Sunsynk 5kW setting “Sol exp bat full”

[LoganD]

Hi, can someone explain to me what the “Sol exp bat full” setting does in the Sunsynk 5kW System Mode setting page please?

It falls under “Zero Export”, which I have checked (with the CT coil), so do I need to have the above one checked if I want my solar to be exported to my “local grid” non-essentials like geyser and oven after the battery has reached it’s charge limit, or does it do that automatically with the Zero Export checked?

[Achmat]

1 hour ago, LoganD said:

Hi, can someone explain to me what the “Sol exp bat full” setting does in the Sunsynk 5kW System Mode setting page please?

It falls under “Zero Export”, which I have checked (with the CT coil), so do I need to have the above one checked if I want my solar to be exported to my “local grid” non-essentials like geyser and oven after the battery has reached it’s charge limit, or does it do that automatically with the Zero Export checked?

Can you share your system mode screens. The "Sol exp exp bat full" will export solar to the grid if the batteries are full. It should be unchecked if you don't want to feed into the grid which might trip your prepaid meter if you have one. 

What you want to check is zero export only. This will export any excess pv to loads before the inverter provided the CT coil is installed correctly and in the right place. 

[LoganD]

19 hours ago, Achmat said:

Can you share your system mode screens. The "Sol exp exp bat full" will export solar to the grid if the batteries are full. It should be unchecked if you don't want to feed into the grid which might trip your prepaid meter if you have one. 

What you want to check is zero export only. This will export any excess pv to loads before the inverter provided the CT coil is installed correctly and in the right place. 

Cool, I thought that might be the case, see the attached System Mode setting. The thing that was confusing me is that the "Sol exp bat full" setting is nested under "Zero Export", which to me seems incorrect, because you could technically have "Zero Export" and "Sol exp bat full" checked, which would be contradictory, would it not? To me the way it is laid out seems like if I wanted to export solar via the Grid input/output port, I would have to select "Sol exp bat full", and then additionally, if I wanted it to stay only in my local grid (non-essential in my drawing), I would then have to select "Zero Export" as well, is this a possibility?

I would have tested this myself but unfortunately I wasn't there when my system was installed and they forgot to take the geyser off the essential loads. This should be fixed by next week, so I will do a proper experiment and report back here.

[Tariq]

Hi @LoganD, I am planning to switch the geyser from non-essential to AUX, this way the geyser will switch on and off automatically depending on available solar production.

[LoganD]

Hey @Tariq, ye I've also thought about doing this, I have a few questions regarding that setup if you don't mind.

1. What happens if I have a 4kW geyser element but only 2kW solar (soon 3.2kW), will the element still turn on? I believe you can supply less than the required power because it is a resistive element, but is there anything extra you need to do to allow the element to only receive 2kW and still "turn on", or will it passthrough 2kW from the grid?
2. Do you know if there is a way to have the geyser on non-essential AND/OR aux, so that I can use the grid to top-up at 4kW when its there, but to still be able to use the solar to heat when load-shedding?

[Tariq]

Achmat knows more than me as all his loads are ONLY on the essential circuit, so I will let him answer that question, I however changed to a 2 kW element, which is working great.

 For your second question, you can use a Hagar SFT 240 two pole changeover switch to switch manually between grid and AUX, did I understand you correctly 

[Achmat]

1 hour ago, LoganD said:

Hey @Tariq, ye I've also thought about doing this, I have a few questions regarding that setup if you don't mind.

1. What happens if I have a 4kW geyser element but only 2kW solar (soon 3.2kW), will the element still turn on? I believe you can supply less than the required power because it is a resistive element, but is there anything extra you need to do to allow the element to only receive 2kW and still "turn on", or will it passthrough 2kW from the grid?
2. Do you know if there is a way to have the geyser on non-essential AND/OR aux, so that I can use the grid to top-up at 4kW when its there, but to still be able to use the solar to heat when load-shedding?

Don't know how geyser elements work but the inverter will draw the shortfall from the grid if the grid is available. 

 

I'm not sure if the geyser will turn on if the grid is down and you only have 2kw of excess pv to send to the aux output. Would be an interesting test provided you ONLY have the geyser on the aux and nothing else. 

[Achmat]

1 hour ago, LoganD said:

Cool, I thought that might be the case, see the attached System Mode setting. The thing that was confusing me is that the "Sol exp bat full" setting is nested under "Zero Export", which to me seems incorrect, because you could technically have "Zero Export" and "Sol exp bat full" checked, which would be contradictory, would it not? To me the way it is laid out seems like if I wanted to export solar via the Grid input/output port, I would have to select "Sol exp bat full", and then additionally, if I wanted it to stay only in my local grid (non-essential in my drawing), I would then have to select "Zero Export" as well, is this a possibility?

I would have tested this myself but unfortunately I wasn't there when my system was installed and they forgot to take the geyser off the essential loads. This should be fixed by next week, so I will do a proper experiment and report back here.

It can be confusing but I don't think it will save the settings if you select both. I have tried. 

[LoganD]

25 minutes ago, Achmat said:

Don't know how geyser elements work but the inverter will draw the shortfall from the grid if the grid is available. 

Are you talking about on the aux port here? I have a 2kW heat pump so I might be able to move that onto the aux port, although because it has a compressor it doesn’t like to be turned off and on continuously (apparently), do you know if you can control that aux output somehow to run for certain periods (similar to System Mode) or am I reaching too far here? xD

[Achmat]

3 minutes ago, LoganD said:

Are you talking about on the aux port here? I have a 2kW heat pump so I might be able to move that onto the aux port, although because it has a compressor it doesn’t like to be turned off and on continuously (apparently), do you know if you can control that aux output somehow to run for certain periods (similar to System Mode) or am I reaching too far here? xD

Yes you can.

First option is that it will allow the aux to be permanently on if the grid is available.

If the first setting is deacativated then it will rely on the following two setting.

PV power. You can specify at pv power point you want the aux to switch on. you can set this as high or low as you need. if your base load is only 1.5kW then you could set it to turn on the when pv generation reaches 1 500W. It will switch off as the sun sets and pv production goes under this value.

Aux off battery would be the minimum SOC the battery reaches before the aux is switched off. This to avoid using all your battery for the geyser. You could set this to something like 85%.

Aux on battery would be the point that it will switch the aux. This could be at 100% or any other amount higher than Aux off amount.

It wouldn't be switching on and off every hour. It would basically switch on in the morning as pv production increases and then off again late afternoon. Only on eratic pv days due to clods you could have a few starts and stops but the battery should then decide to switch on and off. If you have a bad solar day and batteries are below 85% based on the example above, it will not switch on and off and only switch on when batteries are 100% and pv is more than 1 500W.

[LoganD]

@Achmat Hey that's amazing! This device continues to impress I must say, and thanks for all the info, really appreciate it!

[Tariq]

First option is that it will allow the aux to be permanently on if the grid is available.

@Achmat, sorry to bug you, does the above sentence mean that it is the same as being connected directly to the grid and that on a bad solar production day, I would just tick the “ Grid always on “ box and the geyser would have Grid power

 

 

 

 

 

[Achmat]

4 minutes ago, Tariq said:

First option is that it will allow the aux to be permanently on if the grid is available.

@Achmat, sorry to bug you, does the above sentence mean that it is the same as being connected directly to the grid and that on a bad solar production day, I would just tick the “ Grid always on “ box and the geyser would have Grid power

 

 

 

 

 

So if you have it ticked then the aux will send power to loads on the aux output if the grid is available. The geyser obviously has its own element that will switch on and off as required. 

This power it sends to the aux would come from available solar first during the day and from the grid at night. 

On bad solar days it will then rely on the grid to power the aux loads. 

 

[Tariq]

As @LoganDsaid, it really is an amazing inverter.

[LoganD]

22 hours ago, Vassen said:

for 1, if it’s a 4kw element, it will use 4kw. It’s basically a resistor and a resistor connected across a voltage... in this case 240v, will result in 4kw being used. I would recommend changing it to a 2kw element. It’s relatively cheap and straightforward to do and your inverter will be able to handle the loads a lot easier. It will obviously take a little longer to heat the water though. 

@Vassen Is it really so cut and dry? If the inverter can limit the output power to say 2kW on the aux port, with a fixed voltage of 240V and fixed resistance of the element, would it not just limit the current into the element, so still heat it, but at half the power rating? There seem to be other options with "phase angle control" which can achieve power limiting, like this device, which works similarly to a LED dimmer I believe. Basically the same price as 2kW element from Geyserwise, but at least then I could still connect the element to the non-essential side and switch between 4kW and 2kW when I want...

Edit: the manual seems to suggest that Solar Power setting in the Aux settings page is a power limit (see pics below), limiting the MAX power to the aux load, not the switch on power as suggested by @Achmat above. So what would happen if I set this to 2kW and then just attached my 4kW element, would it trip the inverter/aux port? Or would it just draw the 2kW which is what I am attempting to achieve?

 

Edited January 27, 2021 by LoganD
Added info

[Achmat]

1 hour ago, LoganD said:

@Vassen Is it really so cut and dry? If the inverter can limit the output power to say 2kW on the aux port, with a fixed voltage of 240V and fixed resistance of the element, would it not just limit the current into the element, so still heat it, but at half the power rating? There seem to be other options with "phase angle control" which can achieve power limiting, like this device, which works similarly to a LED dimmer I believe. Basically the same price as 2kW element from Geyserwise, but at least then I could still connect the element to the non-essential side and switch between 4kW and 2kW when I want...

Edit: the manual seems to suggest that Solar Power setting in the Aux settings page is a power limit (see pics below), limiting the MAX power to the aux load, not the switch on power as suggested by @Achmat above. So what would happen if I set this to 2kW and then just attached my 4kW element, would it trip the inverter/aux port? Or would it just draw the 2kW which is what I am attempting to achieve?

 

You are correct and it's the max power sent to the aux output. 

I have nothing connected to my six so can't test out your theory. 

[LoganD]

@Vassen @Achmat So, I'm not sure why I was fixated on the 2kW from geyserwise, but took your suggestion and just went with a normal 2kW element  so simple, thanks!

I now have another issue, I'm wondering if you guys can help with. So that "Sol exp bat full" setting does seem to be important. I turned my oven on (non-essentials) while there was plenty of sun and no other loads with and without that setting, and you can see from below that it needs to be checked to export your solar to the local grid. Now my issue is that it is not using the batteries to also supplement the local grid, even though I've said that the batteries can drop to 70% (this was between 11:30 and 13:30).

Am I missing a setting somewhere? I thought the Zero Export setting + the use of the timer would do this for me? Do I need to check the "Grid" option? I thought that meant to "charge from grid to 70%", is that wrong?

No export: (10:30 should read 11:30, old image)

With export:

[Achmat]

9 minutes ago, LoganD said:

@Vassen @Achmat So, I'm not sure why I was fixated on the 2kW from geyserwise, but took your suggestion and just went with a normal 2kW element  so simple, thanks!

I now have another issue, I'm wondering if you guys can help with. So that "Sol exp bat full" setting does seem to be important. I turned my oven on (non-essentials) while there was plenty of sun and no other loads with and without that setting, and you can see from below that it needs to be checked to export your solar to the local grid. Now my issue is that it is not using the batteries to also supplement the local grid, even though I've said that the batteries can drop to 70% (this was between 11:30 and 13:30).

Am I missing a setting somewhere? I thought the Zero Export setting + the use of the timer would do this for me? Do I need to check the "Grid" option? I thought that meant to "charge from grid to 70%", is that wrong?

No export: (10:30 should read 11:30, old image)

With export:

It should be taking from the batteries to cover the shortfall.

I will need to check my other screens but can only do so when I'm home.

[LoganD]

1 minute ago, Achmat said:

It should be taking from the batteries to cover the shortfall.

I will need to check my other screens but can only do so when I'm home.

I also thought so, but it's still pulling 1.3kW from the grid while the batteries are at 100%.

Do you think it is an issue with the inverter, should I send this to Sunsynk support?

[Achmat]

1 minute ago, LoganD said:

I also thought so, but it's still pulling 1.3kW from the grid while the batteries are at 100%.

Do you think it is an issue with the inverter, should I send this to Sunsynk support?

Are you on the latest software versions?

[LoganD]

1 minute ago, Achmat said:

Are you on the latest software versions?

Not sure if this is latest? (5kW)

Protocol Version：V0.2.0.1

Control Software Version 1：V2.1.3.7

Communication CPU Software Version：VE.4.1.0

[LoganD]

5 minutes ago, Vassen said:

It should work as you have explained. You don’t need zero export when bat full enabled. 

Hmm, maybe I'm misunderstanding something here, but I thought "Zero export" was to stop export to the "main grid", i.e. before the current clamp, which is what I want (on a prepaid meter).

But from the testing I did it seems I need to check "Sol exp bat full" for it to export the excess solar to my "local grid", i.e. oven and other non-essentials.

So to get solar into my oven it seems I need "Zero export" + "Sol exp bat full" checked, but it's not sending my batteries into my oven, and I'm not sure it ever has...

1 minute ago, Vassen said:

maybe ask to be upgraded to this version

Cool, will do, thanks!

[LoganD]

2 minutes ago, Vassen said:

Are you sure your CT clamp is on the main incoming feed?

Yup, you can see from the flow chart that the oven is pulling 4kW from after the clamp but before the inverter, so the clamp is definitely on the mains coming in.

Are you sure that your solar is going back into the non-essentials, and its not all just coming from the batteries? Because if you look at my pics it definitely stopped exporting solar to my non-essentials without that "Sol exp bat full" setting checked...

Also, why do you have "Grid" checked, do you want the grid to charge the batteries? Is that for in case of load shedding and the batteries drop to below say 50% at 01:00, then the grid charges it back to 50%?

[Achmat]

31 minutes ago, LoganD said:

Yup, you can see from the flow chart that the oven is pulling 4kW from after the clamp but before the inverter, so the clamp is definitely on the mains coming in.

Are you sure that your solar is going back into the non-essentials, and its not all just coming from the batteries? Because if you look at my pics it definitely stopped exporting solar to my non-essentials without that "Sol exp bat full" setting checked...

Also, why do you have "Grid" checked, do you want the grid to charge the batteries? Is that for in case of load shedding and the batteries drop to below say 50% at 01:00, then the grid charges it back to 50%?

Yes to grid charge.

 

i will also change my settings when we have load shedding for grid charge to bring it up to 50%. It will only really do this if there was not enough solar for the batteries to recover.

[LoganD]

Sunsynk support is pretty great, they did my upgrade last night! It is now pushing power from solar and battery to the non-essential loads, without the “Sol exp bat full” setting, and after some more testing yesterday that setting was tripping my Conlog meter almost immediately.

I’m now having the issue that the feedback from oven switching on/off is tripping my meter  I have Zero Export Power set at 40W, but it’s still doing it. When watching the system flow page while the oven is at temperature and the element switching on/off, I can see sometimes upwards of -1000W going into the grid, which is surely going to cause issues. It’s annoying because I can’t have the grid switch off and turn the oven off while I’m trying to cook something, so the non-essential feedback might be dead in the water.

Is it possible that if I put my geyser on the AUX it will be able to absorb the feedback? Anyone else having these Conlog tripping issues? Do I just need to set that Zero Export power higher? Would prefer not to waste 2.4kWh a day just to keep the oven from tripping. Anyone had any luck with convincing the municipality to give the token to turn off reverse flow detection?