DUAL BATTERIES AND INVERTERS

I have 2 gen3 inverters each working with one 9.5 battery, I have to log in to each seperately, the way Giv suggested.
As a consquence I get 2 streams of data which never seems to agree regarding grid input, battery discharge or solar input, is each inverter using different amounts of grid.
They are both set up to work with Flux so charge 02.00 to 04.00, I had them both dicharge at 16.00 to 19.00, both batteries went from 100% to 4% but didn't supply 4kwh as expected even though the power was exhausted from both, can't find any export evidence either.
I was expecting the 2 inverters and batteries to act as one unit, has anyone any experiance of this.

I thought GivEnergy did not support dual inverters due to cross charging.
I think you need HA or something

They do support Dual inverters. They just don’t recommend it at the moment due to the cross charging issues. Which can be managed by other means. I guess they’ll remove the “not recommended” once they have their CEMS on the market.

Pete UK Thanks, you'd think Giv wouldn't recommend something they dont support, was installed Dec 23, been away so only had 2/3 weeks to try and make sense I've contacted Giv awaiting response.
What is HA, sorry novice.

NUTTY home assistant. There are some software scripts which help keep batteries balanced

Smk82 okay thanks

It depends what Gen inverters you have and what you are trying to do with them.

There is a risk of cross charging as others have said whereby one inverter will be discharging and the other charging.

I have two Gen 1 hybrids and they work pretty well together, there's only one specific circumstance where they will cross charge, if you're just setting Eco mode most of the time the two inverters play nicely together, sharing the house demand between them. If they are both set to force charge or force discharge at the same time then again they work fine together.

The issue comes if you try a charge to a certain % SoC and one battery is above that Soc and the other below. This happened to me because I had dissimilar battery sizes. There are ways around this with home assistant for example - basically you turn off discharge during a charging period.

I believe the gen 2's and 3's may not play as nicely together as the gen 1's, but I don't have details, sorry

I have gen3 inverters which where swapped by Giv from gen2 as they where having problems commissioning, so now I have a cross charging issue which Giv are thinking about, some suggestion of adding an EPS and maybe additional consumer unit.

I can confirm that a pair of Gen 3 hybrids will cross charge each other in ECO. I had this issue. One will charge into the other until it’s full then they will swap over, or they’ll swap over when there is a change in demand or solar generation. They basically see each other as a load and one will battery will discharge into the other to fulfill the “load”.
I’m sure this is why it is currently “not recommended” (although they are supported !)
You will need to find some way of controlling them until GE release their CEMS, which looks like is a fair way off.
Currently you have the option of using Home assistant, other similar style software, get on the beta trial for the hardware CEMS or get on the beta “balancer software” trial.

GE are aware of the cross charging issue with dual/ tripple inverters.
I don’t see how adding an EPS or extra consumer unit will do anything to help the cross charging issue.

I think it ought to be possible to remove this problem with a relatively straightforward firmware fix, but I obviously have to make a number of assumptions in saying so. I only have one inverter, but I do have a zappi EV chargepoint which can charge from excess solar, and because the installer didn't set up the CT clamps as I requested, it can drain the GE battery in exactly the same way if, say, the sun goes behind a cloud.

I assume that, in order for a pair of batteries to interact in this way, the inverter must be set up to spontaneously consume any "foreign" export is detects. I hadn't realised they would do this. I assume that this has to be an active move, ie there are separate DC to AC, and AC to DC converters, rather than one magic circuit that can operate in either direction. and so to consume this unexpected export, it has to actively turn on the AC to DC converter.

So if there was just a register setting that could tell it not to do this, the auto-discharge shouldn't happen. However, with this, you do lose one benefit: when one battery fills, its inverter will export excess solar as AC, and it would be nice for the other inverter to consume this. We can keep this benefit by using a tunable register, rather than a simple boolean.

The Zappi has an "export margin" parameter which tells it how much export to "leave on the table". This is how I stop it draining GE battery. Eg if battery is full, it exports excess solar. The zappi grabs most of it, but allows 100W to escape. If the sun dips, the GE will briefly discharge battery to make up the loss. But because the zappi isn't consuming it all, the GE will reduce battery discharge, and it will end up back at zero, with the Zappi once more only consuming (most of) the excess solar.

I think this mechanism can also be used to prioritise consumers of excess power: the one with the smallest export margin will get first dibs on any exceess power.

Pete UK I don't know why eps was suggested, I think seperating the inverters and batteries so they operated as individual installations was behind the additional consumer unit.
My problem I guess is I'm obviously out of my depth with the tech, half the time I have no idea what people on community are reffering to when they use abreviations so its tricky for me.
I'll try Home Assistant and keep nagging GE.
Thanks for the reply it is helping me get through the fog.

DD GE are trialing a fix or testing internally, there was a suggestion they may see if it works on my system, you guys obviously understand the tech behind this which I unfortunatley don't so I'm going with "wasn't fit for purpose" as a promt to get somewhere.

NUTTY

If they offer you an opportunity to get on one of the trials; Jump at it ! In fact ask them for it ASAP.

I’m on the Beta trial for the inverter “Balancer software”. It is working very well and I’d say it’s reduced the cross charging by about 97-99%.
It’s not really noticeable any more and when it happens it’s only for a short duration, or it’s because one battery pair has a higher voltage than the other pair and I suppose it’s “balancing” it out, as intended.

Pete UK Thanks, I've contacted GE to get on the trial, will let you know what if successful.