Denns

In my mind a gas heater for this purpose is better: middle winter morning heating.

Hehe, yes I'm in SA... No litigation danger. But Barry says the ElonSmart is locked at 65 deg max and there's nothing that can be done. He suggested insulating the pipes cos there's potential losses there... Which I will definitely do.
For now, I'm quite happy with what I'm seeing... Even on a overcast day today, I got 2.7kWh from the panels, so it will probably take a proper miserable day to get nothing out.

I think he is in SA. Lots of people set to 70. Mines been like that for a year now. My plumber recommended it after he did my element and saw the geyser controller I had.
Had 2 kids over in Christmas last year. (9 year old and a 15 year old). They showered without issues and without adult supervision.

This only applies to men. Women are immune to hot water.

I would set solar target to 70. Get as much as the free solar into the geyser. Get a thermo mixing valve if necessary if worried about scalding (we dont have one but it depends on how careful people are).
Change the times the grid comes in to heat the geyser to about 1.5 hours before the first person's showers. And set the grid target to 50, rather than 55. Why? Setting it to come on too early just leads to more standing losses. 50 is also sufficient enough and saves you the electricity needed to get to 55.
Otherwise, congrats and enjoy the savings man.

Thanks Denns. I think my system is currently nicely balanced with the PV pannels, batteries, Inverter sizing for our needs / expectations, with no plans to increase the overall capacity.

Why do you go back to grid at 40%? Seems you can last the whole night. Unless you want the 40% as backup for powercuts? I would run it down to 20% if it ever gets there which it looks like no as the sun is already coming up.

There is no point in saving your batteries as your batteries will degrade from age and not the cycles. I run my batteries down to 40% on a daily and when loads are a bit higher or clouds hit they go all the way to 5%. I guarantee you in 10 years the battery would have the same lifespan running it down to 5% vs keeping it at 40 constantly. SOC is also very inaccurate. My system says 5% but measuring the no load voltage puts it actually at 20%.
Running them to 40% is a poor ROI in my opinion and you are wasting money buying another battery.
6000 cycles means 16 years running down the battery to 0%. And you still have 80% capacity left after the 6000 cycles. Age will kill your battery before the cycles ever do. The BMS will probably kick the bucket before the cells show a hint of capacity loss.

Below are graphs from a " typical" summer day (Oct '25) ....

You have done very well with your system ..... 👍
mmm, so you are up in GP ... I lived there for 30 years of my working life until we moved back to WP (Langebaan) some 8 years ago ... so I'm still adjusting back to the time zone (sun up and down) here ... 🤣
My panels orientation is not the best ..... 9x are on the standing roof facing mostly Northwest to take advantage of the long summer afternoon sun, but that means the wake up "late" in the morning. The 6x string is on a flat roof with very little incline, hiding behind the low wall protruding slightly above the level of the roof. But that is why I oversized with +/- 8kW solar panels for the 7.2 kW Kodak. Also the reason the 9x string gets very close to the max of 450V.
But, I'm very happy with what I have ... it does what I expected (and more) ..... since day 1 for the past 3 - 4 years.
If it was not for the registration issue, I would not have changed anything. I hope to have the same easy / hands-off setup afterwards again and just continue as is ... then I will be happy.

Hi Denns
Yes, geyser start @ 6am in the morning.
We are in Langebaan, so for us the 8am PV is "normal" for this time of the year with the way my house is build. I do have a little "shading" on one corner of panels with sun rise due to another roof. The house was orientated to give max wind protection, not for solar harvesting unfortunately.
We all have solar for different reasons .. mine back then was to have power 100% of the time during the peak of loadshedding. I had home office working 24/7 for an international company and the little mobile UPS just could not cope anymore. Because I went the full solar solution, I obviously also looked to reduce the Escom as much as "comfortable" for us ... not what would be absolutely possible. We made very few life adjustments, mostly just scheduling the heavy load tasks in and around the house so as not to overload the inverter or batteries. I also like the fact that with the system as is (incl SA automation), I could set it up and forget about it ... everything being taken care of automatically. I would have days on end when I don't even look at the solar. Having said all that, I did adjust the scheduling of the base load of things during the early days of having solar ... so a "normal" day goes as follows:
6am, geyser start. 10am, swimming pools start. 2:45 pm swimming pool stop. 3pm geyser start again (I do have the geyserwise controls etc to control) Looking at the graph above, those little 1kw blips are my coffee machine (don't count) .... +/-5pm was the microwave and the slight reduction at 12 pm was when we went to bed.
The house base load (the whole house is running through the inverter) during the night (before and after solar) was less than 0.5kW/hour before the de-humidifiers ... since adding them that has gone up to +/- 0.9kW during the night.

With all the above etc .... it is normal for us to get through the day in Summer with zero Escom, but in Winter we have the 6am Escom use for the geyser. For me that was / is good enough. It is only me and the wife in the house.

Obviously, when the kids visit, we use a lot more power and then we also use Escom more .... but that is understandable.

True.
I upgraded my tiny 5K system from 10.5kWh to 32kWh storage, the difference in the past 4 months has been remarkable, as is my quality of life:

I assume the blip in grid usage between 6 and 8 is geyser? Does look much better from grid use perspective vs your previous post.

I see your solar starts generating after 8. Any reason it's a bit late to start? Is there shading? Otherwise, it does look good and looks like you can lower your bills now much more than before and fully capitalise on your installed system.

I think the way you have it now is okay. Experiment on your end to see if you can use up to 10%, not daily but for cases where there is a power outage in the morning and you want to still have power till your solar starts generating. You can just manually set it to 10% and power whatever you want. Otherwise as a daily thing I think 20% is best and leaves you with some extra for power outages. Hopefully your area isnt hard hit with them. Loadshedding is pretty much gone so priority should be saving as much and not using the grid.

And you can run the math, if the payback for adding an extra battery is less than 5 years then I say go for it. If it requires replacing your whole bank then the ROI will probably not be worth it. I would run as is, wait for a battery to give issues and then consider replacing with a bigger bank. Until then, just fully utilize what you have and limit grid usage as much as possible.

You might even find ways of running the house more efficiently at night. Simple things as solar light, better efficient lights, turning off things that are unnecessary, replacing that old fridge that only has sentimental value (new fridges are very very efficient) etc. You can make it a little side quest to see where you can shave just 100 to 200W of baseload and you will find yourself having an extra 10 to 20% battery in the morning. Shaving load is free vs spending close to 60k for a bigger battery bank. There is heatpumps, dozens of ways to go about this.

A bit off-topic, but some time ago I decided to go clean the Kodak 2x external "filters" situated at the top sides of the inverter. I found they were not particularly dirty (inverter is installed in my garage) Below graph clearly show the benefit of cleaning regardless ....

Thanks Denis. The 40% is a carry over from load shedding days, wanting to still have some backup in the morning in the event that we would not have Escom. I also thought not to “work” the batteries to the max, but I have been looking at that also without deciding finally. I think you made up my mind for me …. Will run them to 20% and see how it goes first.

Thanks

The inverter is good. My Dad runs his house off grid with it. You can add solar panels to it later when you are ready. Don't know what battery it comes with brand wise, but the battery will be good enough for you. Around 15 hours if you keep the load around 200 to 300W which TV and laptops are somewhat there.

Personally I would go for the ecco as it allows the home to become a solar house in the future. Its a 6.2kW inverter with capacity to take about 6kW of panels. It retails for 5k more than the Hinen. The Hinen you are stuck having a UPS with poor resale value when you want to go the solar route and start saving on the bill later on.

Why consider hybrid inverters if you don't need them?

You make a good point, I was seeing it as an off-grid portable point solution, and it can only function as an off-grid inverter if it is Franken-monstered into a "solar house". Not impossible, but potentially troublesome.
It's still overpriced though, compared to the far more extensible and feature-rich the Hinen / Knyee combo at R18,342.50:
11.4kW solar input vs 6.5kW ;
2x low amperage MPPT vs 1x high amperage MPPT;
Parallel capable;
Hybrid connection possible vs off-grid;
Integrated Type II DC SPD & Type III AC SPD (amazing!);
Built-in aerosol fire extinguisher;
10-Year Warranty vs 5 on inverter only.

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I didnt have experience with solar before we got the house but did get lucky in that the house can take 28 panels from the measurements I took. Currently my 12 panels are sitting on the garage roofs which dont have the best orientation to be honest but I am offgrid with how it is now. It was very easy to do the DIY install on the corrugated roofs they have than deal with the tiles on the house.

I can add another 16 to the house roof but will get a professional to come do it as it does get hot up there and have no interest in going through that exercise again. The orientation there is much better and will generate way more if I did. These are plans for the long long future though.

You reminded me of something quite important, which I forgot: Whilst house-hunting during 2019, I made a point of only viewing properties with:
a clear W-->N<--E view; and
0 degree azimuth (10-15 degrees max either side); and
a roof that can take 24+ panels.
I did not have to look long for a suitable home, and having made my wishlist upfront helped a lot.

That's a great setup. Similar Journey to what I took also. We got the house in 2024 so right off the bat we got the most efficient items we could. We have 2 fridges, one outdoor by the pool house and a much bigger one indoor. Both Hisense and I kid you not when the big one runs it registers as 60W on the app. It uses nothing pretty much.

Only thing I need is the aircons but everything else is similar to you with Gas stove and Gas heaters. Might even add a 15kWh LFP battery in the next 2 years. No extra panels as I already generate much more than my consumption but that battery would allow life to continue without needing to switch off pool pump and fish pond during 3 days cloudy days.

I have a Sunsynk 5K, 6kWp on roof since 2020, and recently upgraded storage to 32K Hina (Knyee white-label), been off-grid since January 2026. I have been optimising usage and current drain over the past 6 years:
Outdoor heatpump for hot water;
Gas stove, oven is still AC, but I built a Pizza oven outside (and a whole outdoor kitchen too!);
Added 2x Inverter aircons (24000 + 18000 BTU);
Gas heater;
Slowly migrated current hungry devices, like firewall / router / NAS / security cameras / NVR to fanless low current models;
Don't operate Class-A amplifiers continuously, or moved to Class-D.
Next on the list is the fridge freezer, eyeing a Bosch AAA+ model.
Optimising a power budget is basically the same as running a bank account: You either create more income, or you cut / replace expenses, or a combination.

Yeah, and I suspect that’s why it’s relatively efficient. From first light the geyser is already getting heated. Every watt goes into the geyser. And no management needed.
Different to using an inverter as if Pv is low and battery is dead then the geyser gets nothing.
The last 2 days had bad weather in JHB. The only thing I had to worry about was my battery charging. I didn’t have to choose between geyser and batteries. This is especially important for me being offgrid without a generator.

The controller uses a timer to determine whether to use AC or DC. Any timer of your choice will work. If its input sees AC it bypasses PV and uses AC only. When your timer goes off and its input doesn't see AC, It switches to PV. So during non PV times you can use AC if you manage to finish all the hot water at night. During the day, your timer will be off to let the PV be the only source to heat the geyser. That's basically how it works.

The DC is not converted to AC. Its a high frequency pulse DC from the panels to allow it to work with your standard thermostat.
Your thermostat controls the heating. If the geyser is up to temp and you have the thermostat set at 55 (should be 70 to maximise solar) then when the thermostat opens the controller idles until the thermostat opens again. Same as when your geyser is being supplied by the grid.
Your next question, if you have a 2kW element the controller will feed whatever is available (whether its 200W or 1500W etc) to the element. The element doesnt care or know what its getting. A 2kW element operates at that power when it sees 230VAC. The resistance is fixed at 26.45 ohms. If you lower the voltage then the power it pushes into the geyser is lowered also. You cant go over 250 or so otherwise you burn out the element. That is why I have 1.34kW of panels and my geyser still gets heated. The element is running at half its rating pretty much.

Because of the above that is why I said I will be able to get more out of a 3kW element than a 2kW because a 3kW element has a resistance of 17.6. So if your panels have a voltage of say 150V, your element can operate at a higher current than if it was at a higher resistance. So with a 2kW element like I have now I am only getting about 66% of the power that I would otherwise get from a 3kW at the same voltage. By that reason that is why Geysertech has 2 controllers, I have the cheaper one which is designed to a max of 3kW elements. The bigger brother goes as high as 4kW elements and takes more panels and have temperature monitoring etc.

Hopefully this answers your questions.

Oh I didnt see this.

450 includes the geyser yes. So my House uses about 250kWh which is on the 2 inverters and battery banks. The geyser averages 200kWh a month.

To cover 450kWh isnt hard to be honest. My personal take though is aim for at least a 8kW inverter, About 6kWp of panels (10x600W or 10x590) and 10kWh of battery. If the geyser is on your Elon then you can drop the panels for the house to 4kWp, a 6kW inverter with good passthrough capabilities (A Solis or Lux power) and still keep the 10kWh of battery.
I have seen solar ways sell packages like these for 50k or so . The 8kW systems typically go for 60k or so. Installation is typically around 15 to 25k. A quote a friend of mine sent recently was for 85k. It was a 8kW Deye inverter, 10kWh of batteries but can't remember the panels.

My entire offgrid installation was 85k. This included the 3.6kW inverter, 5kW inverter, 12kWh of GEL batteries, 5kWh of Lithium battery, 8x650W panels, 4x340W panels, the Geysertech. All the extras like cabling, breakers, DB etc is included. Along with replacement of lights etc.