Added diversion to heating on my setup

[Dacian Todea (electrodacus)]

This was likely the worse December regarding solar at my location followed by a great November.

There was no full sunny day this month until today (there where some clouds today but still by far the best day this month and very needed with -29C outside this morning after a snow storm and just +11C inside the lowest temperature ever).

A few days ago I added the 6 extra DSSR50 and the DEXT in order to get automated diversion to heating. Last year and this one until now I just used some breakers to manually divert to heating when needed.

I also added an extra DSSR50 to automatically switch the propeller that stirs the water in the 450liter water tank during daylight (extreme overkill as that propeller motor only uses 2W).

Maybe I will need to clean a bit the wiring but everything works correctly.

From top to bottom and left to right

Row #1 the DC-DC converter 24V to 12V that supplies the mini computer and monitor then the DSSR50 that just supplies the 2W propeller during the day (turns ON when there is light on solar panels) and last there is DEXT 

Row #2 4x Phoenix circuit breakers for LED lights (for my lemon trees) for the 2W propeller for DC-DC converter and for DEXT.

4x DSSR50 for the small PV array (3kW) the outer ones for battery charging and the two inner ones diversion to heating.

4x Langir circuit breakers for the small PV array just as a simple way to disconnect the array for diagnostic.  

Row #3 & #4 some distribution blocks followed by the 4x + 4x DSSR50 for the large array half of them for battery charging and half for diverting to heating.

Row #5 Just a distribution block and a main positive breaker for the small DC loads but should add more breakers here for the 6 DSSR50 charging the battery.

 

Here is a photo I manage to take showing the mini computer above all this. That is a 14" LCD with touch so I can use cursors to check the 24h graph in detail with zoom on the right side for 8 minutes with 1 second resolution.

Here is a screenshot with the worst day production just under 1kWh for a 9kW PV array (by far the worse day since I have solar). It was a snow storm and super dark all day. Typical cloudy (overcast) day is at least 2 to 3kWh (plenty of those days this month).

 

And below the screenshot for today (best day this month still a few transparent clouds after noon and more clouds after 15:00)

Almost 30kW with 17kWh diverted to heating and almost 13kWh to battery and loads.

It was at level 3 (meaning both small and larger PV array charged the battery) until just after 10 in the morning then you see a step change in solar (yellow) when just the large array charged the battery level 2 and the small array was diverted to heating (red).

Then just before 11 it switched to level 1 meaning just the small array charged the battery and the large array was diverted to heating.

There where some clouds after noon as seen form graph but not to bad and then around 14:45 a bit more opaque clouds rolled in (just after I took the photo of the sky and the panels). 

Photo of the sky at around 14:45

And photo of the panels also at 14:45

I was surprised to see snow on the panels as I cleaned them in the morning. But there was a layer of about 2 or 3mm of very transparent ice on the panels that evaporated in part during the day but those water vapor also condensed and formed this large snow flakes covering the panels (I cleaned the panels but was late already as more clouds came in).

There was a bit of wind from est to west thus the panels on the east saw more condensation crystalized as large snow flakes. Have not noticed this thing before today.

[Dacian Todea (electrodacus)]

Full sun today and also the shortest day of the year (technically the shortest is tomorrow but no significant difference).

For my location slightly north of Regina Saskatchewan Canada the 36 x 255W (9.18kWp) PV array ground mounted with no shadows and perfectly sunny day produces  12.986kWh + 25.629kWh = 38.615kWh

This will be the lowest production in a sunny day with way more produced in January February when days gets longer and sun is higher in the sky so less atmosphere absorption.

Sunrise was just after 9 so all 36 panels where charging the battery 

until after 10 when 12 panels where diverted to heating leaving 24 panels for battery charging.

then before 11 24 panels where heating and just 12 panels where charging the battery

at around 14:30 the battery was fully charged (started at 41% SOC in the morning) and so all 36 panels where diverted to heating when heating peaked just a bit over 7kW

at around 16:00 the battery SOC was below 95% (limit set at 98%) and so battery charging was enabled and 24 panels where charging the battery for a few minutes then all 36 panels. 

At 12:55 the average solar power delivered to battery was 2464.3W and average delivered to heating was 4958.8W so total 7421W from a 9180Wpeak PV array.

The reason it was less than 9kW has to do with the time of year and my location as the sun is very low in the sky and so sunlight need to travel to much thicker atmosphere.

I will take a photo in February to see that over 9kW can be seen at noon.  

You can see the cell voltage fluctuation based on charge current and state of charge.

Below you can see the SOC (light grey) as it started from 41% in the morning got to 100% full charge around 14:30 and then discharged to 95% started charging again to 98% (the set limit) then the day was over so no more charging.

All the faded graphs after 17:35 when screenshots where made are the data from yesterday.