Good question this, @Mbu1982 - great to see your green tech in the home: solar and storage!

We do have forum members with solar panels and I’d like to see if anyone has any suggestions to check for this. 

@EverythingNeedsAUserName and @PeterR1947 are often happy to have a look at these solar ones. I hope they don’t mind me tagging them in this one. 

There’s also a similar thread from @dnshorto here:

My trump cards are the new-to-solar @Jequinlan and the smart home guru @ArundaleP. As a group if we can’t advise you of a next step, I don’t know who can!

Hi @Mbu1982 

Welcome and I hope below answers your question:

Yes the PV systems all draw (at times) an amount from the grid.

I have been monitoring mine for weeks and can confirm there are times there is :

A) a trickle from the grid, a cloud can drop PV suddenly and if charging a battery the grid may step up while the battery charge is adjusted

B) a trickle TO the grid, this happens most when PV panels suddenly gain more sun, or when battery is charged.

C) when the battery falls to 4% on my system the trickle to the grid is used to maintain the management of the PV system.

Pretty sure the net benefit of solar far exceeds this gain/loss scenario but it appears to be just the way it is.

Here is my current state and a small flow is going TO the grid...

Interesting!  I don’t have a battery as such although my Leaf is connected in V2G & V2H mode.  Like any other permanently connected device the inverter takes a certain amount of electricity whether on or off, however, when I’m generating more than the house is using, I take 0kW from the grid.  I would make a big noise with Solis, it doesn’t make sense at all.

Peter

Thanks for the responses @Jequinlan @Tim_OVO @PeterR1947 I tend to agree with Peter, in this day an age the switch between should be instant.  When I am generating enough energy or have a battery over 20% I do not expect to have any energy to be drawn from the grid.  Does this happen with all inverters?

Wow that doesn't sound right I'm no expert far from it....... I am in the process of ordering battery installation my fist choice inverter was the Solis 5g.

With so many throughout the world you would think it would be picked up by now sounds like a fault on yours.

Be interested to here what Solis say about the ticket they raised @Mbu1982.

Have you used the new tool below live view every 10sec ..... log into OVO it's at the very bottom of the first page

@davericho can you let us know which battery system you’re going for?

@Mbu1982 are you aware of this new 10 second portal view?

Thanks @Tim_OVO @davericho No response or answer yet from the ticket raised.  It makes no sense to me. Even on the days where the battery was at 60% when the sun rose and full charged by 11am. We still used enough electricity to be charged just £0.89 Plus the standing charge. As technology is seem less these days it makes no sense. Will let you know when I hear back from Solis.

Thanks Mbu1982 really would appreciate your Solis update.

Clutching at straws but have tried disconnecting everything to see if you draw power you may have done this, forgive me if I missed you had.

@Tim_OVO 

Hi Tim I will be installing PylonTech US5000 4.8kWh along with a Solis 5g inverter 

Not yet installed 

Thanks for confirming, @davericho - I’d love to hear back from you post installation so we know how it went, any unexpected complications or pleasant surprises. Do you need to let the DNO know?

This is also something I’m keen on hearing back on @Mbu1982...

My installer says my system does not require DNO approval @Tim_OVO certainly update you when installation done, also I am on the old FIT generation covered by Ofgem

I have a new solar system, so this is my first few months of production. That being said, I did a lot of research before installing my system (I tried anyways, some of it doesn't make sense until you have a system installed), and I have a spreadsheet every month of exports from an emporia energy monitor (CT's on individual circuits and my mains) as well as an export from my inverter, and an export for every 15 minutes from my power company. All the data is within 2-3% accurate of each other for production/consumption.

@charjes9 nice to hear sounds like you have a good system, was your system installed by a local company? how many panels do you have, and be interested to know what inverter, and do you have a battery installed.

Bet your looking forward to a good summer like this year  

My Luxpowertek inverter also imports power from the grid every day. The average over the 3 months since it was installed is 0.26 KWh a day.

My neighbour, who has had solar pv with batteries for many years, warned me that the system would import from the grid when there was a sudden demand for power from the house while the batteries got up to speed ie because the batteries are slower to react than the equipment using the power.

Yesterday the system imported 0.2 KW hours in total, mostly when there was a spike in demand which exceeded the solar power being generated at that moment.  The demand was from the electric hob.

The system also imports small amounts from the grid for no reason that I can see, usually when the batteries are charging. Yesterday,  for example, it imported 109 watts when the data showed the system was generating 1796 watts, the batteries were 91% full,  the load was 177 watts and the charge going to the battery was 1691 watts. The load remained steady before and after. The readings for the power generated and the charge to the batteries, when it imported the 109 watts from the grid, were more than the equivalent readings before and after.

Is it something we have to live with, or can the inverter and battery technology solve the problem or does our domestic electrical equipment need rethinking to work in synch with solar PV systems?

So far (fingers crossed) the savings from my system far outweigh the cost of the imports.

Thanks @maryjay appreciate this I haven't had mine installed yet but will bear in mind what you have noticed on your system if it happens to me.

Hi @Jequinlan. New Solis system installed on Friday. I wonder if you would know why my system is exporting to the grid when the batteries are not full? 

Hi @downing123 I don't understand this myself but my Solis system is being installed in 2 weeks time so will look out and see if mine does like yours

It is worth noting that most (if not all) inverters do not react instantaneously and so if the sun disappears behind a cloud, there is a balance needed to control power from solar PV into/from batteries and to maintain supply from the grid - this is where there can be a feed back to the grid at time while the system is balancing. 
​​​As @Jequinlan mentions, these flows are normal but overall the system does what is required. 
I’m sure in future systems will be able to respond much faster on switchover. 

Another thing to consider is that batteries have a maximum charge rate. If your excess solar PV (over the amount being used by your house) is more than the maximum charge rate the excess will go to the grid, even though your battery isn't full.

Hi, I have a 3kw PV system that’s 8 years old which was using 3x basic inverters so have changed them out for an 8kw solis 5G and 2x Basen green 51.2v 100AH batteries in parallel and I’m at my wits end with it to be honest. The batteries don’t seem to communicate with each other to balance charge or load, once the batteries are getting low SOC the difference becomes too much for the inverter  and it gets muddled which one to read and what to do. I manually charged both batteries to 100% over the weekend and disconnected them from the inverter to let them balance voltages as per my suppliers instructions yet today one is down to 17% and the other 31% so the inverter wants to charge from the grid because of the 17% battery being below the 20% minimum SOC that’s setup but then it reads the SOC of the 2nd battery at 31% so switches from charging the battery to using the battery for a few seconds until it reads the 1st battery so reverts to charging again and round and round this cycle goes. 
 

My current desperate move is to remove the CAN link between the batteries so that the inverter only reads one of them but I’m worried that once the better weather comes round it might over charge the battery that doesn’t have a CAN link.

Hi @Frazzled you need to be very careful with the charging of Li-ion batteries as they can become unstable. I’m assuming that your Solis inverter knows which batteries are connected (or similar) as most systems have a variety of parameters to chose from depending on their connections. 
There is also a primary battery to be designated when you have several connected. 
Do you have a schematic of the system perhaps?

Edit: I just found this battery compatibility list from Solis and I can’t see Basen listed https://www.ginlong.com/Uploads/file/Compatible_Battery_List_aus.pdf

I have them setup as battery 1 and battery 2, my supplier assured me they were compatible

My inverter isn’t on that compatibility list, I have an S5-EH1P6K-L, not an RHI inverter. 

Basen is still not listed on the Installation manual