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Advice on new System


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Hi Everyone,

 

I am in the process of buying a new home in Pretoria area moving in beginning of April.

I want to get a solar system in the new house. The property also has a flat where my parents will stay currently, we use about 1400kwh a month and there is 2 geysers. Planning on getting the geysers changed to solar in the future when I have saved up some money again.

 

So, I wanted to check do you think my system that I am planning will be big enough, and have a few questions hoping to clear up. The stoves both will be on gas. The ovens are still on electricity but will not be used every day.

System I am planning on as follow.

24 x 440w Mono panels

1 x 8KW/48V Deye Sunsynk Hybrid Inverter

1 x Freedom Won Lite Home 15/12 LiFePO4 Battery 15kwh @90% DOD

 

1.       Should I rather go for 2 x 5kw sunsynk inverters that could help as backup if one might fail, I was thinking that the 8kw might not be big enough for both households?

From my understanding is that even though I might use more than 8kw the inverter can still use the passthrough mode to supplement anything over 8kw so only using the excess from the grid?

2.       I want to oversize the Solar Pv array for days that weather is not so great, hence the reason why I chose 24 x 440 = 10560w is this a good idea? I also see that the max solar input is only 10400w will this be a problem if its slightly over will the inverter only limit up to 10400w or will it damage the inverter.

3.       If the solar array produces more than the 8kw that the inverter can produce will the extra go to waste?

4.       The supplier quoted me on the 15kw freedom won, I believe they are good batteries, will I be.

able to add more to this battery with smaller ones of the same brand?

5.       Will I have to put the geysers on the non-essential load for now until I have the solar geysers up?

Thanks for the help and input.

 

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18 hours ago, Frost said:

1.       Should I rather go for 2 x 5kw sunsynk inverters that could help as backup if one might fail, I was thinking that the 8kw might not be big enough for both households?

There are pro's and cons. I do like the idea of two inverters, but I didn't want the additional expense. But if you can do it, definitely.

18 hours ago, Frost said:

From my understanding is that even though I might use more than 8kw the inverter can still use the passthrough mode to supplement anything over 8kw so only using the excess from the grid?

It will max out at 8.8 kW with all sources blended. I am in the same situation, two houses (cottage for my parents). The 8 kW Sunsynk if more than adequate to run our loads. The one remaining electric geyer runs on a timer on solar and it works fine. On cloudy days the inverter blends Eskom with the solar.

18 hours ago, Frost said:

2.       I want to oversize the Solar Pv array for days that weather is not so great, hence the reason why I chose 24 x 440 = 10560w is this a good idea? I also see that the max solar input is only 10400w will this be a problem if its slightly over will the inverter only limit up to 10400w or will it damage the inverter.

As long as the Voc on the solar strings don't exceed the interter rating it should be fine. Current will be clipped if it exceeds the inverter rating. We only have 4.5 kW of panels, and thats perfect for clear days, but we do fall short on partly cloudy days. My next upgrade will be another few panels. I think with more than 10 kW you should be good to go.

18 hours ago, Frost said:

3.       If the solar array produces more than the 8kw that the inverter can produce will the extra go to waste?

The solar system only produces as much as the load you can put on it. So if the batteries are full and you don't have load, the energy goes to waste. Also, the batteries will charge at their max rate, in the case of my Dyness I am limited to 7 kW on the four batteries.

 

18 hours ago, Frost said:

5.       Will I have to put the geysers on the non-essential load for now until I have the solar geysers up?

Thanks for the help and input.

 

You can do that, or in my case I just used a CBI Astute wifi timer to time the geyers.

It is probably better to run it on the Aux output so the inverter can power down the geysers if your charge gets too low on a cloudy day. However, the Inverter will keep Aux load on while the battery has sufficient charge, so I still suggest adding a timer. You do not want the electric geysers to ever take charge from the battery. The same with the oven. I have limited the battery discharge in the evening so when the oven is in use a little bit of battery is blended with Eskom to feed the oven. The oven is on the grid side, so if Eskom fails, the oven stops working.

 

The above is my work in progress. More panels are in the works, from 4.5 kW to 6.9 kW, and perhaps one more battery, 14.4 kW to 18 kW, then I think my system will be sufficient for my needs.

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Hi Paul , thanks for your input much appreciated.

1.Well it adds about +- R8k if I use 2 x 5kw inverters I just want to get it right from the start, so I do not need to change inverters in the future, I will rather add than to change the setup. What would be the cons of having 1 x 8kw or 2 x 5kw inverters? But if I have the geysers converter to Solar, I believe the 8kw will be more than enough?

2.If you say it would max out at 8.8kw what happens if the grid is on and I would use more than the 8.8kw? From what I read and understood is that anything more than 8kw if grid is available will use passthrough and supplement anything over 8kw up until 90A = +-20kw total?

3.For the oversizing I believe that solar array only produces around 80% of the rated depending conditions etc. so that would get me closer to the 8kw the inverter can supply, on your 4,5kw of panels what average kwk would you get ?

4. The house also have 5 Ac units, if extra power is available after batteries are full, I would like to throw it at the ac units or geysers

5.I will have a look at the CBI Astute wifi timer for the geyser thax a lot, yes would like to have the geysers only come on during the time when the sun is up.

I still need to find alternative to the ovens not sure what’s available, my mom likes to bake :D

Do you also use the sunsync inverter on your setup and how much kw do you produce on average per day with your 4.5kw panels?

 

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10 minutes ago, Frost said:

Hi Paul , thanks for your input much appreciated.

1.Well it adds about +- R8k if I use 2 x 5kw inverters I just want to get it right from the start, so I do not need to change inverters in the future, I will rather add than to change the setup. What would be the cons of having 1 x 8kw or 2 x 5kw inverters? But if I have the geysers converter to Solar, I believe the 8kw will be more than enough?

2.If you say it would max out at 8.8kw what happens if the grid is on and I would use more than the 8.8kw? From what I read and understood is that anything more than 8kw if grid is available will use passthrough and supplement anything over 8kw up until 90A = +-20kw total?

3.For the oversizing I believe that solar array only produces around 80% of the rated depending conditions etc. so that would get me closer to the 8kw the inverter can supply, on your 4,5kw of panels what average kwk would you get ?

4. The house also have 5 Ac units, if extra power is available after batteries are full, I would like to throw it at the ac units or geysers

5.I will have a look at the CBI Astute wifi timer for the geyser thax a lot, yes would like to have the geysers only come on during the time when the sun is up.

I still need to find alternative to the ovens not sure what’s available, my mom likes to bake :D

Do you also use the sunsync inverter on your setup and how much kw do you produce on average per day with your 4.5kw panels?

 

1. The 8kw inverter should be fine. I have a solar evacuated tube geyser and 3 aircons running from the inverter. 

2. Correct. It will pull what it needs from the grid. 

3. I get about 80% from my panels but in summer this increases to 90%. Currently have 8.54kwp of panels and adding another 1.83kwp on Sunday. 

4. This is possible using the aux as a smart load output. 

5. Can't comment here. 

My average pv production from 8.54kw of panels is 45kWh per day. 

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Thanks Achmat,

 

1.Okay thanks so the 8kw might do the job for what my needs are?

2.If you say it pulls what it needs from the grid can this be continuous say the load stay high for more that a hour or whatever the case might be or is this only for a certain period of time?

3.Great so the average should be around 80% this is on pitch roof correct, if you are adding more should they be the same watt on the panels?

4.So all non-essentials should go on the smart load or aux port

45kWh per day I believe is good, it is close to what I use now but without the Ac in the new home that should add a bit.

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32 minutes ago, Tariq said:

I have my 2 kW geyser connected to the Smart Load output, set the solar threshold to 2200 watts and battery to 100% ON and 95% OFF, works great, and there is cloud cover i switch on "Always On Grid "

That's also i great thnx, getting some quotes now for solar conversion just to help om the heating of the geysers.

 

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12 minutes ago, Frost said:

Thanks Achmat,

 

1.Okay thanks so the 8kw might do the job for what my needs are?

2.If you say it pulls what it needs from the grid can this be continuous say the load stay high for more that a hour or whatever the case might be or is this only for a certain period of time?

3.Great so the average should be around 80% this is on pitch roof correct, if you are adding more should they be the same watt on the panels?

4.So all non-essentials should go on the smart load or aux port

45kWh per day I believe is good, it is close to what I use now but without the Ac in the new home that should add a bit.

2. It can pull continuously as long as you need it to. No time limit. 

3. Yes in adding 6 more of the same panels. 

4. So the sunsynk has two out puts. The first one is ups load output. This is your essential loads. The second output is the aux and can be configured to run loads when there are excess solar available. You can also configure it to run from batteries so you can still power these loads during load shedding if you want. 

The grid input is also and output and your non essential loads could be before the inverter. The inverter can then send power back through the grid connection to these loads. When there is load shedding however, these loads before the inverter will never receive power from the inverter or batteries. 

Current total PV generation since the system went live. 

Screenshot_20210319-115732_SOLARMAN Smart.jpg

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I have had two installers now that argue with me that it is not possible to supplement form the grid if you go over the max of the inverter, they say it switches over to bypass mode completely and only use grid power.

They say It can do so for a few seconds for startup load but not for continuous use. Apparently  it’s not good for the inverter to run at close to the max for long periods of time.

 

Wow that power production is great ist 41kw average per day over 231 days, on complete cloudy and rainy days do you still produce power if so, how much of your daily average to you get?

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Tells you that a lot of installers don't know what they are talking about, just the other day I was doing 7.52 kW's on a 5 kW Sunsynk, the 5 kW was coming from the inverter and the balance of 2.52 kW was being supplemented by the grid, and it probably was an easy 30 plus minutes, till the geyser and tumble dryer shut off

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8 minutes ago, Frost said:

I have had two installers now that argue with me that it is not possible to supplement form the grid if you go over the max of the inverter, they say it switches over to bypass mode completely and only use grid power.

They say It can do so for a few seconds for startup load but not for continuous use. Apparently  it’s not good for the inverter to run at close to the max for long periods of time.

 

Wow that power production is great ist 41kw average per day over 231 days, on complete cloudy and rainy days do you still produce power if so, how much of your daily average to you get?

Every installer I've found know very little about the capabilities of the sunsynk. I decided to find a sparky and told him how I wanted the unit installed and basically project managed him during the install. It's a hybrid so it will blend from the grid even if you go over the 8kw of the inverter. I have witnessed this first hand with screenshots in another thread. 

It still produces pv on cloudy it rainy days but very little. The lowest I think was the about 12kwh. 

Current month daily PV generation for Somerset West, Cape Town. 

Screenshot_20210320-094039_SOLARMAN Smart.jpg

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Still looks great, do you use some eskom power during the days that power production is lower?
Say i do go for the 2 x 5kw inverters to future proof is there any disadvantages in a parallel hybrid system, do they still share the pv inlet and batteries ?

 

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On 2021/03/19 at 8:54 AM, Paul Greeff said:

However, the Inverter will keep Aux load on while the battery has sufficient charge, so I still suggest adding a timer.

Pardon my butting in, but what is this feature? Is it allowing you to specify that you will backup the non essential loads until a certain DOD is reached? Obviously within, in this case, the 8kw limit. 

Going on from this, does this mean you actually have 3 sets of loads? 

1) not backed up

2) backed up

3) conditionally backed up? 

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10 minutes ago, Bobster said:

Pardon my butting in, but what is this feature? Is it allowing you to specify that you will backup the non essential loads until a certain DOD is reached? Obviously within, in this case, the 8kw limit. 

Going on from this, does this mean you actually have 3 sets of loads? 

1) not backed up

2) backed up

3) conditionally backed up? 

Correct. 

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13 minutes ago, Bobster said:

Pardon my butting in, but what is this feature? Is it allowing you to specify that you will backup the non essential loads until a certain DOD is reached? Obviously within, in this case, the 8kw limit. 

Going on from this, does this mean you actually have 3 sets of loads? 

1) not backed up

2) backed up

3) conditionally backed up? 

Further to this. 

When setting the aux as an output, the screen will show additional options to specify. 

1. Battery off. This will be when the inverter will switch the aux output off. 

2. Battery on. This will be when the aux will be switched on as an output. Off setting must be lower than on setting and is the SOC percentage. 

3. Solar power. This is the max battery or solar power that will go to the aux loads. So if you have a 2kw geyser, you will set this to about 2 200w.

4. On grid always on. This can be ticked so the aux output is always on if the grid is available. 

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4 hours ago, Achmat said:

Further to this. 

When setting the aux as an output, the screen will show additional options to specify. 

1. Battery off. This will be when the inverter will switch the aux output off. 

2. Battery on. This will be when the aux will be switched on as an output. Off setting must be lower than on setting and is the SOC percentage. 

3. Solar power. This is the max battery or solar power that will go to the aux loads. So if you have a 2kw geyser, you will set this to about 2 200w.

4. On grid always on. This can be ticked so the aux output is always on if the grid is available. 

Thank you @Achmat. That's some nice flexibility 

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15 hours ago, 87 Dream said:

Out of Interest what is the warranty & back up support of the Sunsynk machines in SA?

My own experience has been reasonable (compared with other manufacturers). No warranty claim as yet though, and I don't know many that have claimed. Local support via Whatsapp is quite responsive, and the Sunsynk forum https://www.sunsynk.org/forum (which is relatively slow, albeit community based), There's also the ability to raise an official ticket at https://www.sunsynk.org/tech-help.

Edited by YellowTapemeasure
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  • 3 weeks later...
On 2021/03/20 at 10:45 PM, Vassen said:

The 5kw inverter can supply a lot more than 5kw as Tariq has mentioned. My max solar production has been around 35kw a day I think but recently GP weather has been not solar friendly. the only time the 5kw limit really comes in is when there is no  grid and you are running off batteries. 
 

I’ve got my second inverter, got as far as mounting it on the wall. Got the cable and additional breakers today so hoping to wire it on Monday, then request a software update so that they both match, and then configure it to parallel. 
 

They will both share the same battery. The pv is separate and you can install 2 strings per inverter. That’s the main reason for me going for a second unit. 
 

The only disadvantage is that it will require 2x standby currents which will probably be around 100w.

 

Will provide some feedback once I have it installed. 
 

 

@Vassenif i have 2 x 5kw inverters can i use the 2 aux ports one for smartloads and another for generator or wont this work?

 

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On 2021/04/08 at 3:10 PM, Vassen said:

I am not really sure. I’m almost complete with my second inverter. Just need some final wiring and then request a firmware update. 
 

I know that you can only have 1 generator but not sure if the other can be set as an output or if both need to match. Maybe a good idea to check with sunsynk support. 

Okay great thanks, i am leaning towards the two x 5kw installation my only concern war the high frequency noise that some users experienced. But seems that was sorted?
I see the passthrough on 2 x 5kw is 70A where one 8kw is 90A am i correct by saying this? Hopefully in the next two weeks mine wil be up and running. 

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13 minutes ago, Frost said:

I see the passthrough on 2 x 5kw is 70A where one 8kw is 90A am i correct by saying this?

I don't know, but [email protected]=app 19kW and [email protected]=app 15kW, either way, your EL/CB is probably only rated @63A, I guess, so why worry, else its time to upgrade to 3phase X 40A each and be done with it...

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1 hour ago, Frost said:

Okay great thanks, i am leaning towards the two x 5kw installation my only concern war the high frequency noise that some users experienced. But seems that was sorted?

a colleague has the 5 kW Sunsynk and has the high pitched noise issue, can even hear it iemanating from his clothing iron, has not figured it out yet, the family has sort of gotten used to it

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4 minutes ago, Vassen said:

I have a doubt about that 90A. I would not really want to test it. One would probably end up tripping / burning down stuff before getting to 90A. 
 

Even the 35A in the 5kw seems a bit suspect to me. My unit went into overload and I don’t think the essential loads were 7kw. This was on an overcast day with very little solar available and batteries were not discharging because of the time of use I had set up. 
 

On a clear day, I’ve seen it push the generation to 6.5kw. 5.5 from the built in mppt and another 1000w from the micro inverter on gen port. 

O okay so just a guideline then, if you generate more that 5.5 kw and your batteries are not full do the extra generation get wasted or does it still goes to the batteries?
Do you also have the problem with the high pitched noise form your 5kw sunsynk?

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