Good morning everyone. 

I would like to start my off grid journey this year, finally being out of debt (except home loan). I don't have the capital to do everything once off, so hoping to be able to do it piece by piece. 

I have a couple of questions and hoping the community would be able to assist. From some research, it seems the most popular set-up is this: 

• 5/8kW Sunsynk Hybrid Inverter
• JA 540W Solar panels
• Some form of lithium batteries

I was considering converting my geyser to solar first, but then people with existing systems mentioned that although it's less efficient to power a geyser, from PV panels, it is more value for money to get extra PV than say having a dedicated solar geyser kit. E.g. 15-20k extra solar panels vs a dedicated geyser system. 

• What are the thoughts around the above for people that already have off grid/grid tied systems in place?
• Assuming I go piece by piece, starting with the inverter, would it be possible for the Sunsynk to be installed with one set of batteries and then later more added? I know it's not great to mix old and new batteries, so would this be possible? I know some inverters allows you to install multiple "packs", but I can't seem to find information on the Sunsynk/don't know what to Google for. 

I average about 15-20 units per day, so I'm going to get myself one of those Efergy monitors, to determine when most power is drawn, but I assume it will be when the geyser is running. 

• How do I calculate the battery and solar panel size needed? (Taking battery DOD, rainy days and so into account). 
• Note: There is no female in my household (yet, but I should cater for this anyway) so no hair dryers and things like that 🤣

Looking forward to some advice 🙂

Edited January 26, 20223 yr by FriendlyToast
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3 hours ago, FriendlyToast said:

I was considering converting my geyser to solar first, but then people with existing systems mentioned that although it's less efficient to power a geyser, from PV panels, it is more value for money to get extra PV than say having a dedicated solar geyser kit. E.g. 15-20k extra solar panels vs a dedicated geyser system. 

This is a huge debate on this forum and everyone will have their own view on the matter. For me, it makes more sense to have enough PV to power everything including the geyser. Yes an EV tube geyser is more efficient, but spending that much on a geyser that can only heat water is a waste of funds, whereas using that R30k odd to add more panels is money better spent. My reasoning is that the additional power produced can be used for anything you choose. 
Like I said, everyone is entitled to their own opinion, so feel free to disagree, feel free to give me charts on how much better a solar geyser can perform on a cloudy day. It’s all a matter of what works best for you. 
 

Personally I go for more panels to produce more power that I can use wherever I need it. 😊

Someone else can comment on the inverter/battery question….

Hi Friendly,

 

I went exactly the same route as you are mentioning. I splashed a bit and rather got the 8kw Deye inverter, but could only afford 12 380W panels and one 5.1kw battery. We swopped my Geyser's element with a 3kw element and at this stage when the sun is shining properly the battery and PV carries the geyser. I only run my geyser element from 10:00 to 15:00 but most days the Geyser is at 65 degrees by 12:00 this is when my pool pump comes on and run until 15:00. We also swapped our Gas/Electric oven for a full gass one.

My savings so far is around R1500 a month.

Hopefully I can buy another 8 to 10 panels and another battery before winter to run the geyser a bit longer.

 

Edited January 26, 20223 yr by JacoG

I think powering a geyser with PV is going to be the best bang for buck. My biggest concerns are around batteries. I don't know if I'd be able to add more batteries later and how this would affect existing batteries. Thanks for the feedback so far! 🙂

Edited January 26, 20223 yr by FriendlyToast
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Yes I must say, in winter this setup will draw the battery's flat at night if you want to run the geyser later. My battery only lasts until 2:00 in the morning currently with the one battery. My father started with two batteries on his farm and later added another one, not sure how this impacts the older battery.

You can add more batteries after the fact - especially if its within a short period. Hubble, Shoto, FreedomWon, Dyness, Alpha all allow that on the Sunsynk. I currently have a 5kw SS and it works great at blending the PV, Grid and Battery. I have a small PV array (2.4kwp) and will be increasing this in Feb to at least 5kwp. I also have 1 4.8kwh battery and the hope is to increase this by 1 more to take us through the night. Most of my usage is mid morning with another peak in the evening (aircons, lights etc) 

Edit: On good days, PV generation is 13-16kwh which covers us for a day of washing machine loads, dishwasher loads and pool pump running + both me and the wife working from home. Our usage is approx 18-28kwH depending if we need to use the aircons as well. Gas stove. Geyser is not included in these amounts (as my CT coil was not setup properly)

Edited January 26, 20223 yr by mzezman

11 hours ago, mzezman said:

You can add more batteries after the fact - especially if its within a short period. Hubble, Shoto, FreedomWon, Dyness, Alpha all allow that on the Sunsynk. I currently have a 5kw SS and it works great at blending the PV, Grid and Battery. I have a small PV array (2.4kwp) and will be increasing this in Feb to at least 5kwp. I also have 1 4.8kwh battery and the hope is to increase this by 1 more to take us through the night. Most of my usage is mid morning with another peak in the evening (aircons, lights etc) 

Edit: On good days, PV generation is 13-16kwh which covers us for a day of washing machine loads, dishwasher loads and pool pump running + both me and the wife working from home. Our usage is approx 18-28kwH depending if we need to use the aircons as well. Gas stove. Geyser is not included in these amounts (as my CT coil was not setup properly)

Thanks for the response! Do you have a timeline more or less of what a short period would be? Considering these batteries go for 20-30k (decent size), I'd have to save 4-6 months before I can add another set. I have to make a choice in either buying all the batteries in one go (saving up longer) or if half a year is ok to wait, then I can get started in the meantime. 

I already converted to gas for cooking, so that's sorted 🙂

What I have noticed from a lot of research is that lithium batteries seem to be a lot more tolerant when it comes to mixing batteries of different ages and capacities. Personally I wouldn’t go longer than two years in age difference between batteries. 

What I do to keep my geyser in check is fit a slightly smaller element and add a geyser timer. The geyser only comes on between 11am and 2pm (when solar charging is at it peak for my setup) I also fitted a geyser blanket and cranked the heat up to 70 degrees. This works well for me. 

@FriendlyToast, there is no problem mixing old and new lithium batteries, I have 4.8 kWh battery with a 6500 watt array, works great for me.

Thanks! 

I'll continue reading and researching while saving up, but I think I have all that I need for now, 🙂 Thanks everyone!

On 2022/01/26 at 11:35 AM, Gandalf said:

but spending that much on a geyser that can only heat water is a waste of funds,

100% agree with you hear 🙂
 

I use my PV's excess solar energy and a geyser timer to get it working perfectly in sync

On 2022/01/26 at 12:07 PM, JacoG said:

Hi Friendly,

 

I went exactly the same route as you are mentioning. I splashed a bit and rather got the 8kw Deye inverter, but could only afford 12 380W panels and one 5.1kw battery. We swopped my Geyser's element with a 3kw element and at this stage when the sun is shining properly the battery and PV carries the geyser. I only run my geyser element from 10:00 to 15:00 but most days the Geyser is at 65 degrees by 12:00 this is when my pool pump comes on and run until 15:00. We also swapped our Gas/Electric oven for a full gass one.

My savings so far is around R1500 a month.

Hopefully I can buy another 8 to 10 panels and another battery before winter to run the geyser a bit longer.

 

I would definitely recommend that everyone starts using timers to manage energy requirmentes

Your timer routine sounds pretty much the same as mine: 
+ Pool pump =
ON @ 11h45, OFF @ 15h45

+ Geyser =
ON @ 05h15, OFF @ 06h15,
ON @ 11h30, off @ 16h00

It is an awesome feeling running an aircon off the power of the sun on a hot day 🙂

Just adding my own path to solar, which tried to answer the same questions as the OP's.
I actually did a flat panel Geyser conversion 3 years ago which included the Geyserwise controller. It worked well enough on sunny days.
Now had my Solar installation for 6 odd months and actually have more PV power during the day than I can consume. (sunny days)
My single 5,5kW Battery is usually full by 08:30 - 09:00. My Geyserwise is set to use electric power from 10:00 for 3 hours but hardly ever needs more that 1 hour to go to the max of 65C for the element. On Sunny Days the Flat Plate then takes it to 80C at which stage the Geyserwise disables the circulation pump. So no more hot water shortages ever since. Yes, you are right, if you are going solar, it doesn't male sense to get a solar geyser, rather spend that money on more solar panels for the PV.
My monthly usage used to be 200 to 250kW before I installed the PV solar. Now that I have solar I am not so stingy anymore and probably use 50% more during the day.
The only thing I still need to do for Winter is get another Battery. Currently my SOC at first solar input in the morning is 30-40%, which is OK, but in Winter the nights are 2 hours longer and I don't really want to run the battery lower than 30% SOC on a regular basis.

On 2022/01/26 at 11:35 AM, Gandalf said:

feel free to give me charts on how much better a solar geyser can perform on a cloudy day.

I have 20 tube EV geyser, and 6600kWp solar PV, and on rainy days the 20 tube EV geyser is close to useless, whereas the 6600kWp of solar PV still provides just under 1 kW of power. I've had the 20 tube EV geyser for years before the PV install, and on non rainy days it's great.

If I had the choice again I would go with only solar panels and no geyser EVT. I really think the extra solar panels is more versatile than the tubes.

9 hours ago, RichardZA said:

If I had the choice again I would go with only solar panels and no geyser EVT. I really think the extra solar panels is more versatile than the tubes.

Everyone that I know with a similar setup says exactly the same thing. 

We need to compile a list of "Solar Power Defacto Laws".

1. You can never have enough panels. The vast majority of people increase the number of their solar panels within the first six months of the original install.

2. If you considering an EVT geyser, don't. Rather read defacto law #1.

8 hours ago, YellowTapemeasure said:

Everyone that I know with a similar setup says exactly the same thing. 

We need to compile a list of "Solar Power Defacto Laws".

1. You can never have enough panels. The vast majority of people increase the number of their solar panels within the first six months of the original install.

2. If you considering an EVT geyser, don't. Rather read defacto law #1.

If I get a 8kw inverter, would 8kw worth of panels then be ideal? Might as well plan properly before I officially get started. 🙂

18 minutes ago, FriendlyToast said:

If I get a 8kw inverter, would 8kw worth of panels then be ideal? Might as well plan properly before I officially get started. 🙂

It depends, anything from 8000 to 10400W. It doesn't matter if it does not get done right away, but planning for it is wise, So an optimal mounting layout should be planned, as well as cabling sizes, to ensure less rework and expenses later. Planning for expansion is smart.

Warning: I take things literally. When you say "off grid", do you mean you want to cut the cord completely? If so, you will need either a lot of battery, and thus a lot of panels, or a second power source. 3 years ago I thought I was going off grid, but I found out what a string of overcast days does to system performance. 

Don't get me wrong: I have protection against outages, and I am saving money, but off-grid I am not.

If you're using the term more loosely as in "significantly reducing reliability on grid and wanting protection against outages" then that Sunysynk 8KW is a good place to start.

My system is 4.6 KW, which sounds like a lot. But run the dishwasher, the microwave, the kettle at the same time and you're getting close to that limit. My hot water is on the backed up side as well as it uses a heat pump, not an element. So if that's running and lots of stuff gets turned on in the kitchen then we can have the system trip (and have had). 8KW gives a lot more head room, and you don't have to have rules like I have IE count what's already on in the kitchen, because you can only have two of toaster, kettle, microwave and dishwasher at the same time. 8KW provides a greater chance of people just being able to do what they do.

26 minutes ago, Bobster said:

Warning: I take things literally. When you say "off grid", do you mean you want to cut the cord completely? If so, you will need either a lot of battery, and thus a lot of panels, or a second power source. 3 years ago I thought I was going off grid, but I found out what a string of overcast days does to system performance. 

Don't get me wrong: I have protection against outages, and I am saving money, but off-grid I am not.

If you're using the term more loosely as in "significantly reducing reliability on grid and wanting protection against outages" then that Sunysynk 8KW is a good place to start.

My system is 4.6 KW, which sounds like a lot. But run the dishwasher, the microwave, the kettle at the same time and you're getting close to that limit. My hot water is on the backed up side as well as it uses a heat pump, not an element. So if that's running and lots of stuff gets turned on in the kitchen then we can have the system trip (and have had). 8KW gives a lot more head room, and you don't have to have rules like I have IE count what's already on in the kitchen, because you can only have two of toaster, kettle, microwave and dishwasher at the same time. 8KW provides a greater chance of people just being able to do what they do.

Ah! I actually used it loosely. I do have a generator, but that's going as soon as I start this project. Furthermore, I think hybrid is actually the best to get started and cater for cloudy days. I'm going to do this piece by piece anyway (except batteries, wills ave up and buy everything in one go to not mix old + new)

From what I researched, you can set a preference on Sunsynk to use solar first and supplement with grid. 

1 hour ago, YellowTapemeasure said:

It depends, anything from 8000 to 10400W. It doesn't matter if it does not get done right away, but planning for it is wise, So an optimal mounting layout should be planned, as well as cabling sizes, to ensure less rework and expenses later. Planning for expansion is smart.

Why would I want to add more panels (kw) than what the inverter can handle? Is it for those cloudy days? 

3 minutes ago, FriendlyToast said:

Ah! I actually used it loosely. I do have a generator, but that's going as soon as I start this project. Furthermore, I think hybrid is actually the best to get started and cater for cloudy days. I'm going to do this piece by piece anyway (except batteries, wills ave up and buy everything in one go to not mix old + new)

From what I researched, you can set a preference on Sunsynk to use solar first and supplement with grid.

Yes.  I have a hybrid system, and it's quite configurable. When the weather is fine I have no problems - except possibly if there's shedding about 5 to 6 am when batteries are at their lowest and there's no PV.  Or if there's load shedding and overcast weather. But load shedding happens to a schedule, so if I'm really worried I can force charge the batteries from grid ahead of the load shed. So there can be some management required. Keep an eye on your system early on, learn how it behaves, and you can take any necessary action.

20 minutes ago, FriendlyToast said:

Why would I want to add more panels (kw) than what the inverter can handle? Is it for those cloudy days? 

Correct. To compensate for the days where solar irradiance is not ideal.
Your inverter will clip the excess if and when it exceeds the max.
Also if you can get it, have a look at the panel manufacturers full spec sheet and rather use the NOCT (Nominal Operating Cell Temperature) figures rather than the STC (Standard Test Conditions) as that will provide you with the more realistic output expectations. Worst case scenario.
For example I expected mine to perform as per the STC. Only after I got Solar Assistant was I able to analyse and realise the reason why I have never seen more than 4,9kW from my panels which should provide 6,4kW in ideal test conditions. 

Edited February 20, 20223 yr by zsde

4 minutes ago, zsde said:

Correct. To compensate for the days where solar irradiance is not ideal.
Your inverter will clip the excess if and when it exceeds the max.
Also if you can get it, have a look at the panel manufacturers full spec sheet and rather use the NOCT (Nominal Operating Cell Temperature) figures rather than the STC (Standard Test Conditions) as that will provide you with the more realistic output expectations. Worst case scenario.
For example I expected mine to perform as per the STC. Only after I got Solar Assistant was I able to analyse and realise the reason why I have never seen more than 4,9kW from my panels which should provide 6,4kW in ideal test conditions. 

Thank you. I feel like I need an advanced degree to read that sheet 😅 I'll start doing some research on panels.

Edited February 20, 20223 yr by FriendlyToast

27 minutes ago, FriendlyToast said:

Thank you. I feel like I need an advanced degree to read that sheet 😅 I'll start doing some research on panels.

No need. Here I highlighted the values to look for. It looks intimidating as JA put 6 panel types on one tech spec sheet.
You will see the difference in VoC and IMp and also the PmaxW. Thus I suggest work on the NOCT as that is closer to the real world.

Edited February 20, 20223 yr by zsde