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Which inverter? Looking for some guidance.


PsyCLown
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Hey all!

 

So I am wanting to get a solar setup as my electricity usage is quite high and it is hard to justify paying Eskom a large portion of money each month when I could go solar and reduce my Eskom bill significantly and have power for the essentials during load shedding or power outages.

I would look at installing the solar system towards the end of the year, so I am now wanting to do some research and get a better understanding of how everything works, what are good brands and so forth.

 

I am looking at 8KW to 10KW for an inverter, the house is single phase so any 3 phase inverters are out of the question.

I would like an inverter which is hybrid I believe - so runs off the solar panels, will draw extra power from the Eskom grid if the solar panels are unable to provide sufficient power and then have a battery to keep the essentials running off the battery during power outages and when the sun is not shining.

 

From what I have read, a hybrid inverter will be able to do this and they typically have 2 "outputs" which we could refer to as "essentials" and "non essentials" and this is tied to the battery, anything on non essentials will not be powered by the batteries and anything on essentials will be powered by the batteries.

Both essentials and non essentials will get power from the solar panels and the inverter will take power from the Eskom grid if the panels are unable to provide sufficient power (or when the sun goes down, but Eskom is gracing us with power).

 

I have seen some people struggling with certain brands of inverters or there being issues and requiring fixes or tweaks, firmware updates etc. I do not want to struggle and have hassles, I would like the equipment to work as it should.

 

So with that being said, what are some makes / brands which would be good and worth looking into and would suit my requirements? I feel it makes sense to start with the inverter and then can look into the panels and batteries later on.

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The sunsynk 8kw inverter is a good choice. Most of the threads here about it is more questions on functionality than issues with the inverter as well as installers not being familiar of the inverters capabilities. 

Mine has been installed for 10 months now and only issues were around a software update. Since then it's been working flawlessly and generated 11.67MW. Saving me nearly R30k in the process. 

It works with most brands of lithium batteries. Has a number of configuration options including the ability to add a micro inverter, wind turbine or generator. It has 3 connections. 

Bidirectional grid connection where power can be sent back to non essential loads. 

The load connection is the main or essential connection 

The aux is a configurable input or output depending on how you want to use it. This could be used for a generator, micro inverter or wind turbine input or it could be configured as an output as a second non essential output. 

Of you decide on a sunsynk then go with an accredited sunsynk installer as every installer that's out there and only worked on axpert type inverters will not be able to advise you on all of its functions and capabilities. 

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I have noticed the Sunsynk inverters seem to be quite popular.

Is the Deye and Sunsynk the same inverter, just rebranded? They seem quite similar, both physically and from looking at the specs seem to be possibly the same inverter?

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30 minutes ago, PsyCLown said:

I have noticed the Sunsynk inverters seem to be quite popular.

Is the Deye and Sunsynk the same inverter, just rebranded? They seem quite similar, both physically and from looking at the specs seem to be possibly the same inverter?

Same, same, but different.

Identical innards, but Sunsynk apparently has a more westernised user interface.

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Ok thanks, so seems Sunsynk is the way to go then - more people using them, good support, better UI.

 

I see Sunsynk have a web based portal / app for monitoring, is there no phone app which can be used instead? Alternatively, I assume one could access the inverters web based interface remotely via internet, provided there is internet at home?

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2 minutes ago, PsyCLown said:

Ok thanks, so seems Sunsynk is the way to go then - more people using them, good support, better UI.

 

I see Sunsynk have a web based portal / app for monitoring, is there no phone app which can be used instead? Alternatively, I assume one could access the inverters web based interface remotely via internet, provided there is internet at home?

You need to make sure the unit comes with the WiFi dongle. It's sometimes sold separately. 

There is the Solarman app on the Google and apple store. 

Screenshot from the app 

Screenshot_20210527-172041_SOLARMAN Smart.jpg

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1 hour ago, PsyCLown said:

I have noticed the Sunsynk inverters seem to be quite popular.

Is the Deye and Sunsynk the same inverter, just rebranded? They seem quite similar, both physically and from looking at the specs seem to be possibly the same inverter?

I think they just found a gap in the market at the right time. When I was looking for an inverter I needed an 8kw hybrid and at the time, victron kit was just too expensive with no single solution and many add ons needed to get the same functionality of the sunsynk. 

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Just now, Achmat said:

I think they just found a gap in the market at the right time. When I was looking for an inverter I needed an 8kw hybrid and at the time, victron kit was just too expensive with no single solution and many add ons needed to get the same functionality of the sunsynk. 

Right product, right pricing, right time.

 

One last question for now, might seem silly but I have seen some people listing their Sunsynk inverter as 8.8KW and others as 8KW in their signatures.

Is it the same inverter and it is actually rated for 8.8KW or are these two different models?

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Posted (edited)
1 hour ago, PsyCLown said:

Right product, right pricing, right time.

 

One last question for now, might seem silly but I have seen some people listing their Sunsynk inverter as 8.8KW and others as 8KW in their signatures.

Is it the same inverter and it is actually rated for 8.8KW or are these two different models?

It's the same inverter. Some are listing the max AC power of 8.8kw and others use the rated AC power of 8kw.

I prefer to use the rated power. Screenshot of the manual. Last column is for the 8kw. 

Screenshot_20210528-111100_Acrobat for Samsung.jpg

Edited by Achmat
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On 2021/05/27 at 3:58 PM, PsyCLown said:

...

From what I have read, a hybrid inverter will be able to do this and they typically have 2 "outputs" which we could refer to as "essentials" and "non essentials" and this is tied to the battery, anything on non essentials will not be powered by the batteries and anything on essentials will be powered by the batteries.

Both essentials and non essentials will get power from the solar panels and the inverter will take power from the Eskom grid if the panels are unable to provide sufficient power (or when the sun goes down, but Eskom is gracing us with power).

...

Non-essentials will still be powered by the batteries except if the grid goes down then they will not be powered at all, I have my geysers, stove and pool-pump on the non essential side.

I have a 8kW Deye that has been running for about 6 months so far and has save me about 5.4MWh of electricity. It is very configurable and I can't think of anything that I would like it to do that it doesn't

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On 2021/05/28 at 8:52 PM, Zerc said:

Non-essentials will still be powered by the batteries except if the grid goes down then they will not be powered at all, I have my geysers, stove and pool-pump on the non essential side.

I have a 8kW Deye that has been running for about 6 months so far and has save me about 5.4MWh of electricity. It is very configurable and I can't think of anything that I would like it to do that it doesn't

I see, would one be able to set it so that the non essentials can only drain the battery to say 80% or 60% and then stop drawing from the batteries to save it for the essentials?

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1 hour ago, PsyCLown said:

I see, would one be able to set it so that the non essentials can only drain the battery to say 80% or 60% and then stop drawing from the batteries to save it for the essentials?

Not possible but can be done if you put the non essential loads on the aux output. 

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Hmm ok, will likely need to speak to the installer then and see how best to set it up.

 

Unless you guys can advise. Basically there will be a few items which draw a lot of power running continuously, aircons being one of them.

If there is load shedding I am happy for electronics to not get any power. I would like the solar panels to power them during the day when the sun is out, to help reduce my monthly Eskom bill.

When the sun goes down, I was thinking they could be run off Eskom's grid as to run them all off a battery will require quite a large battery pack to last throughout the night until the sun is up again.

 

Any ideas as to what may be the best way to have it setup? I am happy for these electronics to draw people from Eskom when the panels are not working - or to drain from the battery until the batteries are drained to a certain percentage and then to take from Eskom's grid.
 

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1 minute ago, nightcrawlernic said:

Can i suggest you go with 2 x 5KW Sunsynk inverters. Instead of 2 mppt, you'll get 4. They come in handy if you have a complicated roof like mine. 

My roof is a flat concrete roof, so I think I have the luxury of being able to point the panels in any direction and at any pitch.

Would it still be worth while getting 2x 5KW inverters in such a situation?

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I agree. If you can afford it run 2x 5kw inverters 4x 5,2kw batteries from Lithium batteries SA. You can add 6000w panels per inverter giving you 12kw of solar. if you use the 8kw unit you can only use 8.8kw solar. 

The benefit is also that you have redundancy should an inverter fail.

a Setup like this will be costly but you will surely love the fact that you don't have a wife that complains when she cant watch her tv series. 

1. Sunsynk 5k R19000 x2 = R38400

2. Batteries R25k x4 R100k

4. solar panels 405w (11A max per string. 8 panels per string in series) x 32 R2300 each  R73600

R212k without all the other spares and installation but you will be 95% grid free. The reason why i say 95% is you might have that odd situation where you will have cloud for 2 weeks and the batteries will need a top-up from EKSDOM

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3 minutes ago, Krokkedil said:

I agree. If you can afford it run 2x 5kw inverters 4x 5,2kw batteries from Lithium batteries SA. You can add 6000w panels per inverter giving you 12kw of solar. if you use the 8kw unit you can only use 8.8kw solar. 

The benefit is also that you have redundancy should an inverter fail.

a Setup like this will be costly but you will surely love the fact that you don't have a wife that complains when she cant watch her tv series. 

1. Sunsynk 5k R19000 x2 = R38400

2. Batteries R25k x4 R100k

4. solar panels 405w (11A max per string. 8 panels per string in series) x 32 R2300 each  R73600

R212k without all the other spares and installation but you will be 95% grid free. The reason why i say 95% is you might have that odd situation where you will have cloud for 2 weeks and the batteries will need a top-up from EKSDOM

Max solar on the 8kw is 10.5kw so would be interesting to see what the inverter does with this excess. I increased my panels to 10.3kw but only in the last month so will only really see this impact in summer. 

Interesting how solar and batteries has dropped in the past 6 months. A year ago that setup would've cost a bit over R250k. My own system set me back R230k 8 months ago whereas if I installed it today it would only cost about ±R180k

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2 hours ago, Krokkedil said:

I agree. If you can afford it run 2x 5kw inverters 4x 5,2kw batteries from Lithium batteries SA. You can add 6000w panels per inverter giving you 12kw of solar. if you use the 8kw unit you can only use 8.8kw solar. 

The benefit is also that you have redundancy should an inverter fail.

a Setup like this will be costly but you will surely love the fact that you don't have a wife that complains when she cant watch her tv series. 

1. Sunsynk 5k R19000 x2 = R38400

2. Batteries R25k x4 R100k

4. solar panels 405w (11A max per string. 8 panels per string in series) x 32 R2300 each  R73600

R212k without all the other spares and installation but you will be 95% grid free. The reason why i say 95% is you might have that odd situation where you will have cloud for 2 weeks and the batteries will need a top-up from EKSDOM

@Krokkedil are you advertising these prices? You can PM me if you are selling.

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4 hours ago, Krokkedil said:

I agree. If you can afford it run 2x 5kw inverters 4x 5,2kw batteries from Lithium batteries SA. You can add 6000w panels per inverter giving you 12kw of solar. if you use the 8kw unit you can only use 8.8kw solar. 

The benefit is also that you have redundancy should an inverter fail.

a Setup like this will be costly but you will surely love the fact that you don't have a wife that complains when she cant watch her tv series. 

1. Sunsynk 5k R19000 x2 = R38400

2. Batteries R25k x4 R100k

4. solar panels 405w (11A max per string. 8 panels per string in series) x 32 R2300 each  R73600

R212k without all the other spares and installation but you will be 95% grid free. The reason why i say 95% is you might have that odd situation where you will have cloud for 2 weeks and the batteries will need a top-up from EKSDOM

Yeah, a little pricier - although how does the setup work with 2x inverters?

Do the inverters link to each other and the rest of the setup remains pretty much the same? Like the circuit breakers wont be split between the inverters and I could get a single battery pack and just connect it to one of the inverters?

 

One thing I have absolutely no clue about is installation costs and the cost for a mount / bracket - especially considering I have a flat roof.

 

Also what happens if there is excess power from the panels? Like say a 5KW niverter which can handle say 6KW of power. However you have panels capable of producing 8KW and on a sunny day you end up having them generate more than 6KW, what happens to the extra power? Is it a problem for the inverter? Does it just not get used?

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The 2 inverters gets connected in Parallel. it is always a good idea to have separate circuit breakers for them. they connect using a parallel cable the one will be selected as master and the second as slave and the master control everything. 

The Batteries also get connected in parallel. Each inverter should have a fuse on the battery wiring again to isolate the battery from each inverter separately.

When you install bigger solar powers than what the inverter can handle the MPPT will have issues. The extra power needs to be throttled back by the MPPT when it is not in use. If you have the ability to export to the grid you can but never more than what the MPPT can handle. It is never a wise idea to install 8kw on a 6kw MPPT the electronics will not be able to handle that. 

Usually the Solar panels and cables has a 15% efficiency loss. this can be made up by adding to the string but you must always ensure that you stay within the max Open circuit voltage and Max Amps the MPPT can handle. 

The MPPT on the inverter can handle 6000w at max 500v and max 11A. If you use a JA solar 540w panel with the VOC of 49.9v and the max amp of 13A you are over the Amperage specification. but if you use the JA solar 465w panel you have a a VOC of 50.1V and a max 10.96A. But because the system can handle 6kw 6000/465=12.9 or 13.

13 divided/ 2 gives you an unbalanced string, therefore you must either run 2x6 or 2x7 465x14=6510w

The voltage will be 7 x 42.43(VMP)=297V at 11A you must always ensure that the maximum Open circuit voltage is lower than what the inverter can handle, The VMP is the maximum voltage when the panels are under load. The IMP is the maximum Current when the panels are under load.

It becomes very technical but if you have shading you will not run at maximum and more panels can be added but must be done carefully, the same apply for cable losses and panel inefficiencies. 

Personally I would never add more than 10% above what the MPPT wattage is specified for. In this inverter 6600w.

 

Installation is an area where there is a lot of things that must be considered. Type of roof, height of roof direction of roof, roof area, Roof construction inside(will it handle the extra weight).

2nd DB construction, is it easy accessible where will the inverter and battery sit, does the db need a replacement of all the circuit breakers is the house wiring up to code or does it still have old paper wiring. what will be powered. Earth testing to determine if new earthing needs to be done.

I don't want to scare you, I want to educate you. Most of the work can be done DIY if you know how to use tools. If you don't know the basics of electricity learn that first

The reason Why installation costs is so expensive is because there are a lot of unknowns and the installer needs to carry the guarantee if anything goes belly up.

I started small with a 3kw inverter 4 batteries and 2 solar panels. I do have electronics and electrical background and installed it myself. I now have 12 panels and a 5kw inverter and a big Lithium battery. 

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On 2021/05/27 at 5:38 PM, Achmat said:

The sunsynk 8kw inverter is a good choice.

This one sounds like a good option. Wish it was available when I installed.

Could keep everything on the essential side and just maintain the max load to below 8kW. Think my max is in any case below 7kW

And this should be able to blend battery, PV, and Grid ???

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