Hi I have been quoted on a system comprising
16 x 535 watt panels
FoxEss H1 G2 hybrid inverter
FoxESS ep12 plus battery
Questions
Is this a good system.?
Is the inverter a good one. I’ve seen mention of a K series and am assuming that is more recent?
Is there a lot of cost difference between the two and is it worth the difference (assuming that I can have that as the inverter )
Thanks in advance first dipping my toes into the solar power options
That is a good size of system, the H1 G2 is the latest generation of the H series inverter, the H series is a ‘small’ domestic hybrid inverter and has output sizes from 3kw to 6kw with 2 independent strings.
With 16*535 watt panels I would hope you are being quoted for the H1 6.0 (6kw output) which will need G99 approval from your DNO.
The KH inverter is the next size of inverter up, being a large domestic single phase inverter from 7 to 10.5kW output and can support either 3 or 4 strings.
If the 16 panels is the maximum you can fit then the H series will be the best size for you, if there is a chance you can add further panels to your system in the future you might want to consider getting the KH instead which would give you that extra expansion capability, if not stay with the H series - price wise there is only a few hundred pounds between them.
With 16*535 watt panels I would hope you are being quoted for the H1 6.0 (6kw output) which will need G99 approval from your DNO.
The KH inverter is the next size of inverter up, being a large domestic single phase inverter from 7 to 10.5kW output and can support either 3 or 4 strings.
If the 16 panels is the maximum you can fit then the H series will be the best size for you, if there is a chance you can add further panels to your system in the future you might want to consider getting the KH instead which would give you that extra expansion capability, if not stay with the H series - price wise there is only a few hundred pounds between them.
Thanks Dave I could expand at a later date if I put panels on the garage would I need to increase the battery size as well? Currently going to be EP12 plus
The typical progression when people buy solar for the first time is that after 6-12 months they wish they’d added more panels or batteries as they get real world stats of how it works for them.
When the main install goes ahead it’s wise to use the scaffold then to install all the possible panels as the cost to scaffold later may preclude you from adding more panels.
From what you have said adding more panels to the garage (as long as as it’s 4 or more), it would make sense to have a KH 7 with the extra string (MPPT).
The battery size depends very much on your typical usage, ideally you should look at your daily usage and have a battery that is (at least) 120% greater so that if you have a low tariff (such as an EV tariff or eco 7) in the low (no) solar months of December/January you can charge the batteries on the low tariff and run the house completely from them.
This is a slightly complex subject as it depends on whether you have a heat pump, an EV etc.. as to what the best battery capacity will be but ‘the I wish i’d added another battery’ is a common theme and so if you are in doubt it’s best to do that now as the install will be much cheaper to do that now than later - but if you are a very low power user i.e. ~8kwh per day the single battery will be ok.
When the main install goes ahead it’s wise to use the scaffold then to install all the possible panels as the cost to scaffold later may preclude you from adding more panels.
From what you have said adding more panels to the garage (as long as as it’s 4 or more), it would make sense to have a KH 7 with the extra string (MPPT).
The battery size depends very much on your typical usage, ideally you should look at your daily usage and have a battery that is (at least) 120% greater so that if you have a low tariff (such as an EV tariff or eco 7) in the low (no) solar months of December/January you can charge the batteries on the low tariff and run the house completely from them.
This is a slightly complex subject as it depends on whether you have a heat pump, an EV etc.. as to what the best battery capacity will be but ‘the I wish i’d added another battery’ is a common theme and so if you are in doubt it’s best to do that now as the install will be much cheaper to do that now than later - but if you are a very low power user i.e. ~8kwh per day the single battery will be ok.
Thanks very much my annual consumption of electricity is currently around 2490 kWh but my game plan is to sell back to the grid to reduce payback duration and eventually give myself a net income
Just note that the future of flat export tariffs where you get paid a flat xx p kWh might not always be there in the future.
The current ROI calculations are crystal ball stuff, if you fit plenty of panels now, whilst scaffolding is up, that's best.
You may have to think on getting more battery storage added at a later date, depending on what happens to solar export payments in the future.
A bigger battery would help you to save the solar during the day, and dump it during the typical evening peak period, where you can make much more money.
It's a complex call on what to do, a fair few variables.
The current ROI calculations are crystal ball stuff, if you fit plenty of panels now, whilst scaffolding is up, that's best.
You may have to think on getting more battery storage added at a later date, depending on what happens to solar export payments in the future.
A bigger battery would help you to save the solar during the day, and dump it during the typical evening peak period, where you can make much more money.
It's a complex call on what to do, a fair few variables.
Hi Dave so the end setup they have advised is 16 panels (635 W) EP12 plus battery and Fox K series KH7 inverter
Does this seem a sensible specification to cover 2500 electric usage and give a good export back to the grid? I’m hoping to export sufficient to minimise payback period and also cover my gas bill which is in the region of £800 per year
I am thinking of switching to the Octopus supplier is this currently the best supplier still and what is the best tariff to go on
Thank you for all your advice it is very much appreciated
Does this seem a sensible specification to cover 2500 electric usage and give a good export back to the grid? I’m hoping to export sufficient to minimise payback period and also cover my gas bill which is in the region of £800 per year
I am thinking of switching to the Octopus supplier is this currently the best supplier still and what is the best tariff to go on
Thank you for all your advice it is very much appreciated
If this helps, I have KH7 & EP11. Without trying hard, I 'made' just over £1200 last full year with 6.16kWp worth of panels.
With your 10.16kWp, you should be fine to make at least that, and more.
With your 10.16kWp, you should be fine to make at least that, and more.
What energy supplier and tarrif are you with ?
I’d echo what @MB said, that should be a decent sized system for your needs and give you scope in future for expansion.
I would think the best tariff for you would be Octopus Flux but there are also add ons to that with products like Axle Energy where they pay some very impressive export rates when the grid is under duress.
I would think the best tariff for you would be Octopus Flux but there are also add ons to that with products like Axle Energy where they pay some very impressive export rates when the grid is under duress.
Thanks to both of you for your answers. You have been very helpful working my way through the minefield of information 
Octopus Agile tariff, so you sometimes get negative rates. Though in Winter it can get wild if the wind dies down.
The sunny & windy weekends are where you can benefit the most from this.
Flux can be ok, though never used it.
You might be able to sign up to Octopus Go, as I don't think they check for EV... could be wrong?
You can look here for some historical price data.
https://agile.octopushome.net/historical-data
I am on the Fixed outgoing that gives a flat 12p kWh all day/night.
You can combine this with Axle Energy, that pay you £1 kWh when the demand is high in your region, they pay a min of £10 pcm. So you will get £1.12 kWh during these nice demand led events.
I do have a code you can use for a bonus £25 sign up if you are interested.
I just see Dave made a post too, it really does work well with Axle currently, and you can maximise the ROI that you are seeking (whilst the £1 kWh is here)
Here you go, hope you get a nice export limit from DNO!
https://vpp.axle.energy/landing?ref=R-ZIFGMMKO
FWIW: I have just 3.9kW export limit, and have made over the £10 minimum monthly earnings floor.