New solar panels and a PV Grid Tie inverter charging 4 Li-ion batteries - Why is my meter still clocking similar usage? Have my batteries been installed correctly?
New solar panels and a PV Grid Tie inverter charging 4 Li-ion batteries - Why is my meter still clocking similar usage? Have my batteries been installed correctly?
Installation has just (Friday 13/11/20) been completed on my roof in Stockport of 28 solar panels and a PV Grid Tie single phase inverter charging 4 x 3.5kWh Li-ion batteries via a 3kW AC Coupled inverter. The included phone app shows that I am now drawing very little grid power and the batteries are fully charging even on fairly dull days, and are still fairly “full’ next morning. However, my daily meter readings are little changed from pre-solar times which means that my electricity bills will not decrease. I am not particularly concerned with selling power back to the grid as I understand that this is poorly rewarded at this time, but I am worried that the electricity which the sun is now freely providing directly for my consumption will still be charged for as if it were coming from the grid. I was expecting my meter to more or less stand still, or even “run backwards” but that isn’t happening. Is there a way to fix this please?
It’s worth mentioning that if you are concerned about the wiring of your solar panels to your smart meter we’d recommend contacting your solar panel installer who are responsible for ensuring the connection between your panels and the meter are correct.
I spent some time today meeting a professional battery installer and qualified electrician. We had a moment to look at the photos which @dnshorto has provided and I gleaned some useful information.
So what follows is with grateful thanks to Marcus of GMEC ELECTRICAL in Barnstaple:
1: He commented that the current clamps can be affected by the electro-magnetic field from adjacent cables. Your installer decided to move the clamp higher on the live-tail to Position A in this photo:
However, this is still in close proximity to the Neutral-Tail, immediately to the left.
Marcus says he tries to find a location where the distance between the two conductors is greater. I’ve marked B as a possible position.
This would enable the Live-Tail to be reinstalled with the outer plastic casing intact.
2: Marcus has previously installed the same Pylontech US3000 Storage Batteries as you have.
However he has never considered attempting to place them in the orientation shown in your photo above, nor so close together.
I have therefore downloaded the Pylontech Installation Manual from here, and checked to see what it advises. Read the two points which I’ve highlighted:
As originally supplied, these US3000 Batteries have mounting brackets to be fitted horizontally within a 19-inch rack. The positioning of the M6 bolt holes ensures that they are held apart by about 30mm.
If they are to be stacked without a 19-inch rack cabinet, then there are feet/brackets which should be fitted in place of the M6 bolt brackets:
Installation Manual, page-17
These feet/brackets allow up to four batteries to be stacked horizontally, but only two vertically:
Installation Manual, page-19
The reason for these spacers becomes obvious when you read the fault-finding guide at the back of the Manual. It states that the batteries will cease to charge/discharge if the enclosure temperature rises above 50°C.
Given that you have 28 PV panels producing a possible 9.5kW of power, it doesn’t take much to see that this is capable of rapidly charging just 14kWh of storage. And it’s that high current which will cause the temperature to rise.
It’s possible that your Installer has allowed for this and compensated by reducing the maximum charge current being sent from the Growatt Inverter. But that seems to defeat the object of having had so many panels installed in the first place.
Let me finish this particular post by pointing out that it is still early days for installation of domestic battery storage, but there are already in excess of 100 models available in the UK. It simply isn’t possible for every supplier to know how to specify and install all possible combinations.
Everyone is still on a very steep learning curve, and I don’t think that your Supplier should be blamed for failing to get this site optimal. The arrangement is still inherently safe, and will simply shut-down the batteries if the charge current is too high.
It’s much more important that we can share these sorts of details with Installers in the expectation that the pooling of such knowledge will help to ensure better optimised installations in the future.
So what I’ve just written above isn’t enough to warrant an irate complaint!
Hmm… That doesn’t sound right to me at all. It’s possible you might need to have a chat with the support team about this issue. The contact details can be found over here.
It’s tricky to say exactly why this is happening, but it should be possible to fix. Please keep us posted with any progress.
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No worries, @Blastoise186 - I’ve been exchanging PMs with @dnshorto today already, and he’s not with OVO.
Personally, I think this is beneficial. There’s some generic background issues to discuss here.
@Tim_OVO - as he hasn’t got a meter running backwards, can we move this to a new Discussion Topic please? I’d suggest Solar Panels and Storage Battery with Grid Connection because we’re about to have lots more traffic on that Topic when the next Storage Trial commences.
I’d like to put together a couple of diagrams to show the two main methods of doing a grid-connection with PV Panels and Home Battery Storage, but today I’m on my roof installing more PV cables whilst it isn’t yet raining!
In the meantime, can we have some further detail of your particular installation please @dnshorto ?
Is your house connection single-phase or 3-phase?
What is the power of each solar panel? Having as many as 28 is very unusual!
Are they all “south-facing” or are they split into an “East-group” and a “West group”?
Thanks Blastoise186 for your rapid response. I am not an OVO customer so I guess that I would be ineligible for support from that team. My ‘dumb” digital meter which was in the house when we moved in 6 years ago alternates every few seconds between the current kWh reading and the uninformative legend: “rEd”. Does that convey a meaning to anyone?
Here is an extract from a PM to Transparent: My system is 28 JA Solar panels each with a rated max output of 345W, [nominally 9.66kW], Solis 1P8K-5G single phase inverter, Growatt SPA 3000 TL BL ac charger with ShinePhone app, charging 4 Pylontech US3000 3.5 kWh Li-ion batteries. All 28 are south facing.
The solar panel installers gave no information about any limits to panel numbers, or official permissions that needed to be granted. I was unaware of this until today. Although keen on the “green” aspect of solar my primary motivation was preparation for extended power outages given the reportedly parlous state of the UK’s generating capacity, and having experienced them elsewhere. `Hence the battery capacity and maximised panel array. That provision may now be in place, but I was also hoping for reduced power bills as a welcome by-product! The :”diagrams to show the two main methods of doing a grid-connection with PV Panels and Home Battery Storage,” which you mention sound like a very useful resource and I look forward to learning more please. (Maybe re-educating the installation team too!)
Juicy details here… enough to give me one last post before disappearing back on my roof!
Any Grid-connection requires a certificate to be granted by the regional Distribution Network Operator (DNO). This is normally handled by the Installer rather than the householder.
G98 (was G83) is the most common. Export to the grid must be limited to 16A per phase (3.68kW for a single-phase house)
G99 is for export above 3.68kW, and is only approved for single-phase where there isn’t going to be excessive losses at the substation due to phase-imbalance, or where the additional power is useful to the DNO because there are already constraints in the area. The Kaluza Battery Trial with Western Power near Lincoln would probably fit into this category.
G100 is where there is generation above 3.68kW, but the control/storage system will only permit a maximum 16A per phase export back onto the grid. Houses with arrays of solar panels facing east & west would fall into this category.
So perhaps @dnshorto could look through the documentation and find out which of these Standards has been obtained for his site.
I have looked through the paperwork provided by the solar panel people, there doesn’t seem to be any reference to a Grid-connection certificate, but maybe it is yet to be provided as the job was only finished last Friday. I have asked the Sales manager for details. We did have a surveyor who came round to inspect the house and electrical distribution boards before the work was started. I will post details when these become available.
Growatt’s technical man Ben said the clamp installation looks OK. Here are 2 snaps. To the right of the meter LCD panel are 2 lights. The right-hand one sometimes shows red.
