Hi

I'm getting a solar system installed next week.

16x545W solar panels

1x8kw Inverter

5x5.1kw battries

My aim is to minimise my monthly bill.

I have 2 questions around how to cater for loadshedding while still using most of my battery every day to minimise my bill.

Question 1 - How do I allow the system to use battery power when load shedding occurs? I'll me using the Time of use setting and will set that at 100% during the day and 40% at night. But what happens if load shedding happens when the battery is below this SoC (when its still charging up to 100% early morning or when I've used it to below 40% at night)?

Question 2 - If I want to use all battery power each night, what is the benefit of connecting geysers to non-essential load? The downside is that if I have load shedding during the times when I want the geysers to run via the timers I'll have no warm water. Why not just connect them to essentials and set them for the afternoon when I have excess PV and in the morning when they'll either use what battery is left or the grid (if its there)?

Thanks

40 minutes ago, TT5 said:

Question 1 - How do I allow the system to use battery power when load shedding occurs?

It just will, unless the solar side is producing more than the load is needing...

You have a low cutoff setting for the battery, if there's no grid and no solar and the battery hits that low cutoff setting the inverter will shut off.

You have 8kW-odd solar and 25kWh's worth of battery, that should keep you going and depending on your daily consumption and when this consumption occurs, your should be able to run without the grid mostly, only the odd cloudy day, might need some extra energy injected from the grid... but, of course, if your daily consumption is, let's thumbsuck a ridiculous figure of 90kWh per day, then you will still need the grid even on sunny days...

45 minutes ago, TT5 said:

Question 2 - If I want to use all battery power each night, what is the benefit of connecting geysers to non-essential load?

you should not connect the how water cylinder/HWC to the output of your inverter and use the battery to heat up the water, I'd say, you need to use excess solar to bring the HWC even up to 75 or 80°C, if you have that much excess solar, which is quite possible, it all depends on your daily average consumption, either way, at 75-odd°C, unless your HWC is sitting out in the open and without any thermal insulation around it, you probably won't need to heat it up over night.

2 minutes ago, Kalahari Meerkat said:

It just will, unless the solar side is producing more than the load is needing...

You have a low cutoff setting for the battery, if there's no grid and no solar and the battery hits that low cutoff setting the inverter will shut off.

You have 8kW-odd solar and 25kWh's worth of battery, that should keep you going and depending on your daily consumption and when this consumption occurs, your should be able to run without the grid mostly, only the odd cloudy day, might need some extra energy injected from the grid... but, of course, if your daily consumption is, let's thumbsuck a ridiculous figure of 90kWh per day, then you will still need the grid even on sunny days...

you should not connect the how water cylinder/HWC to the output of your inverter and use the battery to heat up the water, I'd say, you need to use excess solar to bring the HWC even up to 75 or 80°C, if you have that much excess solar, which is quite possible, it all depends on your daily average consumption, either way, at 75-odd°C, unless your HWC is sitting out in the open and without any thermal insulation around it, you probably won't need to heat it up over night.

I will definitely heat the 2x geysers up during the day after batteries are charged, let's say sequentially from 14:00-16:00. My problem is that if they are connected to non-essential and I get load shedding during these times they won't run. the way I understand it is you can only power non-essential items, even using excess PV, if the grid is on.

So the idea isn't really to use batteries to run them, the problem is in order to run them with excess PV you'll automatically also use battery power once PV isn't there. Unless I guess you set the SoC so that it doesn't.

What I'm battling with is why can't I run the geysers off the batteries if I still have capacity left early mornings?

7 minutes ago, Kalahari Meerkat said:

It just will, unless the solar side is producing more than the load is needing...

You have a low cutoff setting for the battery, if there's no grid and no solar and the battery hits that low cutoff setting the inverter will shut off.

You have 8kW-odd solar and 25kWh's worth of battery, that should keep you going and depending on your daily consumption and when this consumption occurs, your should be able to run without the grid mostly, only the odd cloudy day, might need some extra energy injected from the grid... but, of course, if your daily consumption is, let's thumbsuck a ridiculous figure of 90kWh per day, then you will still need the grid even on sunny days...

you should not connect the how water cylinder/HWC to the output of your inverter and use the battery to heat up the water, I'd say, you need to use excess solar to bring the HWC even up to 75 or 80°C, if you have that much excess solar, which is quite possible, it all depends on your daily average consumption, either way, at 75-odd°C, unless your HWC is sitting out in the open and without any thermal insulation around it, you probably won't need to heat it up over night.

My daily use is 45kWh. But that was before switching stove to gas and getting timers for geysers. I'll only produce 38kWh at 80% though. So I'll most likely deplete my batteries every day.

8 minutes ago, Kalahari Meerkat said:

It just will, unless the solar side is producing more than the load is needing...

You have a low cutoff setting for the battery, if there's no grid and no solar and the battery hits that low cutoff setting the inverter will shut off.

You have 8kW-odd solar and 25kWh's worth of battery, that should keep you going and depending on your daily consumption and when this consumption occurs, your should be able to run without the grid mostly, only the odd cloudy day, might need some extra energy injected from the grid... but, of course, if your daily consumption is, let's thumbsuck a ridiculous figure of 90kWh per day, then you will still need the grid even on sunny days...

you should not connect the how water cylinder/HWC to the output of your inverter and use the battery to heat up the water, I'd say, you need to use excess solar to bring the HWC even up to 75 or 80°C, if you have that much excess solar, which is quite possible, it all depends on your daily average consumption, either way, at 75-odd°C, unless your HWC is sitting out in the open and without any thermal insulation around it, you probably won't need to heat it up over night.

Sorry, should have read everything before replying. So when the grid is not available, do the system then not limit battery use as per the SoC in the Time of use settings?

1 minute ago, TT5 said:

So the idea isn't really to use batteries to run them, the problem is in order to run them with excess PV you'll automatically also use battery power once PV isn't there. Unless I guess you set the SoC so that it doesn't.

If they are on the non-essential side, then once the grid is gone, there's no power to that side, even if you have excess solar energy... ideally you need to change the heating schedule to try and heat them up before loadshedding happens... otherwise the AUX output was designed for this scenario, have the HWC's on the AUX side and let them draw power, but set the battery limit, to let's say 80%, so, only if the battery is at 80% charge level or higher, will the AUX output have power on it... whether the grid is on or not...

3 minutes ago, TT5 said:

Sorry, should have read everything before replying. So when the grid is not available, do the system then not limit battery use as per the SoC in the Time of use settings?

Nope, there is a setting elsewhere that sets the minimum SOC, where the inverter will switch off, if there is not enough solar and the grid is AWOL and the batteries have reached that minimum SOC...

 

9 minutes ago, Kalahari Meerkat said:

Nope, there is a setting elsewhere that sets the minimum SOC, where the inverter will switch off, if there is not enough solar and the grid is AWOL and the batteries have reached that minimum SOC...

 

Do you know where to find this setting? Thanks for the help btw....

 

11 minutes ago, Kalahari Meerkat said:

If they are on the non-essential side, then once the grid is gone, there's no power to that side, even if you have excess solar energy... ideally you need to change the heating schedule to try and heat them up before loadshedding happens... otherwise the AUX output was designed for this scenario, have the HWC's on the AUX side and let them draw power, but set the battery limit, to let's say 80%, so, only if the battery is at 80% charge level or higher, will the AUX output have power on it... whether the grid is on or not...

Must be honest I've read many negatives about the Aux output... Also doubtful if my installer would know how to do this. Let me perhaps ask why you you think its bad to use batteries for geysers?

If all goes well I'll only do this early morning for a boost. I can always set the SoC to 40% to always have something left for after geysers are done?

So it feels like I've got a lot of battery backup and can manage this effectively.

Other issue I can think of is overloading? But this is only applicable during load shedding right? If I use more than 8kwh when the grid is there the Deye will just pass through grid power to supplement (up to 12kwh I believe)?

26 minutes ago, TT5 said:

Do you know where to find this setting? Thanks for the help btw....

On the SunkenSynk 5k, which is what I have there is, under Battery a Shutdown tab with 3 entries...

Shutdown  20%
Low Batt    25%
Restart       25%

In this scenario a Low battery warning should come up once 25% SOC is reached at 20% SOC, the inverter should shut off its AC output and not come back until the battery has been recharged up to a SOC of 25% or more.

The Deye, being the original, should have similar entries for you to set...

29 minutes ago, TT5 said:

Must be honest I've read many negatives about the Aux output... Also doubtful if my installer would know how to do this. Let me perhaps ask why you you think its bad to use batteries for geysers?

I'd think you'd want as much battery energy available for things that really matter, being able to turn on a Kettle to boil water for Coffee etc. at night, the HWC shouldn't drop that much temperature wise, unless you're a household of 6 and everyone want to run a bath of water, then yes, you got a problem with that... but again, if you can set and monitor the HWC's water temperature, I'd go overboard as soon as there is excess energy and run it up to 80°C, obviously if you're in Gauteng, you will want to be accurate on the temperature reading since you don't want the water to boil, but let's say you're getting out 75°C, you'd need a lot less hot water and lot more cold water to make this lot usable and thus have lots more hot water available.

There were some issues with the AUX initially, I believe, that has been sorted by way of firmware updates, but it should be trivial to check this and ensure all is as expected. I don't have a HWC, only a 100l solar HWC with 12 glass evacuated tubes, so there's a boatload of electrons we never waste on heating water.

As for cooking we used to be mostly gas, now, mostly electric with Induction cooker plate etc. but this is strictly during sunshine and basically never after sunset/off batteries. We only have 8kWh of battery, so about a third of yours...

1 hour ago, TT5 said:

Question 2 - If I want to use all battery power each night, what is the benefit of connecting geysers to non-essential load? The downside is that if I have load shedding during the times when I want the geysers to run via the timers I'll have no warm water. Why not just connect them to essentials and set them for the afternoon when I have excess PV and in the morning when they'll either use what battery is left or the grid (if its there)?

You might be making the same mistake I made when I first bought a solar system. We forget that the sun doesn't shine all the time. In Johannesburg right now we are on a run of overcast days. PV systems won't produce much in these conditions, so be careful of assumptions like "the afternoon when I have excess PV". This afternoon in Jhb there won't be much excess PV.

This is not meant to say that I think I made a mistake or that you should call things off. I don't regret buying that system, but it is not doing every day what I thought it would do. But with some occasional interventions on days like today when it is overcast and there's load shedding and so I charge the battery using grid power, and some personal discipline, we have an uninterrupted way of life and the system is saving us a significant amount on our municipal bill.

On install, your DB will be split into essential and non-essential loads. It is not difficult to move a circuit from one side of the DB to another. So my advice would be to live with the system for a while, watch it and see how it reacts and how far it gets you through a load shed, then if you want to, you can move loads onto the backed up side.

Most hybrid systems will blend the various power sources available to them. So this means that you geysers mostly will run off of PV or battery anyway - unless there is a grid outage. This was the case for me. My main geyser uses a heat pump rather than an element, and I eventually saw that I would have enough battery to be able to run it on the essential side so that it would always run in the morning, and, on most days, the battery would recharge as the sun came up.

So watch your system for a while, note how it behaves, especially during load sheds and when the the weather is overcast, and then you can move circuits over to the essential loads if you feel comfortable to do so.

The other thing to watch out for is too many loads on the essential side running at the same time. If you exceed that 8kw limit, even if only for a few seconds, the system will trip. In my case we were getting into dangerous territory if the heat pump was running, the dishwasher and the microwave were on, and then somebody turned on the kettle or the toaster. This is why your installer is recommending that you don't backup the geysers, he is thinking of worst case scenarios.  

6 hours ago, Kalahari Meerkat said:

On the SunkenSynk 5k, which is what I have there is, under Battery a Shutdown tab with 3 entries...

Shutdown  20%
Low Batt    25%
Restart       25%

In this scenario a Low battery warning should come up once 25% SOC is reached at 20% SOC, the inverter should shut off its AC output and not come back until the battery has been recharged up to a SOC of 25% or more.

The Deye, being the original, should have similar entries for you to set...

Thx, I'll check.

 

And just to confirm again, the Deye will then overrule the SoC % in the Time of use setting?

 

And it will do this when the grid goes down?

5 hours ago, Kalahari Meerkat said:

I'd think you'd want as much battery energy available for things that really matter, being able to turn on a Kettle to boil water for Coffee etc. at night, the HWC shouldn't drop that much temperature wise, unless you're a household of 6 and everyone want to run a bath of water, then yes, you got a problem with that... but again, if you can set and monitor the HWC's water temperature, I'd go overboard as soon as there is excess energy and run it up to 80°C, obviously if you're in Gauteng, you will want to be accurate on the temperature reading since you don't want the water to boil, but let's say you're getting out 75°C, you'd need a lot less hot water and lot more cold water to make this lot usable and thus have lots more hot water available.

There were some issues with the AUX initially, I believe, that has been sorted by way of firmware updates, but it should be trivial to check this and ensure all is as expected. I don't have a HWC, only a 100l solar HWC with 12 glass evacuated tubes, so there's a boatload of electrons we never waste on heating water.

As for cooking we used to be mostly gas, now, mostly electric with Induction cooker plate etc. but this is strictly during sunshine and basically never after sunset/off batteries. We only have 8kWh of battery, so about a third of yours...

Even if I can heat the water during the afternoon, our largest warm water consumption is in the evening. Because the geysers will be off then it will fill or at least half fill with cold water that needs to be heated the following morning in case someone wants to shower.

Can't see how I will get away from a quick burst in the morning, but will certainly check.

My view is that its almost irrelevant whether the geysers are on essential or non-essential. In the afternoons I should have excess PV and in the mornings I'll use battery if still available and if not grid. I'll leave a little battery in case there is load shedding.

Last option is to install gas geyser after electric geyser that can provide burst in the morning.

5 hours ago, Bobster. said:

You might be making the same mistake I made when I first bought a solar system. We forget that the sun doesn't shine all the time. In Johannesburg right now we are on a run of overcast days. PV systems won't produce much in these conditions, so be careful of assumptions like "the afternoon when I have excess PV". This afternoon in Jhb there won't be much excess PV.

This is not meant to say that I think I made a mistake or that you should call things off. I don't regret buying that system, but it is not doing every day what I thought it would do. But with some occasional interventions on days like today when it is overcast and there's load shedding and so I charge the battery using grid power, and some personal discipline, we have an uninterrupted way of life and the system is saving us a significant amount on our municipal bill.

On install, your DB will be split into essential and non-essential loads. It is not difficult to move a circuit from one side of the DB to another. So my advice would be to live with the system for a while, watch it and see how it reacts and how far it gets you through a load shed, then if you want to, you can move loads onto the backed up side.

Most hybrid systems will blend the various power sources available to them. So this means that you geysers mostly will run off of PV or battery anyway - unless there is a grid outage. This was the case for me. My main geyser uses a heat pump rather than an element, and I eventually saw that I would have enough battery to be able to run it on the essential side so that it would always run in the morning, and, on most days, the battery would recharge as the sun came up.

So watch your system for a while, note how it behaves, especially during load sheds and when the the weather is overcast, and then you can move circuits over to the essential loads if you feel comfortable to do so.

The other thing to watch out for is too many loads on the essential side running at the same time. If you exceed that 8kw limit, even if only for a few seconds, the system will trip. In my case we were getting into dangerous territory if the heat pump was running, the dishwasher and the microwave were on, and then somebody turned on the kettle or the toaster. This is why your installer is recommending that you don't backup the geysers, he is thinking of worst case scenarios.  

Thanks

I understand that there will be days when I'll have to use the grid, no issues with that. Best I can do is plan for the good days I guess.

Again my concern with geysers on non-essential side is I'll have to stay on top of load shedding schedules to see when it overlaps with my geyser times as they won't come on during these times. I want to get away from load shedding schedules. So on essential load geysers will use excess PV in the afternoons and battery/grid in the mornings. (On cloudy days it will use battery if there is else grid if there is - can't solve for them if there is none of that anyway).

Does this make sense? Am I missing something?

Wrt the load, can you confirm my understanding? I was under the impression that the 8kw limit is what the inverter can supply form battery/PV, but it can pass through additional power from grid on top of that. So overload only becomes a risk when geyser is on (4kw at most), grid goes off and I use more than 4kw in the rest of my house (unlikely during early morning or late afternoons)?

1 hour ago, TT5 said:

And just to confirm again, the Deye will then overrule the SoC % in the Time of use setting?

The time of use settings will either a: allow the grid to charge and power the load, if the battery % is lower than the ToU setting for the time... or b: run off the grid if the battery % is lower than the ToU setting for the time in question and grid charging is not enable, but if the grid is down, all of the ToU settings go out the window (after all, they are for the grid's power) and the inverter tries to keep the essential side running using PV and battery and the battery settings (Low Battery, Shutdown, Restart) will become relevant, until the grid comes back, then ToU will take over again.

13 hours ago, Kalahari Meerkat said:

The time of use settings will either a: allow the grid to charge and power the load, if the battery % is lower than the ToU setting for the time... or b: run off the grid if the battery % is lower than the ToU setting for the time in question and grid charging is not enable, but if the grid is down, all of the ToU settings go out the window (after all, they are for the grid's power) and the inverter tries to keep the essential side running using PV and battery and the battery settings (Low Battery, Shutdown, Restart) will become relevant, until the grid comes back, then ToU will take over again.

Thx. 

17 hours ago, TT5 said:

Thanks

I understand that there will be days when I'll have to use the grid, no issues with that. Best I can do is plan for the good days I guess.

Lol. Then you're a step ahead of where I was. 

17 hours ago, TT5 said:

Again my concern with geysers on non-essential side is I'll have to stay on top of load shedding schedules to see when it overlaps with my geyser times as they won't come on during these times. I want to get away from load shedding schedules. So on essential load geysers will use excess PV in the afternoons and battery/grid in the mornings. (On cloudy days it will use battery if there is else grid if there is - can't solve for them if there is none of that anyway).

OK.. I don't have a Deye inverter, so take this under advice. 

My system will always go to the batteries ahead of grid. Even for non essential circuits. When the grid is up & PV is low, it will service non essential loads from the battery. 

The Deye has the auxiliary port which you can parameterise, so that may solve your problem. 

17 hours ago, TT5 said:

Does this make sense? Am I missing something?

Wrt the load, can you confirm my understanding? I was under the impression that the 8kw limit is what the inverter can supply form battery/PV, but it can pass through additional power from grid on top of that. So overload only becomes a risk when geyser is on (4kw at most), grid goes off and I use more than 4kw in the rest of my house (unlikely during early morning or late afternoons)?

Again I can only talk about what I have. My system is constantly inverting. And so even when there's loads of PV, if I exceed the limit on the backed up side, the inverter trips. If there is PV or grid it will reboot. 

Again, find out what the Deye does in these circumstances. In my case I learned the hard (but not that hard) way. 

Hi. My system was installed today. I have a question wrt the "Zero export to CT" function on the Deye. This needs to be selected if I want to use excess PV to power non-essentials as far as I understand.

What I see now though is that while I still have battery power available and this is being used to power my home, the DEYE shows that the load is zero. If I switch back to "Zero export to Load" it shows logical nrs again.

Is this the CT that wasn't correctly installed? The installer promised me it was correct. As far as I understood from him he installed it on the DB just after the main switch.

2 minutes ago, TT5 said:

Hi. My system was installed today. I have a question wrt the "Zero export to CT" function on the Deye. This needs to be selected if I want to use excess PV to power non-essentials as far as I understand.

What I see now though is that while I still have battery power available and this is being used to power my home, the DEYE shows that the load is zero. If I switch back to "Zero export to Load" it shows logical nrs again.

Is this the CT that wasn't correctly installed? The installer promised me it was correct. As far as I understood from him he installed it on the DB just after the main switch.

What direction is the arrow on the CT pointing? It should point toward the home/inverter from the grid

Not sure, will have to check. I also get the feeling that it then stops using battery and goes back to grid because the SOC isn't decreasing

DEYE manual shows the arrow should point towards grid?

5 minutes ago, TT5 said:

DEYE manual shows the arrow should point towards grid?

It would be strange if the Deye is different to the Sunsynk. Synsynk arrow is away from the grid. Here is the easy way to know if it is connected the wrong way.....

5 minutes ago, Scorp007 said:

It would be strange if the Deye is different to the Sunsynk. Synsynk arrow is away from the grid. Here is the easy way to know if it is connected the wrong way.....

Thx. I had it the same which makes me think that isn't my problem. I'm not seeing inverted numbers, I'm not seeing any numbers. Any idea why the load would disappear?