I don't know what I am doing...

Hi all, please don't crucify me...

I've had my PV (26 x 400w) and batteries (2 x 9.5KWh) hooked up for about a month but looking at my app, the system seems to be doing some very strange things...

Like right now, I'm apparently still getting single digits PV from the moon (I guess that may be a thing), and while I have amassed 18% of my 19KWh capacity today, my app is telling me that I'm not using it and I'm still drawing off the grid. The load is only 4/500 Watts so why isn't my battery doing its job properly?

I've also seen it working to power the house and sending additional power back into the grid... why would it do that when it's only maybe 10% charged?

My system is an AC coupled system with 2 x Fox inverters between the Givenergy Inverter/Givenergy Batteries and the PV.

Any help for resource to understand my system better wouldn't go a miss, or any advice on how I can set it up or utilise the app better to give me more control or more intelligent control over my power would be greatfully recieved.

Firstly, make sure it is on ECO setting.

Secondly, don't believe everything you see. PV and Grid are measured using CT clamps which are not 100% accurate. The single digits PV at night can be ignored, for example. The inverter does not react to changes in generation and load demand instantaneously so there will be times when the app and portal especially will show misleading numbers.

For example, take a day with sunny periods - clouds go in and PV drops to a few 100w - sun comes out and jumps to 5kw. At that point the inverter will take a few seconds to react and ramp up a charge of the battery so the numbers may show the 5kw being exported - but not really. Equally, background load for your house might be, say 400w, turn the kettle on and demand jumps to 4kw. The inverter takes a few seconds to ramp up so the app shows import from grid of 4kw - but not really!

You will get used to it - we've all been there. I've lost count of the times I've said to myself 'What IS it doing????' But there's rarely a real issue and all is well. Always temper your views with a sobering look at your smart meter. It will reassure you that you didn't really export all that PV to the grid instead of charging the battery. Or cook that whole meal in the oven from the grid.

BigAl My system is an AC coupled system with 2 x Fox inverters between the Givenergy Inverter/Givenergy Batteries and the PV.

Is the PV and old FIT installation or is all the equipment a new installation? It doesn't really matter except that if it is a new installation, then using Givenergy Hybrid inverters (HY5) would have reduced the cost and the number of inverters and therefore the inverter losses you are dealing with. Anyways ...

Do your Fox inverters (presumably there's a Fox app or portal or something) appear to be working as expected? The last week has been poor for PV but yesterday was very good for us.

Do you have a time of use tariff to charge your batteries up on a cheap rate? As @cluelesscris says, make sure your AC3 is set to ECO. In that mode, it should divert any grid export from PV to battery and supply any house load from battery by minimising grid import. I'm assuming you have only one AC3 with your two Batt9.5s? The key will be to ensure that the AC3 is responding to grid import/export by discharging/charging the batteries. Once you've got confidence in that, you should be able to relax. It's feasible that your grid CT may not be the right way round, but you'd need to do some testing to be sure of that. It is quite normal to see "worrying" grid import and export for a few seconds after an appliance is switched on and then off as it takes a few seconds for the AC3 to respond.

Do you plan to use the AC3 purely to soak up excess PV or do you plan to charge off-peak and consume entirely from battery?

One of the issues with using the App/Portal is that it's taking a 10 second snap shot so it's not entirely accurate

I've added a Shelly meter with clamps to the panels and grid supply which measures in real time. The system is behaving much better than the GE app would make you think.

One thing I did notice is how the Solar panels/Inverter actually consume a tiny bit of electric once the sun goes in which is why it looks like the Moon is providing you with a bit of energy. The figures are actually -50Ws etc which I'm assuming is just the way the inverters capacitor discharges itself. A bit like how a little LED from a charger might still light up for a few seconds after you turn the socket off

Tim
Nah its all brand spanking.

Think I got palmed off with 3KWh gen 1 inverter... oversight on my part if that is the case.

The Fox inverters are currently both offline and doing bugger all so it's time to get someone out to
a. look at this system and
b. do an actual handover to show me how to use monitor and set it up to my needs...

Starting to think this company came from the wild west...!

Still on a fixed 17p tariff until end of Jan so when that gets here I'll jump into an off peak one and hope that Givenergy have sorted their smart features to predict the weather and charge my battery when the going is good.

BigAl it's time to get someone out to

You haven't specified the exact model for each device and I'm not familiar with Fox inverters, but you seem to have sufficient inverter capacity for your PV and you have sufficient battery capacity to sink surplus PV there but if you've only one AC-coupled inverter, you've missed an opportunity to charge both batteries during an off-peak window. In the summer, you could have the full 10kW of PV and only one AC3 to divert to battery; the rest would be exported. You'd need over 5 hours off-peak to fully charge the batteries from a single AC3 whereas if the Fox inverters had been replaced with Givenergy HY5s, each could be connected to one of the batteries and you'd double the potential throughput and reduce the number of inverters at the same time. ATM your single AC3 can support 3.6kW of house load from battery whereas if each battery was connected to an HY5, they would support 7.2kW of house load; more if there's PV available as well. Daisy chaining batteries off an inverter is a supported configuration but is more complex than having one battery to each inverter.

As soon as you have your system working, it's worth looking for a time of use tariff as charging off-peak and supporting house load from battery can be done at the off-peak rates. These vary from 4.5p/kWh (EDF EV tariff not currently available though) up to about 15p/kWh (Economy 7 so plenty of time to charge on an AC3).

Hope you get some decent support from your installer to get everything working properly.