On-grid domestic battery storage 5 December 2016 at 3:57PM edited 30 November -1 at 12:00AM in Green & Ethical MoneySaving 1.9K replies 203K views

chamelion

joefizz said:

diveleader said:

The Powerwall has twice the capacity, better thermal management and can go in the garage.
The Pylontech's are modular, so easier to expand, replace etc. but have to go in the house.

What would you do?

Sorry, coming to this late. Same choice I had. Pylontechs and inverter can also go in the garage AFAIK as that was one of my choices but I chose to install in the spare room to use some of that residual heat to reducing the heating required in that room.

Leaving cost aside I went with the pylontechs purely because of the modularity and knowing that at some point they will fail or a section of them will fail and my thoughts are that they will be easy to replace. Both pylontech and powerwall are effectively large banks of smaller cells but for me it was easier to take one of the pylontechs offline, fix it and then replace, rather than have to fix the whole thing. With the powerwall (or LG etc)  its a nice neat all in one solution but it also a single point of failure, and whilst separate inverters and batteries are also single points in themselves, easy to get a replacement (or different inverter entirely but use the same batteries).

Check out the inverter oversupply capacity. In some this is as much as 20% so a 4k inverter might take 4.8k peak which might be all a 6k array ever puts out in your orientation. The numbers are just nominal, it will depend on your situation and siting etc.
You can always add extra panels on to the end of your strings (I did) after a year or two of usage so you know the max your system tops out at at the end of June.
I started with 4.8kw pylontech and then doubled it for a number of reasons, found I could use more in summer (hot tub, beer making etc) so could use the extra capacity, modularity and for the rest of the time, spreading the load across more batteries, hopefully extending life a little more.

How did adding panels impact your FIT? 

joefizz

chamelion said:

How did adding panels impact your FIT? 

I live in NI. Different system. Depends on your total inverter output here (or did when I signed up). Get them signed off and you are good to go so I bought from my original installer.

frugalfran

Our house has solar panels (fitted years ago at a very good FIT rate) and, more recently battery storage (ESS). 

We had a power outage not so long ago, the batteries swung into action, we had no idea  it had happened.  The local energy network folk arrived, saw some houses with power, some without and assumed our house was on the same circuit as others with power, fixed the problem as they saw it and left.  Only the following morning did we realise there was a problem and they then had to return and fix us separately.  This involved digging up part of our front lawn, the neighbour's pavement and two full days of work.  All of them were very much interested in our system - all the top honchos turned up on the second day, keen to discuss it all with us, as the regular crew were apparently not sufficiently trained to deal with complexity. 

Could anyone please tell us if Smart Meters are compatible with all this stuff.  We find that all the facts and figures  provided by the software would be hard to improve on, but there are possibly cheaper tariffs for the future most of which have smart meter acceptance as a condition. Having seen the reaction of the energy network's best team,  I am concerned that the smart meters fitters would not fully understand the complexity of the system and could cause harm to our installation and investment which focuses on reducing our carbon footprint.  We are already in the low consumption household band.

EVandPV

frugalfran said:

Could anyone please tell us if Smart Meters are compatible with all this stuff.

No problem at all. 
We have an ac coupled battery and had a smart meter fitted a few months ago with no issues.
Naturally, they need to turn your power off at the consumer unit but the job doesn't interfere with your battery or pv system at all.

Pulpdiction

Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

Thanks

chamelion

Pulpdiction said:

Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

Thanks

Just for clarity - you use 8400kwh a year? so approx 23kwh/day on average? 
Any way of knowing how much you're generating? 

Pulpdiction

chamelion said:

Pulpdiction said:

Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

Thanks

Just for clarity - you use 8400kwh a year? so approx 23kwh/day on average? 
Any way of knowing how much you're generating? 

Hi, 3,250kwhs per year on average over last 5 years generated.  The 8,400 is the forecast usage on my latest electricity bill. With 2 teenagers in the house I'm guessing this is way beyond average, but would also take account of the electricity I've generated and used.  Like most I don't think I am getting best use out of generating in the day and then not being able to use that in the evenings.

JKenH

Pulpdiction said:

chamelion said:

Pulpdiction said:

Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

Thanks

Just for clarity - you use 8400kwh a year? so approx 23kwh/day on average? 
Any way of knowing how much you're generating? 

Hi, 3,250kwhs per year on average over last 5 years generated.  The 8,400 is the forecast usage on my latest electricity bill. With 2 teenagers in the house I'm guessing this is way beyond average, but would also take account of the electricity I've generated and used.  Like most I don't think I am getting best use out of generating in the day and then not being able to use that in the evenings.

If you are consuming 8400 kwh over and above your generation there is a good chance you are consuming a big chunk of what you generate alraeday and there won’t be much surplus to go into a battery. 

I think the first step would be to establish how much of the energy you generate Is consumed in the house. There are numerous devices available to help you establish this. I have a Myenergi hub which was installed with my Zappi EV charger and that monitors the consumption and generation. 

I find I am using more of my generation than I realised, typically 15 kwh a day without the  EV charger. If you imagine that your base load (what you use all the time to run fridges, freezers, devices on standby) is say 300watts then during daylight hours you are using 3.6kwh from your panels (a bit more in summer/bit less in winter) without switching anything on. Add in kettle usage, washing machine/dishwasher, water heating and cooking (if electric) and you will soon use up what you generate most months of the year.

Pulpdiction

I think the usage has gone up due to 2 of us working from home and kids out of school, its probably about a third more than it was forecast to be, I;ll try and find out some historical numbers.

Pulpdiction

Pulpdiction said:

I think the usage has gone up due to 2 of us working from home and kids out of school, its probably about a third more than it was forecast to be, I;ll try and find out some historical numbers.

So more like 25% increase in last 3 months, so ideal time to take a look.  The problem is we are consuming in the evening and not that much in the day, so ideally I can store in the day and use later on.