Posted by: @david999

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I need a 3 phase meter I’m told, Scottish power don’t do that it’s my supplier octopus.

Yes, the meter is installed by your Energy Supplier, for which they have to meet Ofgem targets, but also benefit from a subsidy.

Here's a diagram showing 'Who owns What' from the MOCOPA Guide for installers.

A domestic 3-phase Smart Meter operates using Vector Sum calculations.

If you are exporting on one-phase but importing on the other two, then you are only billed for the difference between the import/export readings.

The price of solar panels continues to fall. The major cost of installing more solar panels would be:

• labour charges
• scaffolding hire

The major cost of installing additional battery storage is

• the assembly of the battery unit in a factory
• the on-site installation cost

In both cases it is greatly less expensive if you use a DIY route.

I have experience of directly importing lithium cells from China, adding a BMS of my choice and wiring it all together.
A 280Ah LiFePO4 cell manufactured by EVE costs less than $70. The Chinese Supplier will handle shipping and taxes for you and bill you accordingly.

If you want to pay a bit more and deal with a British company, then you can obtain what you want from Fogstar, amongst others.

Their equivalent of the same LiFePO4 cell costs £100

These DIY assembly routes come out to about half the cost (per kWh) than buying ready-built battery units, such as the GSL ones which @bretix showed us in his photos.

Posted by: @david999

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More solar panels could provide more power but a surplus during summer i cant use and send back to the grid.

That's true. But exporting back to the grid has its own risks.

Either Government policy or a Directive from Ofgem could change the rates which you can be paid.
The financial viability of exporting isn't entirely in your hands.

The UK future grid is being built to have a permanent over-supply of electricity from renewable sources.
Why would a Supplier want to pay you a few pence per kWh when they can get it cheaper by signing up to PPAs with commercial generation sites?
[PPA is a Power Purchase Agreement. Selling those enables an energy developer to borrow money to install solar- or wind-farms]

Posted by: @david999

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Most of what you explain here would definitely be over the heads of the level of so called engineers attending my home.

Five years ago, what I'm writing here would've been way over my head too !

We can't attain Net Zero via the 'professional installer' route.
The previous government demonstrated that subsidising their training is mainly effective in attracting a higher proportion of cowboys into the market. 😥 

In the case of renewable energy equipment (including heat-pumps), the system-design and the quality of installation matters as much as the choice of products.

DIY installations (and partial DIY installations) are achieving far greater success than the professional routes.
And, as you've discovered, the insurance companies don't penalise you for this practice.

There's an untapped resource of engineering expertise in the country, which we need to inspire to get involved.
They are the recently-retired cohort who would otherwise be joining model-railway clubs or restoring steam engines!

@transparent I agree with what you say, locally battery banks are being built, more wind g to Irvine sand currently what are installed only run occasionally at full capacity. What point is there paying me when they can’t use their own and self sufficient has to be the way forward. My garage roof is flat so it’s an easy install and I’m opting for ballast mounts, about the same as the cost of a panel and less work than making a mounting frame.  In relation to additional batteries I could install more downstairs below the ones in the loft but the garage would be my first choice although cold in the winter and perhaps a bit damp air at times. If I put them in a kitchen cupboard ventilation might be a problem. Of course I could assign them to another area of the loft away from the others, perhaps 10 feet. 

Another option would be to fit another inverter in the garage a larger bank of panels and batteries, but the garage is fed by two 2.5 twin earth cables and I don’t think that I could connect to the consumer unit in there to feed the house with that install. 

the last thing is I’m a fit 66 year old and wonder how much longer I will be around.  A great home for the next owner perhaps or I go into my 90s 🤞

@transparent my intention would be to go off grid, ready for when or if I ever retire🤔

However this would have to work around my current ( no pun intended) set up I guess my options would be.

1Sell ll my Sunsynk inverter and) purchase 3 separate single phase inverters? 

2. Going down the route of extra batteries would have to mean a (cheaper)self install. How could I mix the battery if I have 40kw GLS and want to go purchase direct from China - (coincidentally already had a few long winded conversations on watts app with a factory from there but the whole MCs conversation got lost in translation when trying to by solar)

3. If utilising my existing inverter how could I do that?

And finally if I want to potentially reach 60-100 KW for the winter months could this be achieved through solar and what size inverters for each phase would you suggest?

@bretix if you are handy then you never get to retire, I certainly get plenty family work, all free of course but too many folk retire, do nothing and die two years later. I’m going to die on one of my projects.

Posted by: @david999

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I’m going to die on one of my projects.

You're more likely to die from DC because the human nervous system doesn't automatically cause the muscles to pull your body away.
... just a thought ! 🤔 

@bretix You don't replace your existing 10kW Sunsynk inverter.

All SunSynk models can work in parallel with others of the same model.
The wiring diagram is on p.32 of your installation manual 😀 

If you want 20kW max, then you add a second 10kW inverter.

I was just being lazy when I posted the previous diagram using three single-phase inverters.
I created it from parts of two diagrams I'd drew last year.

Any new LiFePO4 battery which you buy/build only differs from the existing GLS models by having a different BMS unit.

I'm currently running a 4-battery system:

• two batteries have Active Balancer units rather than a full BMS
• one battery has a JK BMS, manufactured by Neey
• one battery has a 'JBD' BMS, manufactured by Jiabaida

I don't need to have them talking data to each other, nor to the inverter(s).

When I build a new battery, I use a Smartphone App for the first few days while I work my way through lots of configuration settings that I don't require.
After that, I trust it to continue doing what it's designed to do.

You can test this approach for yourself...
... when was the last time you checked the cell-voltages for your GLS batteries?

I use the same supplier for all my LiFePO4 cells because he's proved himself trustworthy.
Have a look at Xuba on Alibaba and send a message to Brian.

You need to ask his advice and pricing on three issues:

• the cost of the 280Ah LiFePO4 cells (you need 16 for a nominal 52v battery)
• the cost of DDP shipping; Delivery Duty Paid means that Xuba bill you for shipment including all import taxes and VAT in advance
• the shipping route; I'm assuming they will go via South Africa rather than traveling to the Suez Canal via the Yemen coast

DDP is great because your goods are off-loaded at Felixstowe docks and transferred straight to the assigned UK courier, such as DPD or Fedex.

Maritime shipping will probably cost around $280 and take 7 weeks.
Xuba can give you the name of the ship, and you follow it each day using an online app.
Don't choose air-freight. Sixteen cells weighs over 100Kg 😮 

@david999 I almost signed up for an electricians course to help towards retirement and doing my own and family projects, maybe the occasional checks but talked myself out of it. This forum has proved invaluable and as my own projects/improvements go on I'll be sure to post

@bretix just bare in mind that there is diy, and diy that gets you into the deep stuff. Lose your whole house to a fire or get someone electrocuted and just watch folk distance from you as the wolves close in. It’s your home remember.  I lost my dormer roof recently and 250k to repair it and the damage the water did. The insurance had two surveyors out and a loss adjuster looking to mitigate the losses. Thankfully any diy over the years, including a rewire in 2014 passed all the inspections, but I was sweating blood.

Choice of Battery Management System:

If the option was there, I'm quite attracted by the BMS unit which Fogstar have selected for use in the enclosure they supply for self-build batteries. There's a good overview of the Pace unit here by Bec Baker of Fogstar.

However, it looks to me as if the only variant they have is one with all the electronics 'open'. So it needs to be fitted inside the battery enclosure.

My second option would be a JK BMS unit with 2Amp Active Balancing.
These are available from a number of places, including stores on AliExpress.

An 'external' BMS like this is built into an aluminium case which also offers heat dissipation:

A BMS performs four main functions which require it to be sited in close proximity to the cells:

• balance the cell voltages, especially if one or two are accepting a lot more charge than the others
• report the present State of Charge (SoC); although a BMS unit isn't great at doing that!
• stop charge-current flowing to the battery if one or more cells exceeds the manufacturer's maximum spec; typically that will be close to 3.6v
• stop discharge of the battery if the inverter(s) try to take it below the lower specification limit

Those last two functions are for 'emergencies'.
The inverters should have been configured to charge/dis-charge to voltages which are inset from the max & min voltages of the batteries.

I tend to buy a BMS which can handle twice the current at which I would charge or discharge my battery.

Thus if I build a 52v LiFePO4 battery which I want to take up to 100A charge-current, then I use a BMS rated at 200A.
That means the battery can respond to a switch-on surge from my house without the BMS going into a panic and shutting it down!

Don't rush out and order a BMS unit yet.
We have yet to discuss whether you'd like an LCD screen instead of using a Smartphone App when you just want to view how it's doing.

Posted by: @bretix

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I almost signed up for an electricians course to help towards retirement and doing my own and family projects, maybe the occasional checks but talked myself out of it.

To pull the UK towards Net Zero and reduce energy bills, we really need a more wide-ranging skill set than you'd obtain from a course aimed at a single trade.

I have a 'friendly' electrician who comes here whenever I need a change of mains connections, or a full-system check for the purposes of Part-P (Building Regs).
He doesn't understand a lot of what I do, so we drink coffee whilst he asks questions and prods at my ELV wires 😉 

Apart from that obvious legal requirement, I do all my own cabling, plumbing and heating work.

I build external walls with blocks, plaster them and spar them.
I do my own roof work, fix solar panels and cable them up.

I insulate the house, sometimes using an extra internal false-wall to remedy a 'cold spot'.
And I design and build 24v LED light fittings.

I make my own enclosures, fixings and widgets with a £200 3D-printer.

I design and build electronic circuits with sensors, incorporating control-logic using a cheap Arduino module, such as the Nano.

I've bought a TIG welder and learned how to make a joint with aluminium.
It's not pretty, but it holds my weight!

And most of those skills I've acquired within the last 8 years.
Some of this is by online research, and the rest by meeting and talking with others.

But please don't try to pull all of those issues into this one topic, or else @editor will be yelling at us with CAPS ON!

The trick here is to start a fresh topic as required, using a Subject/Title which others can easily find.
I'll then supply links to where you can pick the knowledge or the components you require.

@transparent it’s nice to find someone who has a sense of adventure into other skills rather than stuck in a rut. Aluminium is difficult to weld for most but practice is key and super clean.

@transparent bloody hell you sound like Macgyver 😁

Seriously though this kind of stuff and what you've achieved sounds amazing. 

I've always been 'handy' but more risk averse I suppose and not kept up with what can be achieved especially through forums such as this.

And a £200 3d printer to boot again is another dimension, for another thread.

Thanks @transparent inspirational and educational👍🏻

🤗 If @david999  wasn't so far away, I'd be introducing him to my welder and watching how he welds aluminium.
Yes, I clean it with alcohol, but I've only ever succeeded in joining sections thicker than 3mm.

In reality what the UK needs is incentives to set up community-run multi-skill workshops.
They need to aimed at facilitating the Consumer Transformation route, which is part of the Future Energy Scenarios diagram
Instead of tinkering with historical technology (steam engines!) we should be facilitating the fabrication of technology needed for the immediate future.

There are obviously limits to what I can do here on a forum.
But there are three areas which I think do need to feature in this topic:

• what are the materials and components required to install storage batteries and related renewable-energy assets?
• where am I sourcing those parts?
• what are the tools which I've found are required to do this work?

Some of these issues won't occur to forum members unless I 'prompt' the question by posting a graphic....

😉