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Excellent vid again Gary!
Re the Sig DC charger :  No, you don't need a 12 kW inverter to use the 12.5 kW charger. Even on single phase supply, you could run the 25 kW charger with a 10 kW controller...
It all depends on the number of battery modules you go for, as when there is no solar present the charger draws from the batteries DC first, then the grid via the inverter.
If you went for the maximum of 5 battery modules (1 slot for the charger), that is 45 kWh, meaning a discharge rate of 22.5 kW. So in that example the 25 kW charger would only require 2.5 kW from the grid (via the inverter) to charge at its maximum. The 12.5 kW charger would only need 3 battery modules (27 kWh, 13.5 kW discharge) to ensure never needing to touch the grid. Of course, if you charge during daylight it will use solar first, batteries second, and then the grid, if needed at all.

And remember, whilst your DC charger is drawing power overnight and depleting your battery storage, the Sig will still charge up from the grid at the same time at cheap rates, using the inverter's remaining capacity. So the 10 kW inverter might be drawing 2.5 kW from the grid for DC charging, it will use the balance to charge the batteries.

A very helpful video. In my experience, the inverter you should go for is the absolute biggest inverter you can afford at the time.

Yes I do.

10kW 3~ inverter with the 25kW DC charger. 18kWp solar array, 18kWh battery (9+9). I only just got it, so no summer results yet. But the winter months get me about 250kWh/m.

Most of the time I charge the car between 02h00 and 06h30 at 10kW because prefer to solar charge the battery for home consumption. But in summer I imagine charging by day at up to 18kW(p) whenever I can. I don’t see myself charging at 25kW from the battery any time soon…

Oh yeah, and I use the V2X quite regularly. Although for now I don’t understand the logic all to well. I find it doesn’t work optimally yet. So I usually turn it off if I can’t keep my eye on it.

Excellent Video as ever Gary - always learning. Your channel should be default viewing for anyone considering Solar, Batteries, ASHP, EV combinations.

Thank you Gary. Just watched this video of yours as I am looking at going for solar. So it was very helpful for the learning curve ! I've got a good size workshop in the back garden and I'm hoping to cover a good part of that with Solar panels.

Thanks Gary, and of course my 5kW hybrid inverter allows my batteries max output of 3.5 kW to be in addition to my solar output when my solar array struggles on cloudy days up to the 5kW limit.

Excellent, Gary! You renewed my curiosity about DC charging. BTW, today my 18 kWp with 6+6 kW hybrids, generated 23 kWh. If only we had more sun.

We ended up with a mix of grid tie and non grid tie inverters in order to keep under the G99 limit and be able to charge about 44kWh of batteries within the 5 hour window we have. Getting a bit close to the limit at this point with the water heating included.

8:06 Tesla Powerwall 3 having only 3 MPPTs is a big problem that is rarely talked about. PW3 was suggested for my mother's 2 bed bungalow, but due to the PW3 having a low maximum voltage per MPPT we couldn't fill both of the roofs with panels. We went instead for 2x6kW inverters with 2 MPPTs each giving us 2 MPPTs per roof and 12kW of PV which we joined with 20kWh of "server rack" LFP batteries and it all cost less than a single PW3 installed.

Hi Gary, thanks for the channel. I have found it invaluable in helping me understand the key factors in optimising a solar/battery system. I am now booked in for installation of a 4.32kWp array with Sigenergy 6kW Inverter and 9kWh battery in mid-July!
I have noted that it is often recommended to undersize the Inverter with respect to the maximum array capacity. My background is in power electronics for Railway Traction systems, such as the 1MW Converters and Inverters on the UK Pendolino trains. One point that was always highlighted to me was that the thermal cycling of the Inverter has a significant effect on reliability. A rule of thumb (from 25 years ago!) was that a 10C reduction in thermal cycle extended the lifetime by a factor of 10. This may be less significant nowadays with improvements in the power electronics devices, but it is clear that a hybrid or string Inverter will be carrying the highest solar loads in the summer when ambient temperatures are also higher. This influenced my decision to select a 6kW Inverter, significantly larger than the maximum array capacity of 4.32kWp. It also has the benefit of allowing some margin to export battery energy at the same time as solar output to maximise the benefits of peak time export rates.
It is often mentioned that the disadvantage of oversizing the Inverter is a reduction in efficiency, particularly in poorer light conditions. I did an online search for solar inverter efficiency curves and was pleased to find data for the Sigen range.
https://pdf.tritec.info/pdf/produkte/Sigen_Inverter_Efficiency_vs_Output_Power_Curve_20240118_EN.pdf
I was surprised to see that this shows the optimum efficiency is attained at between 30% and 50% of the nominal Inverter power, with efficiency reducing slightly at higher outputs. In real world conditions I do not think these small efficiency changes would be noticeable, but it does suggest that oversizing the Inverter does not have a major impact on performance. It would also be likely to improve the long-term reliability of the Inverter.
Keep  up the good work!

Greetings from Down Under! One thing you might want to consider when sizing your inverter is how much power can it deliver during off grid/blackout. If you have a large PV array and a large battery storage you might want to consider a larger inverter with enough grunt in case you want to charge your EV or run your a/c in off grid mode or during blackout .

Another informative video, thankfully I already know everything  covered (via your channel and others).
Luckily  for me I have a victron hybrid system with separate mppts, needed as I have two separate array of panels on my main roof and another set on my flat garage roof.

An idea for the future would be an upto date video on the none mcs route to getting paid to feed back to the grid. It's a question that gets asked a lot in forums I'm part of.

Thanks once again Gary for a first class video. Here at Project C it has been evolution and as such I have 2 PV arrays each with an inverter. One array is connected to a Givenergy battery system.
Maybe one day soon I will do as you have done / doing and rationalise the system. Thanks for the useful information. A

Great to heat you are getting Sigen system - you won’t be disappointed. I have a 25KW TP and it’s great to ensure no grid draw even when charging 2 EVs full chat.
I’ll look out for any comments on DC charger. My complication is location of SigenStor vs car parking.

I have had more than one system installed and each is connected to east and west facing panels so I have three inverters, all of the correct size for the connected panels, so never suffer from clipping and should one of them fail (one did) the whole system was not down while it was replaced. No doubt more expensive than one inverter but each is better matched to their input.

Superb video and welcome to the Sigenergy team.  It really fills me with confidence that I chose the right solution (with your help) now you are doing the same. My next EV will be V2H and I think I will go for the 12kw DC charger as I simply don't need 25kw fast charging, but I do want to utilise the battery for home use and export before the duck curve changes the tariffs.
Had my first power cut a few weeks ago over Christmas and neighbours at the door asking why my house still looks like National Lampoons Christmas and the full estate was in darkness has prompted them to install also. The UPS was flawless! I didn't even notice!

To clarify, if you have an AC tied battery the inverter has to do a lot of extra work.  But with DC strings and Hybrid inverters, there is a DC-DC path from the solar to the battery charging portion of the inverter which bypasses the AC entirely.   The actual AC inverter is not used for that path, it is only used for running the home and export.    The DC from the solar splits into two paths... one path going to charge the battery, and the other path going into the AC inverter to run the house and/or export.

This means that for homes with hybrid inverters the units can actually handle a lot more solar than people think.  That's why something like a Flexboss18 can handle 18kW of solar but only has a 10kW inverter.   These sorts of inverters have separate path limitations.  In this example, the FB18 can charge the batteries at 10kW AND output 10kW of AC at the same time.   Well, 18kW of combined power, anyway.

So there is actually a lot more flexibility in hybrid inverter-battery systems.  What you usually care about the most is that the combined output is not forced to export excess solar or curtail solar off-peak.  Later in the evening, the battery-to-inverter path winds up being the least important because it can dole the battery power out all night at lower power levels if that's what it takes.

All of that said, I think in today's world the minimum size you want is a unit with a 10kW inverter, and when going hybrid also being able to charge the battery bank at 10kW (with a combined capability of well north of 10kW in solar without having to export)... that's what really does the job.

-Matt

The bigger always better. Hybrid inverter 10 kw

Hi Gary, yet another great video. Niki and I are considering adding an ASHP and an EV. Our EV mileage is likely to be modest, most of the time. The ASHP in winter will probably be the heaviest demand. Getting the most appropriate car charger is also important. Thanks again!