My journey to renewable energy - Solar

Priapus

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So, both Pylontech batteries were fully charged by 10:30am this morning. Which is a problem.. because now I know I have room to add another one soon.. down the rabbit hole. :ROFL:

Loadshedding for 2hrs tonight. Won't even bother turning off a single light or appliance. Those batteries will not even go down to 60% in that time.
 

AchmatK

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So, both Pylontech batteries were fully charged by 10:30am this morning. Which is a problem.. because now I know I have room to add another one soon.. down the rabbit hole. :ROFL:

Loadshedding for 2hrs tonight. Won't even bother turning off a single light or appliance. Those batteries will not even go down to 60% in that time.
My system is set to prioritise loads then batteries.

Load shedding just started. My batteries were at 12% from 2am and it still managed to charge the batteries to 79% by 12:00. No risk to potential solar wastage if the batteries were at 100%.

Trying my best to balance the system so it doesn't need to throttle pv output. Screenshot_20200904-121752_SOLARMAN%20Smart.jpg
 

AchmatK

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So much for that plan. Pv added 20% to the the battery in the last hour.

Battery bms is limiting charge and inverter is throttling pv output.

Potential pv lost wil probably be 3kwh. Screenshot_20200904-131033_SOLARMAN%20Smart.jpg
 

Priapus

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Yeah at the moment I have a lot of waste that will only be solved by adding more batteries. I am planning to go to 4 - maybe 5. Which would see me through the night. I have a ton of waste, PV output is now like 1kw/h - out of a potential 3-4kwh till 16:00
 

AchmatK

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Yeah at the moment I have a lot of waste that will only be solved by adding more batteries. I am planning to go to 4 - maybe 5. Which would see me through the night. I have a ton of waste, PV output is now like 1kw/h - out of a potential 3-4kwh till 16:00

And down the rabbit hole we go.

I don't like wasting anything.

Also plan on having 5. Hopefully by the end of next month.

Do you know if pylontech makes longer battery interconnect cables? Just need it to be double the current length as my batteries are in a full cabinet and want to mount the new batteries on to of the cabinet. Else I will need to sell the cabinet and get a bigger one to accommodate up to 8 batteries.
 
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Priapus

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Do you know if pylontech makes longer battery interconnect cables? Just need it to be double the current length as my batteries are in a full cabinet and want to mount the new batteries on to of the cabinet. Else I will need to sell the cabinet and get a bigger one to accommodate up to 8 batteries.

Not that I know of, sadly. I too will have that issue with I get to the 5th battery. :confused:
 

cfvh600

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Not that I know of, sadly. I too will have that issue with I get to the 5th battery. :confused:
You could split them up into 2 stacks, each stack connecting to a busbar box, and from there it connects to the inverter.
 

AchmatK

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You could split them up into 2 stacks, each stack connecting to a busbar box, and from there it connects to the inverter.
And the very short battery com cable linking them? Is it a standard cable?
 

Priapus

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So, taking what @Sinbad does with his Pool + Battery SoC
I decided to do this in Node-Red - comes down to this: "If battery SoC is below 98% AND PV is below 1600w = pump off. Else Pump on"

This should turn the pump off when there is cloud cover and then back on again, if PV was enough to charge th battery. Meeting the 98% SoC + PV > 1600w

Might need fine tuning. But will test it out for the day

Screenshot 2020-09-05 at 10.15.04.png
 

Speedster

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So, taking what @Sinbad does with his Pool + Battery SoC
I decided to do this in Node-Red - comes down to this: "If battery SoC is below 98% AND PV is below 1600w = pump off. Else Pump on"

This should turn the pump off when there is cloud cover and then back on again, if PV was enough to charge th battery. Meeting the 98% SoC + PV > 1600w

Might need fine tuning. But will test it out for the day

View attachment 906106
I'm assuming you have the pool on a sonoff or something similar?
 

hxc87x

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Hi all,

At the start of this year, I made the decision that it's time to get off the grid as much as possible and reduce my reliance on old un-faithful, Eskom.

I wanted a system that I could scale up and add PV panels as and when I needed. With the help of a good friend, we set out doing the research and designing of the system. Of course, no system could be designed, without finding out what the house consumed and what the requirements where.

Back in June, we installed some power monitoring into the DB of the house, that feed the data into my Home Assistant Setup and Grafana so I could have some historical data too, besides just realtime data.

I was then able to setup Home Assistant to show the houses current and daily usage - like so:
View attachment 888782

It's not pretty (for now) but it is functional and gives me an idea of what loads the house experiences (average and peak)

As mentioned - in Grafana we are then able to get historical data to get peak loads and average loads: This is over a two day period.

View attachment 888784

With that, we had the requirements in terms consumption and usage patterns.

The goal for the system was to meet the following requirements:

- Power the whole house, this includes every plug and every light. I don't want to have certain plugs only working when the grid is down.
- Run on PV generation through the day as much as possible
- Battery backup to last 8hrs or more with the whole house powered

To meet these goals, we will keep the stove, oven and geyser (for now) on the grid. The stove will be converted to gas later on in the year. With the heavy loads off (Except the A/C in the lounge, which will be powered by the PV / batteries) - we then had the last bit of the requirements down, and was ready to size and spec the system accordingly.

The hardware

Decided on the following hardware

Inverter:
- Kodak MKSII 5Kva off-grid inverter.


I know this model does not do blending and when the PV generation can't cope with the load, the inverter will switch to the grid. Which I am okay with, as this will only happen a few times a day, if that and in a load-shedding situation, we won't be using heavy loads at all anyway. I would have liked to have gotten the "Blue stuff" - Victron MultiPluss unit, but there wasn't 30K in the budget just for the inverter.

Panels:
12 x 410W CanadianSolar panels.


If my maths is correct, these panels should generate around 3.2Kw at peak - which is roughly 65% efficiency.
I'll be mounting them on the roof - facing just slightly off north by a few degrees. The plan is to connect them in 3 strings of 4.

Energy storage:

With that much generation, I need somewhere to store the energy for use later. One of the requirements is also to run the house without the heavy loads (Above 2Kw/h) for most of the night.

Battery: Pylontech US3000 - 75A / 48V / 3600wh. Now just one of these won't do. I'll get around 3.5h out of it at current load (800-900w constant) - the plan is to upgrade the bank to 3 of these batteries. Second battery to come at the end of the month.

Software Monitoring:

The inverter isn't fancy enough to have cool built in monitoring. However the guys over at ICC Software supply a nice kit which I can monitor the whole system remotely and tie it into my Home Assistant / Grafana setup. I'll then make a pretty dashboard for it finally too.

I took delivery of the above this week on Wednesday and to say I am excited is an understatement . I cannot wait to have the system installed next weekend!

View attachment 888800
View attachment 888806 View attachment 888808 View attachment 888810

I'll be following up in this thread with the install and of course more photos and details.

Thanks for reading!

Awesome thread!

2 questions:
1) what did you use to measure this: 1599310643687.png

2) Did you end up leaving the geyser on the grid or did you put it on the PV/backup?
 

Priapus

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Awesome thread!

2 questions:
1) what did you use to measure this: View attachment 906296

2) Did you end up leaving the geyser on the grid or did you put it on the PV/backup?

Thanks.

1. I have Sonoff POW R2 attached to pool pump, geyser and in the server cabinet. (Though that’s not there anymore) - the devices are flashed with ESPHome and connected to Home Assistant.

2. Geyser is still connected to the grid. I have considered putting a 2kw element in there and running it off the solar. However I think whatever I do will cost more than just leaving it tied to the grid. So might do just that... haven’t decided as yet.
 

Priapus

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Both my 2kw geysers are running off solar. This reduces the Eskom use by a large amount and no PV goes to waste.

What size geyser do you have and how long do they take to heat from hold? I need to test to see if I heat my geyser later in the day, that it will then still be hot in the morning.
 

cfvh600

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What size geyser do you have and how long do they take to heat from hold? I need to test to see if I heat my geyser later in the day, that it will then still be hot in the morning.
The geysers are 150l each. I only heat them during the day. On the 1 geyser the kids can have a bath in the evening and then the water is still hot enough in the morning for a shower.
 

Priapus

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Small update.

It's been a full month since the system has been running 100%.

CoJ bill:

Previous: (before installation started)
Usage: 936 kWh total
Daily: 36 kWh average
Amount R2500

Latest:
Usage: 610 kWh total
Daily: 19 kWh average
Amount R1700

I am optimising the system a bit more and hoping to save more on the bill.

I'd say that's a decent start to savings.
 
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