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pilotfish
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Amazing difference between summer and winter generation, this is my generation curve for 8 November 2017 - 40kWh at an efficiency of 6.45;

PVgen_171108.thumb.jpg.622e5fee9fbf5efbe506c2752ca91431.jpg

and this is my curve today, wringing just about every watt available - 21kWh at an efficiency of 3.39;

PVgen_180622.thumb.jpg.c78c97560960090113c3add889b88785.jpg

In mid winter I only get decent generation between 9:00 and 15:00, whereas summer generation is from 6:45 to 16:45 - peak power is a full 1kW down during winter. The problem is that I cant go below 65% SOC because there isn't enough PV power available to sync the batteries which I like to see at least 3 or 4 times a week. In summer I go down to 50% SOC and my batteries sync on most days.

At 50% SOC in summer I am basically off grid as my batteries carry me through the shorter solar night and there is more power and longer charge time available the next day, in winter I am going to grid at around 2-3am and staying there until 10am when my batteries reach 75% switching level - and then really struggle to reach sync.

I think I am going to add 12 panels (6 per inverter) on a vertical east facing surface - hopefully this will jump up my early morning production. I cant do it on the West wall because the neighbor will burst a blood vessel.

I am thinking that I will use a contactor to switch between the 12 x East panels to the 20x North panels at a suitable time to prevent the MPPT from getting confused by panels operating at varying efficiencies on the same MPPT.

Watcha all think of that plan? 

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4 hours ago, pilotfish said:

winter I only get decent generation between 9:00 and 15:00, whereas summer generation is from 6:45 to 16:45 - peak power is a full 1kW down

Same here. Winter production starts just after 9, and usually done by 4PM. Summer starts before 8AM and can run past 5PM. I have half my capacity pointing North West, which means I start a bit later in summer but get more afternoon sun. Overall, about 25% down in generation from summer.

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I can see how my system runs till +-18:50 pm in summer, and 16:50 pm in winter.

Mornings, anything from 8am or when I leave it, switches over itself by +-10am, for the SOC must first be reached, as SOC is NB for Eskom failures.

Large panels are perfect for summer, small array poised for better production in winter - accidentally.

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13 hours ago, Mark said:

Get another MPPT and add that as your vertical E string.

Probably the right way to go and I have a reserve unit already, it is just that my solar room in a small space under some stairs and a 3rd Axpert is going to make it really crowded in there:unsure:

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10 hours ago, Chris Louw said:

I find hosing the panels down every 14 days gives me a good 600 watts extra

Yes I haven't done that at all this winter, and relied on rain in summer. The panels are on top of a 6m high building so it is a bit of a witch getting up there with a hose:)

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9 hours ago, The Terrible Triplett said:

I can see how my system runs till +-18:50 pm in summer, and 16:50 pm in winter.

I think Cape Town should actually be about an hour later than Joburg if we didn't utilize a common time zone - how does your morning pickup compare?

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41 minutes ago, pilotfish said:

Probably the right way to go and I have a reserve unit already, it is just that my solar room in a small space under some stairs and a 3rd Axpert is going to make it really crowded in there:unsure:

I was thinking a small blue unit you could  slot in easily... monitoring... well...  negotiate an ICC update (was going to request it anyway) to allow for a mppt only monitoring (given thats what is done for the BMV ;)) - it then becomes another TAB in ICC...

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30 minutes ago, Mark said:

negotiate an ICC update (was going to request it anyway)

That is the sticking point - I love my data and currently a separate MPPT would blow that - an ICC update to accommodate would be great!

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4 hours ago, pilotfish said:

That is the sticking point - I love my data and currently a separate MPPT would blow that - an ICC update to accommodate would be great!

To add it to ICC, is easy, but it is still effort.

So offer ICC some remuneration for that effort, seeing you all are business minded / ROI / Value for money / like your data people?

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2 hours ago, pilotfish said:

I think VICTRON should be throwing corporate cash at Manie to interrogate Blue MPPT's - I am pretty sure that BMV sales are outstripping Multiplus sales by miles since he did that integration :)

Point to ponder yes ... BUT ...

Far as I know BMV's where being advised on here, on PF, first, before any software saw the light, here, on PF.
And the BMV's saved a lot of banks, not? So all won, V and the buyers.

Secondly, I don't see why V would want to fund anything that does not sell their main products, i.e. inverters. So why would they do that?
BMV's are a add on, extremely nice to have, not their main income, yet it did save a lot of users a trip to their banks. :P

Thirdly, why must anyone fund anything if crowdfunding exists to motivate a developer, by donating +-R50-R100 each for a feature to be added, when the manufacturer of the BMV gave the documentation for the MPPT out for free also? I mean, really!? :D

So the point to ponder makes less sense now, not?

 

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2 hours ago, pilotfish said:

BMV sales are outstripping Multiplus sales

But you need to sell 10 BMVs for each 3KVA Multi, and the BMVs sold to Axpert users is a drop in the bucket compared to what is sold to other systems (including DC-only systems in vehicles and caravans). That is more, you'd contribute more to a loss in sales on Multis by supporting a product written for the competitor than you'd make up in BMV sales. So I doubt it will ever happen...

The irony is really that it would be ridiculously simple to plug the Axpert into Venus and make it look (in software) like a Multi and a Solar Charger. The only issue at the moment is that there is no official pvoutput or emon integration, but you'd get everything else (solar chargers, BMV, PV-inverters, generator start/stop, tank level sensors, BMS integration for all the major battery makers, etc etc). But again, there is no way it's coming from this side... :-)

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8 hours ago, pilotfish said:

... - how does your morning pickup compare?

Depending on the SOC setting I have set.

In summer I can be over to solar by 9am, winter 10-11.

However, if I remember to switch the BMV relay manually (in summer, or good sunshine day), it can be from anytime I do it early morning, with fully charged bank by 12/1ish.

Have more panel capacity than loads.

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On 2018/06/23 at 1:50 AM, pilotfish said:

In mid winter I only get decent generation between 9:00 and 15:00, whereas summer generation is from 6:45 to 16:45 - peak power is a full 1kW down during winter.

What tilt are your panels? I think that at least some panels should have a pretty large tilt, say 45° (for latitude 27.5°, Brisbane Australia), so production is better in Winter and worse in Summer. That would balance to some extent the longer days in summer.

But it's far more convenient to have panels flat against roofs. Here, the roofs are often at less than 25° tilt. What's it like in various parts of SA? I imagine you don't need steep roofs to stop the snow from building up, same as in 99% of Australia.

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My winter PV production has also fallen by 40% from summer production. However I think the main reason for this is that my no.4 battery was busy going out of sync with the rest.

It was busy discharging and charging faster than the others causing the inverter to switch more rapidly. I do have an HA-02 connected.

I swapped out the no1 & no4 batteries yesterday and I can already see the difference today.

Not sure if this has been mentioned here yet, but here is an interesting article:

https://www.disclose.tv/inuit-elders-warn-nasa-and-the-world-the-earth-has-shifted-314469

 

 

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4 hours ago, Coulomb said:

I imagine you don't need steep roofs to stop the snow from building up, same as in 99% of Australia.

At 55 years of age I have never seen snow falling, I have seen a light dusting of white power on the floor but that is all. On the rare occasions that it has snowed in Gauteng I have been elsewhere - just my luck!

4 hours ago, Coulomb said:

What tilt are your panels?

My panels are on 2 sections of flat roof and have variable tilt - I can theoretically tilt them between 15' and 45' using 2 gate motors driving threaded shafts, however the system is very much DIY and requires some tweaking (the chains keep jumping off the sprockets at each end of the shafts). They are currently at about 27' and will stay there until I get the time to make the repairs required.

Luckily construction is busy collapsing along with the rest of the economy so I expect to have plenty time available soon.

PanelTilt.thumb.jpg.f2002af782e93f5342a351f4e01b1df8.jpg

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1 hour ago, GVC said:

Not sure if this has been mentioned here yet, but here is an interesting article:

https://www.disclose.tv/inuit-elders-warn-nasa-and-the-world-the-earth-has-shifted-314469

Haha, that's a beaut! 

"Nasa says global warming has caused the earth to tilt on it's axis" I have heard and read some B/S in my life but that one takes the cake:D

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34 minutes ago, pilotfish said:

the chains keep jumping off the sprockets at each end of the shafts

How about using a cheap linear actuator of sorts? The Post Apocalyptic Inventor on youtube has made some cheap DIY ones using old Mercedes Benz jacks and a wiper motor :-)

36 minutes ago, pilotfish said:

construction is busy collapsing along with the rest of the economy

That's always a bad sign. That is what happened in 2008, there was some ongoing projects that kept things going for a bit, but it was one of the knock-on reasons that eventually got me retrenched in 2010. And this in a country with a housing shortage.

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1 minute ago, plonkster said:

That's always a bad sign.

Yup - there's some tough times in the pipeline, you can read the bright signs like [Basil Read goes bust] and [PPC shares take a dive]. For me it is pretty easy to forecast because I can see the decline it cars parked outside the electrical wholesaler:(

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8 minutes ago, plonkster said:

How about using a cheap linear actuator of sorts?

Nope - the system is built and it was a hellova job that I am not about to mess with other than to make the minor repairs necessary. I have seen where and why it is failing and will be a quick fix (like a day or so).

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