The Solar Thread

I’m a little confused with regards inverters, I’ve got a 5kw inverter, 5kwh battery and currently 3.2kw of pannels (8×0.4). I am considering adding more panels, but is it pointless adding more than another  1 8kw of panels?  also grid connected for export if that makes a difference

But what can I say….. No one’s ever checked – which is probably why they want to insist on point one beinga hardware limit because I for one would have no qualms pressing a few buttons and making full use of the Hardwear.

To be fair this led to an argument with my installer when they told me that the inverter settings would be locked behind a PIN that they refused to divulge, in case I changed the export limit.

Anyway, this is a very good example of why you never pay in full up front for any electrical work.

Second installers compromised with me and said that the DNO requires a PIN, but nothing says that it has to be changed from the factory default setting.

If you have space go for the most amount of panels you can – panels are cheap now. 60-80 quid a unit for the standard stuff.

You’ll be clipping in summer

But in lower light conditions each panel will produce a given % of rated amount.

So your total production in lower light conditions will be better – and that area will be will be where you most need the production most likely

To be fair this led to an argument with my installer when they told me that the inverter settings would be locked behind a PIN that they refused to divulge, in case I changed the export limit.

Well in my inverter that would also prevent me from changing import export limits. They can get to buggery with that.

Ah, that’s a bit less generating capacity so you have to be a bit smarter about load shifting to make the most of it. Solar water heating, running stuff in the daytime etc which is more labour intensive than just exporting.

If you’re already with octopus you can run the Compare app to see which tariff works best for import, but it doesn’t account for generation so it’s limited use.

Tracker + fixed export may work better than flux if you can keep out of the peak evening window

This was a day in June last year showing the effect of the inverter limit. To be fair, it doesn’t happen all that often, because we have an E/W split, but we were restricted for about 4.5 hours that day for example.

I think our limit is hardware rather than software.

We took the attitude of more panels for the reasons above. On a normal grey day, we will still produce 5-8kwh.

We are already clipping in the middle of the day in full sun, which is the downside!  Our set up is 5.2kw facing straight south and then 1.6kw facing east and 1.6kw facing west.  Whilst we bump up against the 6kw inverter in the middle of the day, we start quite early and finish quite late.  February was our first month of having it, we produced 305kwh in North Yorkshire

But inverters are cheap relatively, in 5-10 years maybe stick a 8 on if they’ve upgraded the network or changed the rules. Then we will have sufficient panels.

No it’ll be export capped at 6kw.

Explain that to me then…. How does that work?

If the inverter doesn’t limit what goes to the house how does it limit what goes to the grid?

Serious Q as I thought all inverters just converted the DC to AC and sent it into the “house”.  Anything the house doesn’t use naturally goes out to the grid.

If the inverter doesn’t limit what goes to the house how does it limit what goes to the grid?

You don’t have batteries do you ?

A hybrid battery pv system constantly monitors generation (natively) demand and export via CT clamps.

It knows how much the house can have it controls how much can be exported and manages it based on the settings.

It has to Otherwise your Batterys would just drain to grid.

If the inverter doesn’t limit what goes to the house how does it limit what goes to the grid?

The inverter measures the electricity flow in and out of your house. If it senses electricity flowing in, it’ll increase its output (drawing from the batteries if necessary) until the incoming measures zero, or it’s reached its physical limit.

For exporting power to the grid, it can have a different (lower) limit and it’ll just put power out to reach that limit and no higher. If there’s spare solar generation it’ll go into the batteries, or your hot water tank, or ultimately it’ll just be ditched as heat.

so with 8kw panels and 5kw inverter I could export 5 and use 3 in the house ? or visa versa?

No. With a 5kw inverter the max you could use from the panels is 5. So 3 to the house then 2 to the grid. For example

Ok, updating this with details from our installation.

Panels: 16x 415W panels with a 6kW Inverter. Max effect approx 6.64kW. Total cost (including tax rebate for installation of green tech) 81K SEK, so about 12.1 k SEK per kW, roughly equivalent to 916UKP/kW.

Battery: 1x 5kW base unit (Huawei) with Luna2000 control module, plus 1 x 5kW (total of 10kW). Total cost, including in tax rebate for installation of green tech) approx 57k SEK, so roughly 4.4 kUKP.

Total installation is therefore about 138k SEK or about 10k.5k UKP. It’s a big chunk of cash, but el is only going to get more expensive and it does mean we are a little more self sufficient.

The green discount is much more heavily focussed on the battery (it is effectively half price with that factored in) which is the reason we stretched to 10kW. We’ll see if the panels actually fill that in summer with, given the S/SW orientation of the roof, should be possible.

It’s a big chunk of cash, but el is only going to get more expensive

I thought prices were coming down?

Seems quite good value for money to me.

to those wirh octopus, how often do you get export credits on your bill?

Under the Charges in detail section any export shows as “Outgoing export” and details the amount immediately below. It mimics the electricity and gas segments of the bill.

to those wirh octopus, how often do you get export credits on your bill?

Monthly

Hi, Australian solar performance here. Most people have panels on their roofs. I’m running 4 strings facing north, east and 5 degrees south totalling 18kw, 2 x Fronius inverters totalling 13kw and 14.5kwh powerwall. On the demand side I’m running air source heating and cooling, as well as an ev. Savings on paper are $4k per annum on a total system cost of $20k. If I add in ev charging savings and firewood savings, that doubles to $8k per year. 

Finally got the system up and running after confirming that the meter was configured and our supplier had ok’d things. Not the sunniest day for a start, but currently getting 1.2-1.8kW from the panels and managing to export a bit to the grid. Still not exactly sure why the panels/inverter are not charging the battery, but…

GF has not yet plugged the car in to charge, but that will be an interesting experience.

Mega day on Agile just finished…. Average price has been about 0.6p/kWh (not 6p) or less since about 10pm last night.

Got a full tank of water at 65c, house (place by the sea which is all electric) up to 20c and a 3 loads of washing done and tumble dried!

Happy days 😁

A question to those with the Huawei Luna equipment… Is it a user config setting, or a network setting that allows you to charge the battery overnight and then discharge at peak cost? Or is it just going to default to charging from the PV?

I’m staring out into heavy overcast and wondering when I am going to see full flow on the panels…

https://www.accc.gov.au/media-release/proposed-compulsory-recall-of-dangerous-lg-solar-storage-batteries

See oz going mad for it with the LG battery recalls looking to make it compulsory due to a high proportion of fires traced back

Christ a light thats worrying

it reads like an issue with a specific batch or something?

Makes a little scooter battery seem a bit insignificant!

there are a not insignificant significant number of voluntary ongoing mfg recalls for LG equipment – but you’d have to search to know about it – has anyone had any contact from their installer since they installed ? Many installers have gone to the wall over the last couple years with cashflow issues and price rise problems so the chain is broken.

I’ve certainly had no follow up contact from either installer i used since install.

the big deal here is that the oz gov are trying to force a compulsory recall.

I’ve got those batteries.  I’ve not been contacted by the installer though he is still in business.  I’ve since checked them and they are seemingly not part of the affected batch.

Stories like this have actually led to me moving my untidy stack of batteries out from under the stairs and into a new and shiny metal tower into the garage. Not cheap to change (£2,500), but it did require a new inverter and fourth battery + DNO notification.

On the bright side I got a phone call from the installers asking if I’d be happy with the 6kW model as a free upgrade due to stock problems, so in the near future I can have Powerwall-style UPS for the house.

Am I right in thinking additional batteries are VAT exempt?

We have an 8.7kW battery and I would like to add another 4kW (DIY job) Can I purchase the additional module VAT free?

I understand they are now VAT free, but i know on my Giveenergy setup i canno0t add a battery without it being recommissioned by a registered installer, or have access to the installer’s login to set it up, which obviously i don’t have…

Stories like this have actually led to me moving my untidy stack of batteries out from under the stairs and into a new and shiny metal tower into the garage. Not cheap to change (£2,500), but it did require a new inverter and fourth battery + DNO notification.

That was the primary reason for me installing mine outside.  Is it likely to go wrong?  Probably not, but would it play on my mind?  Definitely.

I’ve boxed mine in to keep the rain, sun and frost off them and have added some fireproofing to the enclosure.  On a very hot day, I’ll open the doors of the enclosure…I could do this automatically with one of those greenhouse mechanisms, but I don’t see the need at the moment.

I understand they are now VAT free, but i know on my Giveenergy setup i canno0t add a battery without it being recommissioned by a registered installer, or have access to the installer’s login to set it up, which obviously i don’t have…

Have you checked that the login details aren’t the default ones or that its something postcode, phone number or customer ID related?

Installing a solar battery is a doddle.

you cannot buy them vat free as a consumer.

But in reality theres no such thing even through an installer . The price you can buy them at off the net is less than you’ll be getting sold them even VAT free from an installer and then fitting on top.

see also this weekends chat every where about the updates to the BSI advising you dont install batteries in the loft.

If i fitted mine outside – there would be 6 months of the year i could not charge them at night and 3 months i could not use them at all – as well as them being a high theft target in a rural location.

mine are bolted to the gable end brick wall and as far away from habitable rooms as possible + i have egress windows on both upstairs rooms.

be interesting to see what my insurance renewal has to say on the matter now that the guidance has been published through.

If i fitted mine outside – there would be 6 months of the year i could not charge them at night and 3 months i could not use them at all

How so?

interesting trail rat. Ive not been asked about my battery installation at all by my home insurance!

How so?

Temperature.

Are you not in the UK or do they have a really small operating window?

Mine seem to work just fine in anything from -15 all the way to +40.  The inverter makes more noise when it’s hotter, but the batteries just sit there quietly doing their thing…

Are they  life4po ? And have they got on board temperature stabilisation.

On life4po and without heating Anything below 10c ambiant and high charge rate.  bit like driving your car everywhere always in 5th gear

My batteries throttle back below 10 down to 0 charge at 0c for self preservation. Reasons

yer the new advisory about location

I considered hard when i had mine installed in August, and went loft, actually the ideal location would be the shed at the bottom of the garden

I read that storage is pretty safe, and Lifepo4 even safer