Hi my question is can I run 2 + separate 5 KW Hybrid inverters with separate batteries with 2 gem20 CT’s on a split load DB with the CT’s on the incoming live tail of each RCD
This is all Gen1 system
Yes you can, its not dissimilar to my own plant arrangement with two Gen 1 hybrids each with their own battery.
A couple of points though:
There’s no real benefit in wiring the inverters up to separate distribution boards, you could just as easily wire them up with both inverters connected to the main incoming supply and the CT clamps around the grid supply. I’m not an installer but you may need the CT clamps on the incoming supply anyway to ensure that the inverters remain within any DNO export limit.
And having the inverters on separate distribution boards won’t prevent cross charging as both inverters in Eco mode will try to match battery discharge to grid import. and since the two DB’s are wired to the same grid supply, they can cross charge anyway.
And having the CT clamps measuring DB load rather than overall grid load might mean you get more volatile demand on each inverter which will lead to more cross charging anyway.
Cross charging is something you can reduce but generally you’ll have to live with regardless. I get it on my inverters, overnight my inverter 1 will slowly discharge its battery into inverter 2. Its 99.9% that way round and its always a slow discharge so I just live with it.
Thanks Geoffrey that’s good to hear I was going to put the CT’s on the incomer just thought the inverters wouldn’t try to react simultaneously to a power demand on a split load if I went on the RCD tails it’s in the same DB
I have a 5 KW export so am I correct in assuming that I changed the extort to 2.5 KW on both inverters when I comission
I am currently running 1hybrid inverter as a string inverter and the other hybrid with 4 giv 2.6 batteries
Reason behind this post is that I have acquired 4 more 2.6 kWh batteries to get me up to 20 KW storage
My initial set up was 2 inverters with 2 batteries on each but I was told on commissioning that I couldn’t do that but they didn’t explain that I could use 2 CT’ s at the time
Interesting setup, that’s a lot of little batteries!
My own setup is two gen 1 5kW hybrids, each with their own solar panels, a 9.5 battery on one and a 5.2 on the other. Each has their own CT clamps around the meter tails.
The dual inverter ‘plant’ setup isn’t recommended by GivEnergy but it does work OK. There are a couple of considerations, based on what firmware you are running.
If you’re on the original D0.450-A0.451 firmware then both inverters will charge the batteries from solar, and respond to house load, BUT if there is excess solar being exported from one inverter then the other inverter will ignore it.
If you’re on one of the Gen 1 beta firmware’s (I’m currently on D0.187-A0.187 but this new behaviour came in with D0.191-A0.193) then the inverter has a number of new features:
- it has ‘fast response’ compared to 450/451, responds to house load much quicker
- new battery pause control, can pause Charging or Discharging or Both
- has AC charging capability, so if one inverter is exporting then the second will take that excess power and use it to charge its own batteries
Its this latter new feature that can cause the cross charging issue as one inverter sees house load such as a kettle, starts discharging the battery, then when the load demand stops there is a brief period where the battery discharge is being exported. The second inverter sees the export power and uses it to start charging its batteries. The first will continue to discharge and the second to charge. This can happen either way round but in reality I see it happening always from inverter 1 to inverter 2.
You can circumvent the cross charging by setting inverter 2 to a forced discharge overnight at your base load power demand. Inverter 1 will then pickup any load above the base load. It does mean you are not using the full capacity of inverter 2 batteries but it means no cross charging. Or you can live with it as I do.
In reality there is always a slight delay in the timing of the two inverters responding to house load. On the Gen 1’s which are relatively slow, I don’t see any race conditions from my inverters. Sometimes one will pickup all the load, sometimes they share it.
You will find that the data in the givenergy app is screwed though as it can’t cope with multiple inverters supporting the house load. I sometimes get negative figures, at the moment its suggesting I have used nothing today which is rubbish
On your export limit, I think you’d need to set the limit to 5kW still as you want each inverter to stop solar generation/battery discharge if its going to breach 5kW. You only have 1 grid connection and the two inverters are sharing it. If you set each inverter to 2.5 then I think you’ll get an export limit of 2.5kW imposed.
Hi Geoffrey
Thanks for your valuable insight I will check what firmware I am running and get back to you if you don’t mind
i’m a bit busy at the moment so won’t get around to the changeover for a couple of weeks
The reason for the smaller batteries was that if I get a fault on one I can easily bypass and keep the system running so I just stuck with it
Hi Deano,
I have the same setup as you except gen 3 (2 x Giv-HY 5.0 & separate batteries on each inverter). I’ve used Home Assistant to make them work together and eliminate cross charging.
Home Assistant is so configurable you can automate nearly anything, when you add the GivTCP app, Home Assistant can see, and control all of the inverter settings locally (not reliant on any GivEnergy servers or apps).
Then you can create an automation in home assistant to keep the charging and discharging balanced with the logic that should have been in the inverters in the first place!
Although this is the hard bit, the Home Assistant community is vast and helpful with loads of examples and forums to help.
Battery SoC
Home Assistant is phenomenal and thanks to contributions like GivTCP it is truly game changing, even fixing some of GivEnergy’s failings!
I hope that helps if you don’t have it sorted already…
Dan