Christoff83

Your home's DB should be wired to protect itself and circuits connected to it. That is true whether you wire in a generator, inverter, appliance or whatever. For small loads a relay will work fine. 

The other downsideI when using a relay you won't have seamless power transfer but if you use the correct ATS you could have transfer without interruption of supply to your appliances.

Hi Christoff. An 8 pin relay will just have enough contacts for the 230V connections. This means your inverter has to be on the whole time. The 11 pin relay in my drawing allows for using the remote on/off function that my inverter had. This will save on the no-load losses of your inverter.

No offense to Christoff83 but adding a relay to that circuit may be the least of the not allowed worries. Mechanical interlocking contactors were probably best practice 50 years ago. Put a PLC on it and monitor each phase. Then you can protect, delay or even sync as you wish.

Personally I am only worried about safe operation and feel you should put focus on earthing. In terms of complying to regulations you would have to decide if this is an appliance, fixed installation, UPS, SSEG or whatever. This will introduce different requirements.

Morning, thank you for picking that up - I am aware it is in manual though - the problem I described definitely occurs while in Auto.   It is currently in manual as that is the only way for me to test the setup at the moment.

The ATS has a coil and caps. I think these cause inrush currents that the inverter can't provide. The pamphlet mentions that the unit can spontaneously ignite if you don't provide sufficient voltage... good luck.

@Christoff83https://www.power-sonic.com/blog/what-is-a-battery-c-rating/#:~:text=The battery C Rating is,10 Amps for one hour.

Wiring seems to be correct. What battery type is the 12v 100ah is it lead acid or lfp?How are you going to charge the battery beside the solar panel? You need to change the breaker and fuse on the solar side you can use fuse or breaker but max 20A 10A preferable as the fuse (80A) and breaker(63A) won't give any protection as you won't exceed 4 amp from your solar panel output when using PWM. Fuse and breaker on Dc battery side is ok @ 700w you will draw 65amps from the battery. On the Ac input from grid use 5 amp curcuit breaker. Still don't know why ats won't switch over as the wiring seems to be in order.

If you can work on an ATS, you can work on a relay. See my proposed wiring diagram.

Will do...
Little bit scared to have that open for scrutiny..  but fair enough I guess.

Morning,
 
Charging happens with an old 240W solar panel and PWM charge controller I had lying around.  Well, not lying around, the panel and PWM use to serve a similar purpose in my own house until I installed full solar a few weeks ago so I'm trying to put together a lights backup for someone else.  Seems to work well except for the ATS not switching in all directions.
 
Thanks

Small difference, using the example of Sunsynk/Deye: Your essential loads are limited to the passthrough current of say 35A for the 5kW, and 50A for the 8kW, but the whole household including the non-essential loads can draw up to 80A or whatever your main circuit breaker is rated at, and the inverter capacity can also feed surplus to the non-essentials.
I have a 5kW for cost containment. A greater passthrough would have been useful on occasion but you learn to adjust.

Hi all,
As with many previous threads around this topic on this forum, and other forums, I’m wondering whether to install 5kw or 8kw inverter.  Having read quite a few threads and articles, I want to try summarize my view on it.
 
For me, the top key takeaways from these discussions are:
Understanding the difference between inverting capacity and passthrough capacity.  When an inverter is advertised as 5kw, typically that refers to its continuous “inverting capability” meaning – to me – that while eskom power is off, you cannot carry more than 5kw load; or even while power (eskom) is on, you cannot contribute more than 5kw from your solar array or battery. BUT, a 5kw inverter does not mean that you are overall limited to run your house at a maximum of 5 kw all the time.  I see many manufacturers refer to a continuous AC pass-through power or current. Today I’ve seen a few as 50A which – again, to me – means 230v AC @ 50A means around 11.5kw load you can carry in your house WHERE a theoretical maximum of 5kw could come from your solar array or battery. Most high-quality inverters are informally known as “true hybrid inverters” which means in the above scenario, your house can run up to a total of 11.5 kw where the first 5kw will come from your inverting capacity (solar or battery) and the shortfall from 5 to 11.5 will be “blended” from eskom. This of course assumes eskom is on and that you also have 5kw available from your solar array or battery. While living with higher self-consumption, some people prefer to parallel two 5kw’s instead of going for a single 8kw because: Lower entry cost (you can start with one 5kw and add another later) Redundancy.  If an inverter fails, chances are you’ll have another while repairing… More MPPT’s with added capacity and flexibility (depending on the brand). Lower noise levels on the 5kw potentially. Have wheels, will travel.   When estimating usage, one can probably add 20-30% on your current usage as one would be inclined to use electricity more freely when it becomes free off sun power.  
So two questions for the audience:
Would you agree / disagree with my key takeaways above? In light of the above, assuming it’s more or less correct, is there anyone who implemented a 5kw inverter who wished they had gone for 8 kw or anyone who had gone for a 8kw and realized that a 5kw would have been sufficient?  
Any other comments welcome.
Cheers

This is correct. How much passthrough depends on the inverter and not all of them can do it. Assuming you are talking about the sunsynk and deye derivatives, then yes.
This is quite a nice reason to go for the 2x5kw but do remember that the 8kw sunsynk does have higher current ratings on the MPPTs so you can use larger panels without clipping.
In the end I went for the 8kw as it works out cheaper upfront and is a single install rather than having to pay for two installs at different times. 8kw is more than enough for most households and the batteries tend to be more of an issue at the end of the day anyway. For me, the only benefit of the 2x5kw setup is redundancy and that might be a major driving factor for some - even if more expensive overall.
One thing to note is that the 8kw sunsynk/deye has quite loud fans which come on every so often. This is not an issue if you install inside a garage but if installed in earshot, it is irritating. AFAIK the 5kw (and therefore 2x5kw) synsunk/deye inverters do not have this "issue".
Edit: I must add, if you have a few aircons and a pool pump - we have an old school aircon that draws 3kw when running - then the 5kw one is likely not enough. With that said, I have a friend who put his whole house on a 5kw system and has had no issues.

The negatives with 2 X 5kW vs 1 X 8kW is that I'm pretty certain the self consumption of the 2 are higher than for the one, so energy wasted, which, if you are sailing close the power limits of the battery bank used, could be a real big issue...
I was looking at the 8kW Sunsynk in 2020, but could not stretch the finances and ended up with the 5kW Sunken Synk, well, we haven't had any issues, we're mostly off the grid, but have an extension lead to the neighbour rated at 10A/2k2W, so in case of cases, assuming Eksdom hasn't left the building, like they did yesterday, just 20minutes after our 4hour rolling blackout, only to come back at around 1600 today, we can draw some from the neighbours extension lead, but never had to, for actual load, this end, so 5kW is probably close to our peak consumption...  (actually had a few spikes around the 7kW mark, with Eksdom awol and me cutting the lawn with my trusty '80s vintage Wolf 2000, 1k8W rated, but startup current on inductive load... 'nuff said.)
Either way, you'd need to look at your usage graphed out minute by minute over a week or two, to see what you need in terms of inverter size. Here we may need to consider adding in the future, certainly solar panels, since an air conditioner/cooler or two are probably on the horizon for us, these will be used during the day to keep the house cooler and those electrons will have to come from somewhere, the extension lead will no be around in the future either...

Thanks for all the info.
 
Lately I think these vehicles make more and more sense for my household...  or households such as mine.
Consider this:
We have two vehicles.  Both ice. Thanks to covid changing the world, both the wife and I work from home now.  Zero daily commute to work. We are lucky enough to have the school in our neighborhood, literally 300m from our house.   The SPAR is 500m. A good estimate would be that 90% of our driving is school run and shops - everything so close. I don't think - for daily commute type stuff - we do more than one or two short trips per day.  
Unless I'm missing some critical detail, it would make sense for us to change one of two vehicles for full electric (not hybrid).
For holidays, weekend trips or any other occasional longer driving, there is still one proper diesel powered SUV.
What I don't know is life expectancy of batteries and costs related to that.  This could become a deep rabbit hole.
Thanks again for the info!

Thanks for all the info.
 
Lately I think these vehicles make more and more sense for my household...  or households such as mine.
Consider this:
We have two vehicles.  Both ice. Thanks to covid changing the world, both the wife and I work from home now.  Zero daily commute to work. We are lucky enough to have the school in our neighborhood, literally 300m from our house.   The SPAR is 500m. A good estimate would be that 90% of our driving is school run and shops - everything so close. I don't think - for daily commute type stuff - we do more than one or two short trips per day.  
Unless I'm missing some critical detail, it would make sense for us to change one of two vehicles for full electric (not hybrid).
For holidays, weekend trips or any other occasional longer driving, there is still one proper diesel powered SUV.
What I don't know is life expectancy of batteries and costs related to that.  This could become a deep rabbit hole.
Thanks again for the info!