We seem to use a lot of electricity, about 5200 kWh per annum, compared to the national average. An EV charger accounts for a fair bit I suspect.
My local authority have teamed up with solar providers so as to offer a 'value for money package' to its residents. The proposed system from the supplier, who has done the required survey. is as follows:-
14 x CanadianCS6R 430 watt panels. This may increase by 4 at a future date on a separate roof.
2 x FoxEES EP5 batteries – 9.3 kWh
1 x FoxESS H1&AC 4.6-E inverter. Input power 5980 watts
Understandably they have selected a relatively fixed set of options in order to be able to offer a series of packages that are at a reasonable cost.
So my questions are as much about their proposed package as to what might be a better set-up for the future. The choice of panels may be non-negotiable but the FoxESS kit has many alternatives I suspect.
1. Is the inverter
a) the right model?
b) the right size (given a possible further 4 panels) and if too small how big to go for?
c) are there implications (G99 I think) if I go larger?
d) do all hybrid inverters work with Octopus Agile or Flux?
2. Have they suggested the most appropriate batteries, would EP11 be more appropriate?
3. How big should should the battery storage be? I could add another EP5 to achieve 14 kWh but maybe there is a break even point and that 14 kWh capacity might be overkill.
4. Am I right in thinking that Home Assistant doesn't work on Windows and that I will best set up an alternative micro pc platform, or equivalent.
It's a bit like diving into a raging river and not being really sure which way to land so any advice would be much appreciated.
Like jumping into a raging river
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Dave Foster
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fatfairy wrote: Thu Dec 19, 2024 3:42 pm 1. Is the inverter
a) the right model? - I would suggest getting the H1-6 inverter, there is little value in getting the H1-4.6 the larger 6kW unit will give a bit more PV expansion capability and handle more PV power without clipping, and will be able to meet bigger house loads 6kW vs 4.6kW when running on battery - it’s the same size and in all honesty maybe an extra £100.
b) the right size (given a possible further 4 panels) and if too small how big to go for? - if the array is split into 2 equal sized arrays it would just be big enough to handle the extra panels - but the H1-4.6 can only output 4.6kW on its AC output and so if the batteries are full the array would be clipped - again go with the H1-6.
c) are there implications (G99 I think) if I go larger? If they are quoting the 4.6 you are already on G99 (G98 max is 16A ~ 3680 watts), again go with H1-6 and get G99 for that.
d) do all hybrid inverters work with Octopus Agile or Flux? - yes you can program charge (and discharge slots) to work with Agile and Flux - Fox have an application that works with Agile, but if you want to seriously exploit it I would recommend the home assistant.
2. Have they suggested the most appropriate batteries, would EP11 be more appropriate? - you can approach this from 2 angles - a full cost benefit analysis to work out your daily usage and make sure the saving from batteries (using low tariff meets your demand) or get the biggest batteries you can afford… I’ll be honest i’m more in the second camp, i’ve never heard anyone say I wish I didn’t have that extra battery capacity. And given your annual consumption I would suggest you are undersized (don’t forget you will only get 90% of the rated capacity) the EP11’s would make more sense as they have a higher dc voltage and so will more easily meet the output power of the inverter. In cold temps the batteries can be throttled and having the higher voltage will still allow you to meet your house loads whereas the EP5’s might struggle.
3. How big should should the battery storage be? I could add another EP5 to achieve 14 kWh but maybe there is a break even point and that 14 kWh capacity might be overkill. - I sort of covered that above - you are using at least 14kWh a day now and so if you change anything (like get a heat pump) you will be exposed with the EP5’s. Yes you can install 4 of them but they take wall space to do that and you’ll need a long clear run to mount them. With 2 * EP11’s you’ll have plenty of capacity, you will use less wall space, because of the higher voltage be unlikely to see low temperature affects and you’ll still be able to expand if you need more power later.
4. Am I right in thinking that Home Assistant doesn't work on Windows and that I will best set up an alternative micro pc platform, or equivalent. - Home assistant would work on a windows VM, but think of it more like a mini computer that is on 24/7 taking care of the system (agile charge periods etc.)- all you do is connect to it to view your ‘dashboards’ and energy use, it can send you alerts or notifications straight to your phone and you can connect to it from any browser or install an app on a phone or tablet that works well on those devices..
Most people use things like a raspberry pi with an SSD, or an Intel mini computer - you install home assistant on it, connect it to the inverter and leave it running all the time - you’ll be amazed what it can do, and what you will do with it once you have. There is loads of help and guides written for this.
It's a bit like diving into a raging river and not being really sure which way to land so any advice would be much appreciated.
Just ask any questions you want here - hopefully it’s not raging as much and we can make it more like a stream….
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Dave Foster
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- Joined: Thu Oct 13, 2022 7:21 pm
No problem, i'm sure there will be - when I first ventured into Solar even with a background in engineering I still didn't know what I needed to know - that's why Will created these forums to provide a powerful resource for people starting out.fatfairy wrote: Thu Dec 19, 2024 10:17 pm Thank you Dave for such a comprehensive answer. Being rather old I am going to need a little while to digest it all and then I suspect there may be some additional clarification so again thanks for the offer of further support.
Hello again. I've now had my 'final' quotation and interestingly enough they have moved towards much of what you have suggested. They have replaced the two EP5 with one EP11 (10.36 kWh) and upped the inverter to the 5.0 kWh model.
So I asked what the extra cost would be for the 6.0 kWh version and was advised that it was the same price. However, the contact handler then said, quoting someone she had gone off to speak to about the cost, that it was possible that there would be 'less generation' due to the fact that I only had 14 panels. If it was sixteen panels then the 6.0 kWh would be what they would suggest but for 14 panels they recommended the 5.0 kWh model. The explanation rather baffled me so I'm wondering if this 'less generation' makes any sense. Incidentally it is possible, but not probable, that extra panels could be installed in a year or two.
I also asked how much a second battery would be and got a price of £2731. Oddly the first battery costs £3267 and I'm told this was the negotiated price between the Council and Solar Together. I guess the uplift is the installation and wiring of the stuff in the garage. Got to decide if I can find the extra £2731, persuade me it makes sense to do it!
Downside of having a roof able to take 14 panels is that the scaffolding costs jump up due to width of the house, some you win some you lose.
Thanks again for help on this, hopefully I'll at least break even on the capital cost in my lifetime.
Best wishes and I hope all you folk supporting the forum have a great festive season.
Frank
So I asked what the extra cost would be for the 6.0 kWh version and was advised that it was the same price. However, the contact handler then said, quoting someone she had gone off to speak to about the cost, that it was possible that there would be 'less generation' due to the fact that I only had 14 panels. If it was sixteen panels then the 6.0 kWh would be what they would suggest but for 14 panels they recommended the 5.0 kWh model. The explanation rather baffled me so I'm wondering if this 'less generation' makes any sense. Incidentally it is possible, but not probable, that extra panels could be installed in a year or two.
I also asked how much a second battery would be and got a price of £2731. Oddly the first battery costs £3267 and I'm told this was the negotiated price between the Council and Solar Together. I guess the uplift is the installation and wiring of the stuff in the garage. Got to decide if I can find the extra £2731, persuade me it makes sense to do it!
Downside of having a roof able to take 14 panels is that the scaffolding costs jump up due to width of the house, some you win some you lose.
Thanks again for help on this, hopefully I'll at least break even on the capital cost in my lifetime.
Best wishes and I hope all you folk supporting the forum have a great festive season.
Frank
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Dave Foster
- Posts: 1393
- Joined: Thu Oct 13, 2022 7:21 pm
There’s no substantial loss in having a 6kW inverter over a 5kW inverter they are fundamentally the same thing with a handful of additional components inside.
14 panels will work effectively on either with the same output but if you are fitting extra panels the 6kW would be better for you.
Having the 6kW when running on battery would also allow you to have up to 6kW of house load met from the batteries without requiring any grid to ‘top it up’.
You may not often have a house load of 6kW, a kettle and the main oven would likely do it but when that happens all the power would be sourced from the battery without grid import, with the 5kW you would need to top up with 1kW from the grid.
So I would say that there was nothing to lose and something to benefit in getting the 6kW, but either way the 5kW would serve you well.
On the battery i’m glad they’ve gone EP11 it is far more capable of meeting the loads across all temperature ranges, and the extra cost as you say will be installation (the battery is very heavy ~100kg and must be mounted to a wall) plus there will be cabling and also a junction box that is needed to add additional batteries.
It’s a difficult call to add the extra battery from what you have said from your annual usage I think you would make use of it but the payback period could be 10 years+ and given the current market conditions (lack of base load, retiring nuclear, a huge backlog of generator grid connections etc..) I suspect in that timeframe energy costs will only be going up.
With a single EP11 when using a low overnight tariff in the winter months you will be close to covering all your daily home use anyway, so i’ll leave you with that dilemma - only you will be able to work that through.
The one thing I will say is that at £2,731 installed you will likely never get a better price than that unless you do a diy install yourself and with a 100kg battery pack it’s better left to someone with the equipment to handle that weight.
All the best
14 panels will work effectively on either with the same output but if you are fitting extra panels the 6kW would be better for you.
Having the 6kW when running on battery would also allow you to have up to 6kW of house load met from the batteries without requiring any grid to ‘top it up’.
You may not often have a house load of 6kW, a kettle and the main oven would likely do it but when that happens all the power would be sourced from the battery without grid import, with the 5kW you would need to top up with 1kW from the grid.
So I would say that there was nothing to lose and something to benefit in getting the 6kW, but either way the 5kW would serve you well.
On the battery i’m glad they’ve gone EP11 it is far more capable of meeting the loads across all temperature ranges, and the extra cost as you say will be installation (the battery is very heavy ~100kg and must be mounted to a wall) plus there will be cabling and also a junction box that is needed to add additional batteries.
It’s a difficult call to add the extra battery from what you have said from your annual usage I think you would make use of it but the payback period could be 10 years+ and given the current market conditions (lack of base load, retiring nuclear, a huge backlog of generator grid connections etc..) I suspect in that timeframe energy costs will only be going up.
With a single EP11 when using a low overnight tariff in the winter months you will be close to covering all your daily home use anyway, so i’ll leave you with that dilemma - only you will be able to work that through.
The one thing I will say is that at £2,731 installed you will likely never get a better price than that unless you do a diy install yourself and with a 100kg battery pack it’s better left to someone with the equipment to handle that weight.
All the best