Taking lights and internet off the Grid (mostly)

The_Ogre

Honorary Master
Joined
Apr 30, 2010
Messages
25,863
Starting from January I'm going full out. My max possible usage is on average around 700w (LED lights, solar geyser, gas stove). Fridge/freezer is rated A++, chest freezer A+++. I'm plannning to run all these during daytime using micro-inverters, unless there's insufficient sun, in which case the grid will be used as backup. During the night one (or two) of these will be used as primary power source and again, the grid will serve as backup. I need an automatic transfer switch for this.

So its:
panels/micro-inverters -> ATS -> hybrid-inverter + battery bank -> mains
grid -> same ATS as above.

The hybrid-inverter needs to be programmable to switch to the battery bank after a certain time. The ATS switching will happen automatically depending on whether there's sun or not.
 

Pineapple Smurf

Pineapple Beer Connoisseur
Joined
Aug 2, 2016
Messages
39,591
Starting from January I'm going full out. My max possible usage is on average around 700w (LED lights, solar geyser, gas stove). Fridge/freezer is rated A++, chest freezer A+++. I'm plannning to run all these during daytime using micro-inverters, unless there's insufficient sun, in which case the grid will be used as backup. During the night one (or two) of these will be used as primary power source and again, the grid will serve as backup. I need an automatic transfer switch for this.

So its:
panels/micro-inverters -> ATS -> hybrid-inverter + battery bank -> mains
grid -> same ATS as above.

The hybrid-inverter needs to be programmable to switch to the battery bank after a certain time. The ATS switching will happen automatically depending on whether there's sun or not.
Very nice setup.
Looking forward to some pics next month please :thumbsup:
 

The_Ogre

Honorary Master
Joined
Apr 30, 2010
Messages
25,863
Very nice setup.
Looking forward to some pics next month please :thumbsup:
I actually wanted to start last month already as we moved in beginning of November, but you know this kark about moving in and women always needing this and that done or bought. In the end I just gave up because that's not the kind of job you want done during December (and also because I'm broke so now I have to buy things piece by piece, instead of all at once like I planned).

The mounting of the panels, I'll obviously need someone who does it for a living to do for me. I don't want to wake up one day and find the panels lying in the neighbour's yard. :p

My only concern right now is whether its actually worth it. I know there are areas where forum members get shed at 4.5 hours a pop, but CoCT uses Steenbras to mitigate the risk. In fact, today is the first day that we've been shed since this schit started and its only 2.5 hours.

Added with the things I had the building company put in, our average consumption is currently 5kwh per day.

Anyway, I'm derailing TB"s thread now. I'll post pics as I go along :)
 

ToxicBunny

Oi! Leave me out of this...
Joined
Apr 8, 2006
Messages
99,496
I actually wanted to start last month already as we moved in beginning of November, but you know this kark about moving in and women always needing this and that done or bought. In the end I just gave up because that's not the kind of job you want done during December (and also because I'm broke so now I have to buy things piece by piece, instead of all at once like I planned).

The mounting of the panels, I'll obviously need someone who does it for a living to do for me. I don't want to wake up one day and find the panels lying in the neighbour's yard. :p

My only concern right now is whether its actually worth it. I know there are areas where forum members get shed at 4.5 hours a pop, but CoCT uses Steenbras to mitigate the risk. In fact, today is the first day that we've been shed since this schit started and its only 2.5 hours.

Added with the things I had the building company put in, our average consumption is currently 5kwh per day.

Anyway, I'm derailing TB"s thread now. I'll post pics as I go along :)

Hardly derailing it :)...

This thread is meant for all of us who are going down this road now..

As for it actually being worth it, if I was merely doing a battery backup, then no its not worth it.. but looking at adding solar panels to limit the reliance on the Eskom grid makes it worth it in the long run purely due to the rising cost of electricity and the reliability factors.
 

HunterNW

Honorary Master
Joined
Oct 21, 2014
Messages
19,597
So.... what do i look for on my appliances to calculate what size inverter i need ?
 

ProAsm

Expert Member
Joined
Aug 31, 2003
Messages
2,186
The hybrid-inverter needs to be programmable to switch to the battery bank after a certain time. The ATS switching will happen automatically depending on whether there's sun or not.
LOL... yes when I first started I too went the hole hog plus some :)
I'll refrain from posting the pics here but will give a link.

This was my original system which took a year to get to this point.

http://www.proasm.com/pics/invx1.jpg

There you can see a dedicated laptop attached to a fancy black box which was an old PC UPS.
In that box is a 20 amp charger and a very sophisticated circuit board of which I designed and built.
That pc board is connected to the laptop via a USB to RS232 interface.
You can also see a webcam attached to the solar controller, this was so I could log onto the laptop via the internet and see exactly wher my battery voltage and current drain was etc.
I also designed a very sophisticated application written in C++ which did work very well.

Here is a pic of one of the monitoring screens with the display of the webcam.

http://www.proasm.com/pics/invx2.jpg

A circuit diagram of the interface unit.

http://www.proasm.com/pics/invx3.jpg

A dump of the mains failures we had over a 9 month period generated by the app for the rate payers association.

http://www.proasm.com/pics/mns1.txt

I even started on a rotational mast that would turn my solar panels keep them pointing at the sun.
I even acquired the elevation and azimuth rotators, it was all systems go... then in July 2017 I got hit by an almighty bolt of lightning and that put paid to everything except the solar panels and batteries.

Now after getting a new solar controller and second hand inverter everything just runs to default.

Oh btw, we are currently without mains as we have a load shed from 12:00 - 14:00 :(
 

Pineapple Smurf

Pineapple Beer Connoisseur
Joined
Aug 2, 2016
Messages
39,591
I actually wanted to start last month already as we moved in beginning of November, but you know this kark about moving in and women always needing this and that done or bought. In the end I just gave up because that's not the kind of job you want done during December (and also because I'm broke so now I have to buy things piece by piece, instead of all at once like I planned).

The mounting of the panels, I'll obviously need someone who does it for a living to do for me. I don't want to wake up one day and find the panels lying in the neighbour's yard. :p

My only concern right now is whether its actually worth it. I know there are areas where forum members get shed at 4.5 hours a pop, but CoCT uses Steenbras to mitigate the risk. In fact, today is the first day that we've been shed since this schit started and its only 2.5 hours.

Added with the things I had the building company put in, our average consumption is currently 5kwh per day.

Anyway, I'm derailing TB"s thread now. I'll post pics as I go along :)
It's totally worth it, adds value to your property so win win
 

Okty

Expert Member
Joined
Aug 25, 2009
Messages
1,473
So.... what do i look for on my appliances to calculate what size inverter i need ?
Haven't done this in a while, but you should rather work out how much watt.hour you will need per day/loadshed cycle etc.

Step 1: is to look at how much watt an appliance consumes - usually on the sticker or molded in the casing of the appliance (or calculate it if they only give ampere usage).

Step 2: is to decide for how long will this appliance run per day/load shedding cycle etc, for example 2 hours, 4 hours or 24 hours? this will give you a watt.hour per application.

Step 3: Add together to get total watt.hour needed per day/load shedding cycle

Step 4: Work out how many batteries you need to supply above said watt.hour + 20% extra for unknown resistance in your network etc. This step can get more complicated depending on what battery system you use, for example, using lead acid battery, you don't want the battery to discharge below 50 - 60% DoD, so technically, you can only use 40% of the batteries watt.hour supply for instance.

Step 5: Get inverter that can supply a comfortable higher watt.hour rating or total watt that you got in step 3.

Edit: Step 4 and 5 you also have to take into account the minimum required DC voltage supplied from the batteries to the inverter. For example, if the inverter requires 48 V (DC), and you want tot use 12 V batteries, you are going to need a minimum of 4 batteries, even if you only would require 2.
 
Last edited:

Okty

Expert Member
Joined
Aug 25, 2009
Messages
1,473
Power in Watts - peak
Yes, take this into account, especially with fridges and freezers.

Problem is, most fridges or freezers don't give peak watts on startup - thumb suck is to take given watt times by 3 to get stratup watt rating.
 

Okty

Expert Member
Joined
Aug 25, 2009
Messages
1,473
yup
watts is calculated in this case as 240v x amps (or is it 220v? i always get the 2 numbers confused)

Depends, voltage we get here is 230V from Eskom. However, on the inverter manual is should state what voltage the inverter will supply, or even set to.
 

Pineapple Smurf

Pineapple Beer Connoisseur
Joined
Aug 2, 2016
Messages
39,591
Yes, take this into account, especially with fridges and freezers.

Problem is, most fridges or freezers don't give peak watts on startup - thumb suck is to take given watt times by 3 to get stratup watt rating.
my fridge consumes 120w and peaks at over 800 on startup, so i generally tell people expect 1000w on startup. Just my 2 c :thumbsup:
 

Pineapple Smurf

Pineapple Beer Connoisseur
Joined
Aug 2, 2016
Messages
39,591
Depends, voltage we get here is 230V from Eskom. However, on the inverter manual is should state what voltage the inverter will supply, or even set to.
i like that, i will just go in the middle at 230 to get a better rough value, thanx
 

Pineapple Smurf

Pineapple Beer Connoisseur
Joined
Aug 2, 2016
Messages
39,591
Ah ok, then rather use that a good safety value! :laugh:
love my kilowatt meter, over 10years old now
whats also nice is measuring fridges as these devices switch on and off all the time. It will measure the power consumed over a duration of time, like 48hrs for example. This then gives you a clearer indication as to how many watthours a device is using.
they still make kilowatt metres, this is what the new one looks like
https://www.takealot.com/digital-wa...XBXeD7ZaGroj_jRv0hkaAiG3EALw_wcB&gclsrc=aw.ds
 

Okty

Expert Member
Joined
Aug 25, 2009
Messages
1,473
love my kilowatt meter, over 10years old now
whats also nice is measuring fridges as these devices switch on and off all the time. It will measure the power consumed over a duration of time, like 48hrs for example. This then gives you a clearer indication as to how many watthours a device is using.
they still make kilowatt metres, this is what the new one looks like
https://www.takealot.com/digital-wa...XBXeD7ZaGroj_jRv0hkaAiG3EALw_wcB&gclsrc=aw.ds

Nice! yes, they are very useful!

I unfortunate didn't have one when I calculated my fridge and freezer requirements as part of my solar system, but seems my assumptions and calculations worked out at the end of the day. :)
 

Neville

Well-Known Member
Joined
Sep 13, 2006
Messages
221
Can't remember exactly (back in 2015).
R 3 000 for inverter
R 2 000 per battery
Say R 1 000 for Battery cables, wiring, and some stuff for the DB
Total = R 8 000 (but probably more now in 2018...)

What make and model is the invertor?
Can it handle solar panels?
Do you remember where you bought it from?
 

greg_SA

Expert Member
Joined
May 24, 2005
Messages
1,891
What make and model is the invertor?
Can it handle solar panels?
Do you remember where you bought it from?
It is an Axpert KS 1K. asically the most basic version. Can do solar, but very basic, just to charge battery.
I got it from SolarSolved.
 
Top