Solar power system installation - a first-hand account

Greglsh said:
I would go with a 2kw element, that is what I did, a 1kw will use the same amount of power just takes 3 times longer to heat the water. What I did was look on a sunny day when we have excess power and then set the geyser to run for 45 min in the morning excess and 30 min in the afternoon excess. Also with regards to the geyser, my 2c worth rather install more panels than go solar geyser. Once your geyser is hot then that is it, with solar panels you can use that extra power once the geyser has been heated with the system.
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With the array size i would do 1
(If single bath session at night)

So lets say he 2kw element gets 3kwp
Geyser uses 2kw that leaves 1kw


If battery reserve is in play
So any use that exceeds 1kw like making coffee will come from eskom even if full sun

Luckily the battery will be full most of the time , so maybe doing smaller element isn't needed, but the battery would have to micro cycle to get the most out of it

Now lets say semi cloudy and production dips to 1kw
Now you are using eskom to heat geyser if the battery is worked down to reserve

So you would have to change the reserve % based on weather /shedding

Small battery bank means lots of micromanaging inverter to get most savings
 
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Greglsh said:
I would go with a 2kw element, that is what I did, a 1kw will use the same amount of power just takes 3 times longer to heat the water. What I did was look on a sunny day when we have excess power and then set the geyser to run for 45 min in the morning excess and 30 min in the afternoon excess. Also with regards to the geyser, my 2c worth rather install more panels than go solar geyser. Once your geyser is hot then that is it, with solar panels you can use that extra power once the geyser has been heated with the system.
Click to expand...
But at the moment more batteries is needed first (usage based naturally but very likely)

if battery is full early or most of the time he isn't using all the solar he can produce

Doing a dump load day will give an idea
 
We have a similar system to the one described. Only problem is RF interference from the inverter which will affect a minority of people. We have two batteries and it serves us well. Eskom bill was R1k last month and R1.3k this month. We have a pool, filter motor runs 6 hours daily.
I agree with regards to the geyser element. Ours is 3Kw, 2Kw would be fine. I have a Wi-Fi switch for the geyser. The cost was a bit more than the example but it was worth it.
 
leon.davibe said:
With the array size i would do 1
(If single bath session at night)

So lets say he 2kw element gets 3kwp
Geyser uses 2kw that leaves 1kw


If battery reserve is in play
So any use that exceeds 1kw like making coffee will come from eskom even if full sun

Luckily the battery will be full most of the time , so maybe doing smaller element isn't needed, but the battery would have to micro cycle to get the most out of it

Now lets say semi cloudy and production dips to 1kw
Now you are using eskom to heat geyser if the battery is worked down to reserve

So you would have to change the reserve % based on weather /shedding

Small battery bank means lots of micromanaging inverter to get most savings
Click to expand...
On a sunny day anyway to charge batteries in the day, once full run your house directly from panels and then run off batteries at night till morning and then back to charging in the morning and repeat. I assume in this scenario 2 x 5kw batteries would be ideal?
 
Thanks everyone, will take your advice to heart (and mind) and consider our options.

Ideally, yes, we would want to upgrade with an additional battery in the near future. Just want to see what value we can get out of this system without blasting through its battery life.
 
Install looks great! Welcome to the green side.

Is that install electrically compliant? I’ve been told that AC and DC cable cannot sit in the same trunking. Also I don’t see a relay activated Earth/Neutral bridge. Just something to double check.
 
duderoo said:
On a sunny day anyway to charge batteries in the day, once full run your house directly from panels and then run off batteries at night till morning and then back to charging in the morning and repeat. I assume in this scenario 2 x 5kw batteries would be ideal?
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Yea that is the dream

Even if it doesn't fit perfect
you discharge as much as you are willing and then charge/run load of solar


In my case i have 7kwh battery
3.65kwp and find that there are times when the battery is full &
All the load is carried thus panels are throttled

So my panels produce the 2kw load i have

switch on the kettle and it bumps up to whatever the panels can do at the time

Meaning i have wasted capacity
So if i can enlarge the battery it would mean more savings

Weigh up additional savings vs cost of battery

If however i was pulling overnight on said capacity then there would be little reason to add more battery except for bad weather resistance/savings by rolling over usage to recharge the next day
 
Now look into pairing that nice setup with Solar Assistant:

Real-time solar monitoring from a Raspberry Pi | SolarAssistant Software

Real-time charts, analytics and power management from via a Raspberry pi - the most powerful, cost effective device on the planet.
solar-assistant.io solar-assistant.io

Then look at integrating it with a little home assistant Pi or VM machine running somewhere. It's real easy,.
Some basic smart lights, smart power plugs and some tinkering with the routines so you know visually when the power goes out or you can auto switch off high usage devices later at night if Eskom k@kked out and battery is getting low etc.

You'll have a hands-off system and your life will improve 10 fold... no need to oversize and spend tons of cash if you plan and work smart.

You can thank me later.
 
RaptorSA said:
Now look into pairing that nice setup with Solar Assistant:

Real-time solar monitoring from a Raspberry Pi | SolarAssistant Software

Real-time charts, analytics and power management from via a Raspberry pi - the most powerful, cost effective device on the planet.
solar-assistant.io solar-assistant.io

Then look at integrating it with a little home assistant Pi or VM machine running somewhere. It's real easy,.
Some basic smart lights, smart power plugs and some tinkering with the routines so you know visually when the power goes out or you can auto switch off high usage devices later at night if Eskom k@kked out and battery is getting low etc.

You'll have a hands-off system and your life will improve 10 fold... no need to oversize and spend tons of cash if you plan and work smart.

You can thank me later.
Click to expand...
Agree, I got this from Geewiz and it works pretty well
www.geewiz.co.za

Solar-Assistant Pre-Loaded Raspberry Pi Package (No Monthly Fees) - *Excludes Battery and Inverter Cable*

Raspberry Pi device fully assembled and preloaded with SolarAssistant. Perpetual license, no monthly fees. Inverter USB and Battery RS484/RS232 cable not included.
www.geewiz.co.za www.geewiz.co.za
 
leon.davibe said:
Yea that is the dream

Even if it doesn't fit perfect
you discharge as much as you are willing and then charge/run load of solar


In my case i have 7kwh battery
3.65kwp and find that there are times when the battery is full &
All the load is carried thus panels are throttled

So my panels produce the 2kw load i have

switch on the kettle and it bumps up to whatever the panels can do at the time

Meaning i have wasted capacity
So if i can enlarge the battery it would mean more savings

Weigh up additional savings vs cost of battery

If however i was pulling overnight on said capacity then there would be little reason to add more battery except for bad weather resistance/savings by rolling over usage to recharge the next day
Click to expand...
How long would it take to recharge a 5kw battery via 6 panels on an average day?
 
duderoo said:
How long would it take to recharge a 5kw battery via 6 panels on an average day?
Click to expand...
Well that isn't an easy question to answer.
Firstly what is the load like, how far did you discharge the battery, how big are the panels, are they north,east,west,south facing and by average do you mean no clouds, some clouds or from which area?
 
Lupus said:
Well that isn't an easy question to answer.
Firstly what is the load like, how far did you discharge the battery, how big are the panels, are they north,east,west,south facing and by average do you mean no clouds, some clouds or from which area?
Click to expand...
No load and sunny day.....assuming 550w (prob wont get that) x 6 = 3kw so maybe 2 hours?
 
For example I've got 4.3kw of panels installed, I've got 10kw of battery installed
1711440881199.png
But with my load being 1385 and the sun only providing 1530, the battery is barely getting anything. It is a cloudy day as you can see by the solar PV icon :-). But we are getting times where it's jumping to 3.5 sometimes 4. So will hold off.
 
Lupus said:
For example I've got 4.3kw of panels installed, I've got 10kw of battery installed
View attachment 1681515
But with my load being 1385 and the sun only providing 1530, the battery is barely getting anything. It is a cloudy day as you can see by the solar PV icon :). But we are getting times where it's jumping to 3.5 sometimes 4. So will hold off.
Click to expand...
So you running purely for free in a way I guess looking at the above?
 
Lupus said:
Honestly, with that size install, I wouldn't bother with the geyser, you'd have to manage it extremely carefully so that it doesn't run when there isn't sufficient sunlight and even at 1.1kw depending on the amount of water required to heat could take ages.
Either go gas if you want to be removed from Eskom, or for extreme backup scenario get a generator of 7.5kva min installed with a switch over as backup for days you need the geyser running if you have extended downtime.
Click to expand...

We run an almost identical system and have the geyser running off the solar panels in the afternoons. It's not that hard to track usage and make adjustments. Even during winter. We recently had the element changed so it draws less power.
 
duderoo said:
How long would it take to recharge a 5kw battery via 6 panels on an average day?
Click to expand...
Depends

But if you get somewhat decent production

With just one 5kwh battery most days it is preventing it from charging full to soon that is the problem

ie don't care if sun doesn't get it full , then i just use eskom

Cause i would rather power load from sun vs charging and pick up the slack of charging from eskom thus i know i use whatever solar is available
 
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duderoo said:
So you running purely for free in a way I guess looking at the above?
Click to expand...
Sure, but no battery top up at all at that point, you want the battery being charged while also running for free :)
Like now it's at least putting a bit back into the battery
1711444928884.png
 
zolly said:
We run an almost identical system and have the geyser running off the solar panels in the afternoons. It's not that hard to track usage and make adjustments. Even during winter. We recently had the element changed so it draws less power.
Click to expand...
You just need a week of clouds and you'll see it's not that easy to track, especially if you're not home or someone turns on a heavy appliance. Look it might be cause I've become more paranoid after December, but yeah I try to make sure I've got backup of my backup.
Plus you don't know his load before the geyser, if he is sitting at 1kw already, adding another kw in the afternoon could start chomping battery, even if it's small amounts.
 
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