10.66kW Array

I have a customer who is looking to install 10.66kW array with approx 20kWh of batteries.

What is the best solution to do this?

Any help is appreciated.

For me, it would be two Gen3 hybrid 5kW inverters with a 9.5kWh battery on each. It's not a recommended setup, but is supported and a number of end users have it ( including myself).
It's not without its quirks, but can be controlled better by HA and wil be supported better in the future with EMS (Energy Management System).

94jdh Wallselec I have a very similar setup, 10.4 solar pv and 14kW of batteries.

I have two gen 1 hybrid 5kW inverters, a 9.5 and a 5.2 battery, one on each inverter. I'd buy gen 3 now for the higher charge and discharge rates

As said its not a recommended configuration but it works fine for me

Thanks for your replies, would both inverters be standalone or can you parallel them? Would a gateway be beneficial at all?

In all honesty I would avoid using multiple inverters in an GE installation at the moment. They still don't play well together and the solution has been "coming soon" for quite a while (this was originally called "Plant Mode" but is no longer supported).

Also they would limit the household to 3.6kW per inverter when running on battery only (Max. Charge / Discharge Power 3300W / 3600W)

You will have to speak to GE and see if the the AIO can be run in parallel at the moment, its "another coming soon feature".

The AIO are in effect AC Coupled Batteries but the included Gateway is brand agnostic when considering inverters. They also have 13.5kW batteries and a continuous power supply of 6kW (6000W nominal AC output power
7.2kW @ 10s, 6.5kW @ 30s peak power)

You are likely going to have to run into limitations on String size either on total voltage (Series) or current (Parallel). If you chose the right panels you could probably get away with setting this up in 4 strings with 2 of each paralleled and that would fit within your inverter mppt limitations.

You could go the route of Solar Edge which have their own micro inverters and this simplifies things but I have never really been a fan of micro inverters (or optimisers) as if they fail then the installer (or consumer) has to incur the cost of scaffolding to replace them. Solar Edge have a fairly well established failure rate of about 10% over a 10 year period.

Personally I would go for 2 x SunSynk 5.5kW (or 8.8kw) Hybrid inverters paired to 2 x AIO's (assuming they will run in parallel). The 5.5kW meet your pv requirements and would work well with the AIO's.

If you decide against the AIO's then the 8.8kW give you more leeway on powering the property when running on Batteries only. This is often missed when designing a system where the consumer wants to be off grid (or load shifted) as much as is possible.

This gives you good quality inverters and 26kW of battery storage at a really decent price.

Be warned though there are still some teething issues with AIO's it would seem looking at the threads in this forum plus you will 100% need to double check that the AIO's will play nice together.....

Sunsynk also recently announced the 5.5kw AIO. Its a 5.5kW Solar Inverter paired with 5.2kW battery (90% DoD I think) so 4 of those may be an alternative - but they literally announced them a few days ago and no idea if they are available or @ what price.
https://www.youtube.com/watch?v=u6Cqq1iGI_M

dragon2905

The plant system is supported, just not recommended - it's still available through the commissioning portal.
The EMS is currently going through a hardware beta, and a software cloud version on beta. That and the the large following and files set up to download on GivTCP for HA gives you plenty of options.

94jdh As I said, my hybrid plant setup works fine, the two inverters operate independently of each other and both ramp up and down to meet house load. I get double the discharge rate of a single inverter as well

geoffreycoan

My original gen1 inverters worked fine independently as well - it was only the change to Gen2 then Gen3's that introduced cross charging - apparently this was due to them monitoring AC which originally wasn't done by the Gen1's.
That said, it still can be resolved by the method I've mentioned above.

94jdh interesting to know about the later generation hybrids.
I'm on gen 1's.

I have thought about upgrading to later gen inverters but the cost of two new inverters wouldn't outweigh the slightly better charge and discharge rates. How did you do it, did you get a trade in on the old inverter?

Thanks for all the replies, I am even more confused now! 🙂
Customer is adamant on Givenergy but I don't think they have the set up for larger arrays.

geoffreycoan As a consumer you are happy to take the chance that it does, or doesn't work

As an Installer you just want it to work, no call back, no problems. Every time you have to respond to something not working costs you money (or east into your profit).

Wallselec with the size of the array it seems to be a fairly large property, are they on single phase or 3 phase supply?

You need to establish the following parameters for electricity use: Annual and Daily (you could also try and separate this by seasons but that's a bit harder to do unless they have actual data).

Adjust these numbers as you see fit but to get an approximation "ball park number" I would use something like divide by 14.2 (the sum of the each monthly number) and multiply by the following:
Jan 1.4, Feb 1.4, Mar 1.2, Apr 1, May 1, June 1, July 1, Aug 1, Sept 1.2, Oct 1.2, Nov 1.4, Dec 1.4.

Hopefully they have an In Home Display. From this you should be able to a baseline of background energy use - turn off everything that you reasonably can. Then go round and turn on the lights in the major rooms that would be occupied during a winter evening and the devices (tvs, computers, laptops, gamin boxes etc, PLUS oven, electric hob, kettle any other cooking appliances). If they have a Heat Pump or use electric for their heating/hot water needs remember to include this in the figures. This will give you a peak electricity demand level.

Contact GE and get it in writing whether they would recommend installing multiple hybrid inverters in one installation and then show this to the customer.

I would also do the same regarding the 2 x AIO's - get it in writing whether it is supported or not.

Depending on the above I would explain the situation to the customer that IF you install 2 GE Inverters then there is a, good, chance that they will experience issues and that you would not be comfortable with this (or prepared to accept responsibility..... that's your call).

I would emphasize the downsides also.

Each inverter can only supply 3.3kW to the house load when running on batteries only - when there is no solar. So if their load is higher than this then they will be drawing energy from the grid regardless of the size of battery storage that they have.

The reason I mention SunSynk is that they have been in the business for 20+years offer excellent products at good prices and offer great support to installers.

You could offer My Energi Libbi instead - 2 x 5kW inverters + batteries. But they are going to cost 30% more (+/- I would think). But you would need to check that they can be run in parallel together.

When running on Battery only they are slightly better than GE in that they will run 5kW discharge (not 3.6kW)
https://midsummerwholesale.co.uk/pdfs/libbi-datasheet-rev-2-18-october-2022.pdf

geoffreycoan

My contract was for two Gen2's and they weren't available so the Gen1's were fitted and then the correct ones installed once available.
The reason for going Gen3's was because the company failed to extend the warranty within 60 days, that and other problems then going bust meant a section 75 claim.
An inspection report and two quotes later to rectify, but the card company responded quickly as did the new installers.

94jdh ah, thanks for explaining. At least you managed to get to the latest inverters without additional cost to you. Albeit with what sounds like a load of hassle.

My contract only specified 2x 5kW hybrid inverters, no model number. It was only afterwards did I discover I was on the "old" stock, probably the installer wanting to shift it as the gen 2 was available at the time.
I was fully aware that I was getting two inverters due to the size of my array and that was what the installer designed. Again only afterwards did I learn givenergy do recognise but don't recommend this plant solution.

Wallselec have a look at this article with replies from givenergy about multiple inverter setups

https://community.givenergy.cloud/d/703-dual-inverter/

Wallselec I'm updating mine from around 7.5kW PV to approx 14.5kW.

geoffreycoan

I'm hopefully going to get some time this week to set up HA - I've been threatening it for a while!