Extra panels or Solar Geyser?

[newby_investor]

Are we on the same planet? I do not have close to R30k to spend on a solar geyser. But this is typical snake oil, my current geyser can accept a modification. This modification will cost about R12k and that includes the installation and COC so that the insurance will accept it. Once installed I will include a scan. This will happen hopefully before or after April.

Yes, you do get an R30k solar geyser but they are not the only option on the market so please don't pretend they are. You push really hard for the most expensive options and I suspect it is because you are probably financially incentivized. Please stop pretending that solar is the only solution. It is not, it is expensive as hell and shouldn't be the only answer to every question. Bully sales reflect badly on any company so perhaps look at the alternatives before you attack every single person for trying to do what makes financial sense.

R12k seems suspiciously cheap. All the quotations that I got for pretty much exactly the same thing to be done to my house were close to double that number.

I think we made the point earlier in the thread that solar geysers are fine, but if there's even a possibility that you're going to put PV in, that it's not worth the extra money. OTOH if you aren't ever going to get PV, you're completely right, a solar geyser will save you money in the long run. Probably less than 5 years pay-back.

That being said though, there are potentially maintenance issues and points of failure. You can't exactly turn the sun off shining on evacuated tubes - so you need to keep the (cool) water flowing. Many solar geyser retrofits that I've seen come with a small PV panel and a pump so that the water can keep flowing even during load-shedding.

 

[6174]

R12k seems suspiciously cheap. All the quotations that I got for pretty much exactly the same thing to be done to my house were close to double that number.

I think we made the point earlier in the thread that solar geysers are fine, but if there's even a possibility that you're going to put PV in, that it's not worth the extra money. OTOH if you aren't ever going to get PV, you're completely right, a solar geyser will save you money in the long run. Probably less than 5 years pay-back.

That being said though, there are potentially maintenance issues and points of failure. You can't exactly turn the sun off shining on evacuated tubes - so you need to keep the (cool) water flowing. Many solar geyser retrofits that I've seen come with a small PV panel and a pump so that the water can keep flowing even during load-shedding.

It is not a big system, and it will be professionally done because the homeowner demands a COC so that insurance can cover it. So it has to be done right. As far as I know, the system does have a little solar panel that drives a pump that will circulate the water. The installer does offer an installation warranty and they are good I have used them before when I had to have the geyser replaced.

This is what I can afford. I just think putting as much load as possible on a solar system, sounds like a bad idea. Nothing likes to push to its limits. But with living costs on the up and working hours on the down, I might not even be able to do that.

But mister Snob-Rich may not be able to understand that.

 

[Pegging]

In my opinion, it is foolish to utilize solar power to drive any heating element as it will drain the system and cycle your batteries even faster than they would otherwise cycle.

I am factually investing in solar vacuum tubes. Their value proposition is two-fold. Firstly, even if they only work 50% of the time, I will save a ton of money. My current geyser consumes about 10 to 12 units of power a day. It makes up for 80% of my power bill each month. Secondly, I have a 50% chance of having hot water during load shedding.

I am also considering having a gas water heater installed. This also has two value propositions. First, it can function without any need for solar radiation thus it will function on overcast days and at night. Secondly, it can work independently.

Both the vacuum tubes and gas water heater will cost less than one-tenth then what a solar system will cost. My gas stove has already proven itself invaluable and very cost-effective as I only spend R300 on gas for it each month. This allows me to cook food for a family of 4 all of us are adults on a day-to-day base.

It also allows me to boil water for coffee, and this alone saves a ton of money as an electric kettle can be very taxing on our power bill. Factually I saved over R150 per month on my power bill just on the electric kettle alone. That is half of my gas costs. That is an incredible saving for something so small.

Once Eskom implements its 18.65% it will have a massive impact on our livelihood, as I am on the lower end of the income scale this will have a fundamental and profound impact on how we live our lives.

What do you mean by "factually investing"? And what is the opposite of that?

 

[6174]

What do you mean by "factually investing"? And what is the opposite of that?

I am sorry you failed basic English. Factually investing means I placed down a deposit and am committed. But due to my working hours being cut, it will take longer.

You should go back to your school and ask for your money back. They didn't do a good job.

 

[Pegging]

I am sorry you failed basic English. Factually investing means I placed down a deposit and am committed. But due to my working hours being cut, it will take longer.

You should go back to your school and ask for your money back. They didn't do a good job.

Thanks. I shall see about that rebate.

 

[6174]

This thread is about the Sunsynk/Deye inverters. It's about people who have them or are interested in them.

I'm not following your logic about using solar electricity to drive a geyser being a drain on the batteries.
Using your batteries to drive a geyser will drain them, just like using a stove or kettle on batteries would drain the battery. Using solar on the other hand, implies using the sun.

By all means, don't invest in solar backup exclusively to power heating appliances. If you can't afford that kind of setup, simply get something to power your essentials. If you can afford extra panels, you can't argue that using them to drive a heating element is stupid.

Even a vacuum tube system needs sun to heat the water, and in some cases to circulate that water. When it's been a week of heavy rain, you have to rely on Eskom unless you've spent a load on batteries either way.

After a number of issues with my roof mounted 300l solar hot water system, I'm ditching it for more panels and a traditional geyser. I already heat those 300l from the sun on any given day. It's not connected to my battery but is powered with excess sun and occasionally supplimented with Eskom. The extra panels will help relieve that and provide extra kW in winter.

From what I understand a hybrid system can switch between solar, grid/generator, and its batteries. If grid power is not available and the sun is not adequate, the system will switch over to its batteries. Unless it is intelligent enough to isolate the geyser it will power it via the batteries.

I am not sure what type of PLC it has or how far you can drill down into its settings but unless it can trigger a contactor to isolate the geyser it will consume power from the battery. Having a timer can help with this but A timer is not intelligent enough to know if the sun is out or not.

The only workaround I can see is a day-night switch that can be calibrated. It can then trigger a relay that can trigger a contactor. Contactors as you know can handle a lot of amps and have less chance of failing to work alongside the relay than just the relay on its own. This will prevent the geyser from consuming power from the batteries. But I am sure you can introduce a PLC that can measure the sun via a little panel and it is just a question of programming in a few values. I like PLCs more BUT they are more expensive. But again what do I know? You are the experts.

 

[6174]

From what I understand a hybrid system can switch between solar, grid/generator, and its batteries. If grid power is not available and the sun is not adequate, the system will switch over to its batteries. Unless it is intelligent enough to isolate the geyser it will power it via the batteries.

I am not sure what type of PLC it has or how far you can drill down into its settings but unless it can trigger a contactor to isolate the geyser it will consume power from the battery. Having a timer can help with this but A timer is not intelligent enough to know if the sun is out or not.

The only workaround I can see is a day-night switch that can be calibrated. It can then trigger a relay that can trigger a contactor. Contactors as you know can handle a lot of amps and have less chance of failing to work alongside the relay than just the relay on its own. This will prevent the geyser from consuming power from the batteries. But I am sure you can introduce a PLC that can measure the sun via a little panel and it is just a question of programming in a few values. I like PLCs more BUT they are more expensive. But again what do I know? You are the experts.

Come to think of it, You might be able to just use a small solar panel that can trigger a little DC relay that can then trigger the contactor. This is actually nice because if the little panel doesn't get enough sun to trigger the DC relay it will not turn the geyser on. You can even introduce a overwrite switch or relay when grid power is on. Got to love relay logic... It just solves so many problems.

 

[Stonemason]

Another solution is to get a dedicated PV system for your existing geyser. With installation mine cost roughly R22 000 and it works very well. During the day DC from the two solar panel heats it to 75 degrees and if you need more heating during the night, it will use AC from Eskom. I have found that it very seldom needs Eskom power.

Come to think of it, You might be able to just use a small solar panel that can trigger a little DC relay that can then trigger the contactor. This is actually nice because if the little panel doesn't get enough sun to trigger the DC relay it will not turn the geyser on. You can even introduce a overwrite switch or relay when grid power is on. Got to love relay logic... It just solves so many problems.

I do not think you know what you are talking about. Have you been marooned on an island somewhere for the last 50 years and have just been rescued?

 

[6174]

But a good quality PLC will be able to measure the voltage of your solar panels via a current Sensor and trigger the relay and contactor when it reaches whatever value it was set to. many ways to skin the proverbial cat. The nice thing about the PLC is you can give it a few Sensors and it can check for solar and or grid and if it picks one up it can turn the geyser on or off depending on the parameters.

just a fyi you can calculate voltage if you have known current and watts so yes a current sensor with a good PLC can easily calculate voltage or just use the current as is. It comes down to what you want to do. It is the whole point of a PLC... Program Logic Control... omw.

 

[6174]

It do not think you know what you are talking about. Have you been marooned on an island somewhere for the last 50 years and have just been rescued?

Again you are the expert but damn

Yea whatever, I don't think you know enough to call someone else stupid. There are only so many ways to convert a measurement signal into data and only so many ways to allow that data to control other things. The same is true with voltage switching. There are only so many ways to detect something and allow it to do something. But again what do I know

No wonder homes are burning down.

 

[Pegging]

Again you are the expert but damn

Yea whatever, I don't think you know enough to call someone else stupid. There are only so many ways to convert a measurement signal into data and only so many ways to allow that data to control other things. The same is true with voltage switching. There are only so many ways to detect something and allow it to do something. But again what do I know

No wonder homes are burning down.

If only there was a way that you could monetise that incredible intellect of yours, you'd be able to afford panels and a couple of batteries.

 

[kolaval]

In my opinion, it is foolish to utilize solar power to drive any heating element as it will drain the system and cycle your batteries even faster than they would otherwise cycle.

I would argue that adding the geyser to your solar(and increasing the capacity if need be) would be better.
1. Once the geyser is heated that extra electricity can be used for something else.
2. No modifications to your geyser
3. No vacuum tubes etc on the roof, just solar panels

 

[6174]

I would argue that adding the geyser to your solar(and increasing the capacity if need be) would be better.
1. Once the geyser is heated that extra electricity can be used for something else.
2. No modifications to your geyser
3. No vacuum tubes etc on the roof, just solar panels

100% correct.

But it is a question of cost VS function. If you have the money to install the extra capacity then you win. What I am saying is, don't stress the system. The electrical equipment doesn't like to be stressed. That is why even your inverter comes with a maximum output AND continuous output. For example, it can push a maximum of 10Kw but it can run 8Kw continuously. It has an overload protection of 5 to 10 seconds to compensate for a motor startup but cannot run on continuous overload.

Adding extra solar panels means you have extra charge capacity but again your inverter if a hybrid can only handle so many panels. You can actually overload it. So it is not just a question of "more is better" It comes down to the inverter, charge controller, and continuous input/output limitations.

Also, there are more costs, you need to control when the geyser is consuming power and from what source otherwise a situation can exist that it will drain your batteries.

All hybrid systems, as far as I know, have built-in chargers that can handle only so much. I don't know of any that can separately control something like a geyser BUT if it can then more power to you.

thanks for not being nasty it was cool of you.

 

[6174]

If only there was a way that you could monetise that incredible intellect of yours, you'd be able to afford panels and a couple of batteries.

It is called work. It is amazing but sadly not always financially rewarding. But yea what do I know it is not like I work with this stuff all the time.

 

[Mike Hoxbig]

100% correct.

But it is a question of cost VS function. If you have the money to install the extra capacity then you win. What I am saying is, don't stress the system. The electrical equipment doesn't like to be stressed. That is why even your inverter comes with a maximum output AND continuous output. For example, it can push a maximum of 10Kw but it can run 8Kw continuously. It has an overload protection of 5 to 10 seconds to compensate for a motor startup but cannot run on continuous overload.

Adding extra solar panels means you have extra charge capacity but again your inverter if a hybrid can only handle so many panels. You can actually overload it. So it is not just a question of "more is better" It comes down to the inverter, charge controller, and continuous input/output limitations.

Also, there are more costs, you need to control when the geyser is consuming power and from what source otherwise a situation can exist that it will drain your batteries.

All hybrid systems, as far as I know, have built-in chargers that can handle only so much. I don't know of any that can separately control something like a geyser BUT if it can then more power to you.

thanks for not being nasty it was cool of you.

In the context of the OP this is not relevant. Nor are the costs.

He can safely handle 4 more panels = 1.8 kWp. That's already half of the heating requirement for your average geyser.

We're long past the geyser argument anyway. The issue has been identified, he's not using his system to its full potential. I'm not even sure what this new argument is about now...

 

[Cius]

Company said that they could run as many as 36 panels.
Think I will look at a few extra panels. Appreciate the help. Thank you.

Sorry, not much time to read the whole thread so this may have already been covered, but depends on when you are pulling those extra units. For me I lacked storage. My battery was charged by 12 daily, and the rest of the day the panels would idle. My battery would then drop to my safety level by 8PM and I would pull from the grid a lot before the sun came up. Hence I saved more from adding a battery than more panels. By doubling up my battery storage I went from about 50% self provided to 90% self provided for the same number of panels. 36 panels sounds like a lot for that amount of battery so I suspect you may have the same issue. Problem is if your batteries are more than 6m old its not advisable to add new batteries with older batteries.

So check your production graphs and see what you could do. I also got smarter with my geyserwise. It allows not just time ranges but also temperature. I shower before work and leave home early so I used to turn the geyser on at 4AM to ensure I had hot water. It was heating it to 60 degrees though which pulls a lot of power. Now I heat the geyser to 45 degrees early on and then have it heat up to 60 once the sun is up and the batteries have had a chance to charge a bit. That saved a ton too. Often I still have enough heat in the geyser from the day before that its already over 45 at 4AM and it does not need to even turn on, or it just needs a short burst to get it up to 45 which is plenty for 2 showers tbh.

 

[Tomtomtom]

Reposting from before...

That's a factor, but he's using more grid than he's exporting.

The issue is his SOC is high and he topping up the batteries from the grid. And this is using more than he's exporting.

View attachment 1486849

He doesn't need to buy anything more, just needs to start making better use of what he already has...

Curious, is there a reason why a system would be set up like this in the first place? Battery kept on standby, despite solar PV?

Not sure I'm understanding the export aspect but is that it, the grid is the cheaper battery to be used first in this case?

So then why change the setup at all?

 

[Mike Hoxbig]

Reposting from before...



Curious, is there a reason why a system would be set up like this in the first place? Battery kept on standby, despite solar PV?

Not sure I'm understanding the export aspect but is that it, the grid is the cheaper battery to be used first in this case?

So then why change the setup at all?

The export is not the issue, it's effectively credited to him for use in future. And there's no set time when it needs to be used by. So it's awesome if you do have a spinning disc meter.

The issue is that he's using more grid than he's exporting. And most of that seems to be in the evenings. When his battery discharges due to grid going down, he immediately charges it back up to 90% from the grid, effectively using his grid credit on topping up the batteries, which is wasteful.

By gradually dropping his battery SOC in the evenings to ensure that he's at (say) 40% in the mornings, he can offset this by ensuring that his grid credit purely goes towards running the load.

The other thing to plan for is an extended outage. To ensure that you have enough battery by morning, before adding onto the system, he could install an inverter aircon to run during the evening to improve efficiency. And move the non-inverter aircon to an area of the house that doesn't need to be always on. Or he could run some automation on the existing aircon to switch off when the grid goes down for more than x hours...

 

[newby_investor]

But it is a question of cost VS function. If you have the money to install the extra capacity then you win.

100%. No argument there.

What I am saying is, don't stress the system. The electrical equipment doesn't like to be stressed. That is why even your inverter comes with a maximum output AND continuous output. For example, it can push a maximum of 10Kw but it can run 8Kw continuously. It has an overload protection of 5 to 10 seconds to compensate for a motor startup but cannot run on continuous overload.

Running a geyser from an inverter won't be a stress on the system though. I'll explain why below.

Adding extra solar panels means you have extra charge capacity but again your inverter if a hybrid can only handle so many panels. You can actually overload it. So it is not just a question of "more is better" It comes down to the inverter, charge controller, and continuous input/output limitations.

Yes, true, but no installer worth their salt will install more panels than your inverter can handle. Most 5 kVA inverters, for instance, can handle more than the 8-9 that my small roof can feasibly fit.

Also, there are more costs, you need to control when the geyser is consuming power and from what source otherwise a situation can exist that it will drain your batteries.

If this is a concern, then you set up your geyser on the "non-essential" side.

When you install the solar system, your house gets wired into "essential" and "non-essential". The "non-essential" stuff is basically on the grid, just like the good old days. The "essential" stuff gets powered off the inverter.

Inverters can be configured to use power from their sources in whatever order. The typical one would be:
1) solar
2) grid
3) batteries.
So if there's not enough sun for your needs, they blend in some power from the grid. Batteries are only used during load-shedding.

You can have it the other way, so that solar charges up your batteries, and then batteries power the essential stuff at night, if you really want to decrease your reliance on grid, but I doubt many folks here are doing it that way. It's configurable though.

W.r.t. the "non-essential" stuff, which is typically geyser and stove but you can wire your house up however you please. These inverters have the ability to export to the grid. But they also have a current transformer coil that gets wrapped around the wire coming out of your meter.

So while your non-essential load is powered from the grid directly, the inverter can push any excess solar power leftover from the essential load, to the grid, but it senses the load using the CT coil to make the net current as close to zero as possible. So you can use the excess solar for geyser / stove.

When the grid goes down (i.e. load-shedding), the inverter won't export anything. It won't push power into that circuit unless it detects that there's actually grid available. So you'll never run into a situation where your geyser is being driven by your batteries.

Sure, you could make that choice and over-spec your system and then put the geyser on the "essential" circuits, but almost no one that I am aware of is doing that. You just use a timer to make sure your geyser is only on during the mid-day, and then hot water should stay hot well into the night.

All hybrid systems, as far as I know, have built-in chargers that can handle only so much. I don't know of any that can separately control something like a geyser BUT if it can then more power to you.

The inverter doesn't control the geyser. But it can be controlled from something like a smart-home thing, or even just a simple timer. Then you're taking advantage of the "free" electricity from the sun, while the geyser is on.

 

[Tomtomtom]

The issue is that he's using more grid than he's exporting. And most of that seems to be in the evenings. When his battery discharges due to grid going down, he immediately charges it back up to 90% from the grid, effectively using his grid credit on topping up the batteries, which is wasteful.

By gradually dropping his battery SOC in the evenings to ensure that he's at (say) 40% in the mornings, he can offset this by ensuring that his grid credit purely goes towards running the load.

Okay thanks, but I'm still confused about what the waste in this case is, since the grid credit is worth exactly the same as PV power surely?

So if the batteries were to be run down to 40% by morning, then excess PV would charge them, rather than running the meter backwards.

But how is one better than the other?