Giv-Gateway without All in One?

Hi All, delved into the forum as I can't quite work this one out myself from the information available online (that I actually understand at least...).

Looking into Solar PV + Battery Storage (from a blank slate). The GivEnergy products look good, warranty good, Octopus Agile compatible and a British company (what isn't there to like).

A friend made me aware of the All in One + Gateway bundle. Seeing that the bundle can keep you going even if the grid fails was an interesting proposition, but I notice the All in One is AC coupled and reads as if additional inverter required anyway for the PV installation.

Just wondering what the best setup from the available GivEnergy products would be to handle a 7.65 kWp (18 x 425W) array to supply a single phase house with battery storage (in the region ₁₅ kWh)? Ideally it would be amazing to have the ability to keep the house going in the event of a power cut, especially as I'm also considering a ASHP at the same time!

Thanks in advance

Declan gateway cannot be sold without the all in one and currently only works with that.

Declan there's pro's and con's of AC or DC coupled

If you don't have PV already then a hybrid inverter & batteries is cheaper but even the latest gen 3 hybrid is limited to 3.6kW draw on a single inverter https://givenergy.co.uk/wp-content/uploads/Datasheet-Hybrid-Gen-3-3.6-Mar-2023.pdf
These can provide an emergency power supply capability, whole house if you want or just a few key circuits. You don't need the gateway, the inverter will do this for you out of the box, but it's limited to 3.6kW draw so you might have to turn off the oven and heat pump for example.

Multiple hybrid inverters with their own batteries are also possible although this is not a recommended configuration, I have it and it works. You can increase the emergency power supply çapacity by how the circuits are spread over the inverters. An 8kW pv array would indicate two inverters anyway.

The strength of all in one is it's high power draw capabilities and whole house EPS. It's aimed firmly at Tesla power wall and has better specifications

Declan Honestly with those panels id recommend the AIO+Gateway just for the fact that on the days where sun keeps hiding behind clouds that array could fill your batteries up nice and quick in just a couple of hours of sunlight since you will cap out the 6kw input it is capable of instead of being capped at 3 or even 3.6 charging speed and then when clouds come again you can just float off of the daylight.

There are other options for high voltage batteries but Solax are limited to 1 master and iirc 2 slaves so 3x5kw batteries max per inverter.

Thanks, so would microinverters, all in one and gateway be a sensible setup?

I read somewhere that the reason GivEnergy state full discharge is that actually the batteries are larger than quoted (i.e. the all in one is really more like a 15kW setup you'd get from anyone else)?

Declan The batteries are over-sized yes so when you get a 100% depth of discharge quoted, its 100% of the usable capacity. There is more held in reserve at the top and bottom end that you never see.

Take a look at the “Gary does solar” videos on YouTube, he looks at micro inverters and power optimisers, the benefits and impacts, etc.

But in short, yes micro inverters, an all in one and a gateway is a sensible setup.

Thanks, I was previously angling towards optimisers (as appeared to be more cost effective and couldn't quite square off that the highest capacity in the iq7 range appears to be 366 - so surely adding a bottleneck!?).
I've enjoyed the Gary does solar videos I've watched so far but think I've caught them in a very random order (so may need to double back)

A quick Google does suggest that other brands offer 6, 7 or 8 kW inverters, so I guess a 3rd party inverter could be paired into this (not sure what issues that might add though?)

Are there any particular challenges to navigate with running 2 parallel sets of hybrid inverters and batteries as you said you do in your previous reply? Is it easy enough to control what's happening? How did you end up/decide on that approach?

Declan Yes, do go back and look at the Gary videos. He doesn’t recommend power optimisers because (a) failure rates of them are relatively high, and (b) individual panels do a pretty good job of optimising power themselves. It all depends of course on your roof, how shaded it is, with trees, poles, buildings, etc.
If you have micro inverters then each panel has its own inverter so you’re getting much of the benefits of power optimisers anyway. I think in his video he says that if he was putting in a new system now he would put in power optimisers.

If you’re going down that route, any 3rd party inverter can be paired with the all-in-one, it doesn’t care, its just dealing with the AC power, regardless of how it was produced. One disadvantage of AC coupled inverters is that by their nature they will incur more power loss as you’re doing more power conversions than a DC coupled hybrid inverter. Maybe 5-10% more loss as you convert DC from panels to AC in the inverter, then back to DC in the all in one battery and back to AC when you discharge the battery and use it. A hybrid inverter will have less conversions with DC stored straight away in the battery and only converted once when you discharge the battery to use it.

r/e issues with parallel hybrid inverters. GivEnergy say that this is not a recommended configuration as the two inverters are independent of each other and don’t know of the others existence so operate independently. There is an Energy Management System (EMS) that couples the systems together that’s in development/test, but that’s been coming for a while so I’m personally not waiting for it.
My system was designed with two inverters because of the size of my 10.4kW array would exceed a single inverter. What I didn’t realise until some time after installation was that this wasn’t a recommended configuration and the inverters (and their batteries) would operate independently.

I have heard issues of one battery discharging to fill the other one up, and strange data reporting in the portal, but frankly I have never had those problems (although the portal data is messed up for me anyway as I also have an older 4kW FIT array that the GivEnergy system knows nothing about). For me the multiple inverters has worked flawlessly. I have a battery on each inverter (9.5 on one, 5.2 on the other), they both charge up separately, and when there’s house demand they both respond, ramping up discharge to meet that load. Then when the load is turned off, they both ramp down to whatever the new load level is. I have seen a couple of advantages of this approach as well, with 2x hybrid inverters I get double the discharge rate when force exporting to the grid or to meet house demand. I’ve got gen 1 inverters which are limited to 2.6kW, but with 2 inverters I can charge or discharge at up to 5.2kW.
Also as the sun moves round from front of the house to back the inverters can be doing different things. The one on the front of the house can be discharging to meet house demand whilst the one on the back is still charging up the batteries from the late afternoon solar.

Worth saying you do have to have a battery on each inverter (in my experience). Early on I only had the single 5.2 battery whilst I was waiting for the DNO approval for the second battery. Then when that came the installers fitted it to the same inverter that the 5.2 was connected. This meant 1 inverter with two batteries and one with no batteries. So all the solar that the second inverter generated had to either go to the house or the grid. I got quite a lot of grid over-voltage errors from this setup, causing the first inverter (with the batteries) to switch itself off for hours on end. Once the batteries were moved so there was one on each inverter the problem went away and its been great since.

It is possible to have multiple AC coupled batteries but I have heard that other people have more problems with this setup, and for them the EMS is probably more needed. Note that at the moment you can only have a single all-in-one, probably for the same reason, the literature says “up to 5 all-in-one’s” but “(coming soon)”.

Declan just a warning, Gary does solar conclusions on optimisers are based on inverters that support shade mapping, or global mppt. I was confident I didn't need optimisers, as was my installer. However givenergy inverters do not support global mppt, so I should have got them . There another thread on this, if you look for global mppt. If you have shade, and are choosing an inverter that supports global mppt, then the Gary conclusions are sensible.

justpassing
Thanks for the heads up a useful distinction - as with any new area looking into so many key terms or acronyms to watch out for on datasheets etc. A useful one to be on the look out for

geoffreycoan
Managed to watch a few of the video's earlier (still more to go). I've been sent into a bit of a "what if part of it breaks" spiral if I'm honest ...

Does sound like some optimiser brands have poor longevity, there are costs to actually install replacements, assuming the same or compatible units still on sale (no guarantee if 10-30 years down the line).

The other system that I'm considering (as suggested by a local installer) is a Huawei 6kW hybrid inverter with 15kWh of Luna batteries + Huawei optimisers. Failure rate of these optimisers seems low compared to other brands. However, looks like they are only compatible within the Huawei product line. Cost of the kit appears comparable to GivEnergy, my charge/discharge rate would be lower than the AIO, but it would be DC coupled so where charging from solar I'd have fewer losses.

I think I will need some form of additional shade protection over and above the bypass diodes as for a good chunk of the year I will get varying shade levels over a portion of the array due to a near by tree, and it sounds like "excessive shading" is a caveat used by a number of panel manufacturer's wrt to warranty validity.

A nice plus point to the microinverters is that should you require replacement panels (or have panels at varying degradation rates) then everything is running as best it can. Also (presumably) it doesn't matter in the future if the original spec microinverter is unavailable as the output is all AC.

The disadvantage is being forced onto AC coupled batteries. However, (outside of any agile tariff games) I'm likely to be filling any given battery from AC over the winter months anyway to ensure that I'm consuming the cheapest electricity, and in the summer targeting as much self consumption as possible. So I think I can likely square off this disadvantage (but would want to look for charge efficiency / loss stats for the battery of choice).

The advantage in my eyes of AC coupled batteries is that you're not wedded in anyway to the architecture of your solar array, or if issues with the array the batteries can still be grid charged (i.e. the hybrid inverter is a massive potential single point of failure for the other setup I'm looking at). Also feels like it gives the most future flexibility for system extension etc, again independent of your array architecture.

So on the microinverters + AIO + gateway option the question really becomes is it worth waiting for the IQ8 to land in the UK (as it looks like some additional capacity gains) or stick with the known reliability of the IQ7 range?