@Thebeeman

[sharpener]

So for example in EPS mode my inverter will supply a maximum of 2.5KW even though the system is able to do 5KW when the grid is up.
...
I could be totally wrong and am interested to know if I am misunderstanding this as I find the 2.5KW limit a little annoying!

I think this is a feature of (for example) Lux inverters, not an inherent limitation.

The 2 x Pylontech batteries give me 74A which provides ~3.75 kW. If I were to add a third it would be 100A (limited by the battery plug/socket connections) but only 4.4 kW net (max island mode output of the inverter) so not worth doing on that account.

[NoraBatty]

Hi, newbie here after advice please.

Scotland, Aberdeenshire, electric only,
12kwh heatpump
DHW via 200litre cylinder, 1 weekly immersion heating and midweek top up with heatpump

Incoming supply 1 phase, 100amp
TN-C-S
Approx 5200kWh yearly consumption, (based on last year, moved in jan23, alot of inefficiency found, so probably less)

Typical load profile house occupied all day and night. agile tarriff, avoiding peak usage 8-10am and 4-7pm. Heatpump is agile linked, avoids peak time.
day time - TV, PC, Fridge, 2 freezers, internet, kettle, electric oven/airfryer/induction hob, 12kwh Heatpump (winter)
7pm until midnight- TV, PC, electric heated blanket, 2lights. then off at switch, not standby.
7pm/7am- 12kwh Heatpump (winter), fan (summer) Fridge, 2 freezers, internet
Usage 7pm-7am can vary from 2kwh, to 20kwh on average, summer to winter..
Usage 7am-7pm can vary from 2kwh, to 20kwh on average, summer to winter..
Dishwasher/washing machine eco modes, i,e 0.8kwh per cycle. Timed for best energy price, normally 2am ish 2x a week

Summer, we are finding during the day we mostly are covered on existing solar and export, unless cooking. Night we have to import. Obs.

PV setup
7x395 Canadian solar panels on 2 strings, 3x se facing, 4x nw facing
Solis 3kwh inverter, grid tied, no battery. annual yield (calculated at 1887 kWh) actual is running at 645kWh. we have issues to be fixed.

work during a power cut. Yes

Do you want the batteries to supply the loads in a power cut and for how long
(a) all loads. Ideally as long as possible.,realistically,Only few hours and we can isolate circuits at CB to extend battery time. Enough to cook with, keep fridge/freezer going and get house to temperature, although we have an open fire if desperate. We do not seem to exceed 5kwh load at any time with normal living and with heat pump running. Also on priority list, but it took 3 days recently to get an emergency generator.

Anything out of the ordinary for a normal domestic setting
No.

Gable end points ssw. Plan to put max 6x425w, on vertical wall/90degree incline.
Plan a large garden workshop that will also face ssw, add 5+ panels on it depending on size.

Current solar does not function as expected.
Previous owner who had the heatpump and solar installed on a government eco grant, has stated these initially were wired as one string,
Despite this, in may 22 he was getting over 1.5kwh exported at mid day.
As soon as they changed it to 2 strings, given the 2 different directions on the roof, he was only seeing a max of 500Watts a day from both combined.

This tracks with what we have seen this past year. We will have someone look at them and add optimisers if needed, despite no shading on either string. Personally i would like to upgrade to bigger output ones if possible in the same size, and squeeze 1 more panel on the 3 panel string.

The heatpump gives a scop of 3.5 according to our monitoring app, and we currently are missing pipe insulation, some loft insulation, and suspended floor insulation.
My father was a plumber and i learnt alot about the trade. I have found constant pressure drops from untightened compression joints, excess pipe runs, and floorboard screws through the pipes. The original installers have been called back 6 times and i am still finding issues with their work. Flow rate is constantly low, so i will be having the plumbing ripped out and done properly in summer, along with the missing insulation work.
This should reduce our consumption and increase efficiency.

Current solar is MCS accredited and G98 approved.
We are looking at getting an electrician in to swap the solis to a 5kwh inverter and adding batteries and extra solar ourselves, up to about 20kwh, to maximize our low agile prices, to keep the heatpump running in winter and get some pennies from export.

I am yet to ask the DNO if we can upgrade to 5kwh, but will enquire this week. I presume a G99 will need to be applied for.

Synsynk 5kwh Ecco is looking very good for this plan currently
Battery wise, thinking OTS pylontec or seplos mason eve kit.
look good as a no hassle set up, Im not an electrician, but am confident i could make a battery system if needed/ worth it.

System will have to be agile tarriff 'smart'
Thanks

[Fintray]

Welcome to the forum NB, there are a few on here from Aberdeenshire as well.
Wondering if your PV now on 2 strings is getting to start up voltage of the inverter compared to being on a single string?

Several of us in Aberdeenshire are building battery packs with cells from China so may be able to offer some advice.

My plan is to charge up the additional batteries at the cheap rate to run the house (and heat pump) during the day, this will also have the ability to run the whole house in the event of a power cut.

[nowty]

Welcome NoraBatty.

What is your Solis inverter model number ?

It might be a single MPPT tracker version or limited by operating outside of the lower end of the MPPT voltage range.

[NoraBatty]

Lovely to hear there are Aberdeenshire folk around, and nice to meet you all.
@Fintray, That sounds pretty similar to what we want from the battery. I say we, my oh couldn't give two hoots about any of it.

Inverter is S6-GR1P3K
Mppt voltage range 90-520V

Thanks.

[nowty]

Lovely to hear there are Aberdeenshire folk around, and nice to meet you all.
@Fintray, That sounds pretty similar to what we want from the battery. I say we, my oh couldn't give two hoots about any of it.

Inverter is S6-GR1P3K
Mppt voltage range 90-520V

Thanks.

The start up voltage is 120V so the 3 panel string might not start it up but the 4 panel string certainly should.

[NoraBatty]

Interesting, thank you. That may work out okay as there is room to squeeze a4th on in landscape. Just, which I planned to do.
Also explains why the logger seems to show the north facing ones better performing.
I assumed a lead was not connected properly, but as this happened before we owned them, it was hard to tell unless going on a very steep roof to check.
I can get some 445w panels in the same size. Aiko, or jinko. Worth swapping them out for some extra oomph or not?

Any for or against the sunsyk ecco idea?
Thanks