday the more both strings are active, I have seen PV power peak at more than the combined kW rating of each string in the middle of summer. This setup does suffer in winter though, the angle of the sun plays a huge part and we have issues with shading early morning and late afternoon.
 
Neuk_ said:
We run roughly East and roughly West PV strings with 5 Canadian Solar 360w panels in each string through a Victron 250/70 MPPT. Early morning and late afternoon there is only one string active but the closer we are to midday the more both strings are active, I have seen PV power peak at more than the combined kW rating of each string in the middle of summer. This setup does suffer in winter though, the angle of the sun plays a huge part and we have issues with shading early morning and late afternoon.
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Yeah for me the East and West would be purely supplementary to the North strings.

So the question would really be if the efficiency loss is worth the complexity and cost of an external MPPT.

And if I do go that route I might as well leave everything north facing “as is” and then just buy 10 more panels and put 5 on the East and 5 on the West.
 
SauRoNZA said:
Yeah for me the East and West would be purely supplementary to the North strings.

So the question would really be if the efficiency loss is worth the complexity and cost of an external MPPT.

And if I do go that route I might as well leave everything north facing “as is” and then just buy 10 more panels and put 5 on the East and 5 on the West.
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I am keen to see what the efficiency loss is with an East/West setup, we unfortunately had little choice due to very limited North facing roof as well as shading from large tree's on the North side of our property. Our new house I will look at as much North facing PV as I can possibly squeeze in before looking at East/West.
 
Elev8r said:
@SauRoNZA keen to get another opinion on the fan noise of the 8KW Sunsynk, how are you finding it? I may have the 8KW Deye installed in my entranceway close to the lounge, in a (ventilated) cupboard/enclosure, but a bit worried about fan noise.
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I also have the 8kw Sunsynk, the fans are too noisy for installation inside a house unless it is enclosed (you will need decent cooling plus it will have to be designed to keep the dust on the outside of the enclosure as these tend to suck dust inside)

Mine is in the garage and with the door closed it is not audible inside the house even when standing close the door.

We had a number of days this past summer where the fans would turn on at 6am and off again only around 10pm, granted Cape Town had a few days in the very high 30's or low 40's.
 
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