New here, component question

Hi there all, I'm new here! (sorry for the long post)

I have 0 experience in DIY electronics or solar power, only basic installing new sockets & lights1

I would like to go fully off-grid eventually, but I am not looking to be silly with money - I think a 10% average return over 3-5 years would be reasonable, but otherwise not really feasible, so I am looking to install a system in stages (ensuring parts are suitable for future improvements)

Since doing the entirety in one go is not really feasible, and since I live in the UK with Octopus Energy, the first logical step seems to be to utilise the £0.075/kWh "Intelligent" tarriff (night rate) which lasts 6 hours to charge a battery, then utilise the battery during the day.

For reference, my house uses roughly 25 kWh per day.

Fogstar appear to offer a 30 kWh solution

Considering 6 hours overnight can be grid-tied on the night tarriff, 30kWh seems to be enough to cover the daily usage plus reserve.

My first thought was that the fogstar battery seems reasonable, all-in-one system with BMS built in...
Looking on alibaba though, this could potentially built for <£3000 so I am debating whether the extra £3000 is worth the time and chance of screwing up

Lets assume using the fogstar battery for now, which I think would be a negative yield over 5 years

UK mains single phase is 240V 100A according to the fuse

According to the battery on fogstar, the max discharge rate is 48V 600A, so converted this would be 240V ~120A (minus conversion losses)

I believe the 1C means it can charge at the maximum discharge rate? If we have 6 hours in which to charge the battery, it could therefore charge at a mains rate of 240V 21A (plus conversion losses) so we don't need to get close to that rate for charging.

I reckon that I spend £200/month although this varies quite a bit. Using only the standing charge of ~£0.59/day and the night rate of £0.075/kWh for 30kW, that would work out at £85/month + EV charging, maybe £25/month so £110/month meaning a reduction of £90/month or £5400 over 5 years, now this is not factoring in potential rises in price (which seem likely) or the removal of this tarriff - at which point I would be looking to entirely break with the grid.

Key points:

• Grid-to-battery instantaneous changeover i.e. would not affect a computer
• No interest in feeding back to grid
• Over a 24 hour period; battery must charge in 6 hours & cover 25kWh for the rest of the period
• Components should be future-proof against adding a high power solar (25kW) & wind system (10kW) for going off-grid eventually (more batteries in future)

I have a few questions which I would really appreciate your support with:

1) Aside from the fogstar battery, which includes a BMS, what other components would be needed to tie this into my home system with instant grid-switch? (I do not want to feedback to the grid)

2) Does this look feasible?

3) If I was to go with the alibaba batteries & the same BMS that fogstar uses, are there any other considerations than wires, busbars & a case that would be required?

4) In future, what additional components would be needed to go completely off-grid (aside from panels, turbines, more batteries & their fixings/mountings/cables)? (I do not want to feedback, excess will be burned off more efficiently)

Watt am I doing? said:

Hi there all, I'm new here! (sorry for the long post)

I have 0 experience in DIY electronics or solar power, only basic installing new sockets & lights1

I would like to go fully off-grid eventually, but I am not looking to be silly with money - I think a 10% average return over 3-5 years would be reasonable, but otherwise not really feasible, so I am looking to install a system in stages (ensuring parts are suitable for future improvements)

Since doing the entirety in one go is not really feasible, and since I live in the UK with Octopus Energy, the first logical step seems to be to utilise the £0.075/kWh "Intelligent" tarriff (night rate) which lasts 6 hours to charge a battery, then utilise the battery during the day.

For reference, my house uses roughly 25 kWh per day.

Fogstar appear to offer a 30 kWh solution

Fogstar Energy 30kWh 48V Rack Battery Bundle

30kWh 48v Rack Battery Lithium (LiFePO4) heating, pre-loaded inverter protocols, LCD touch screen, Grade A EVE Cells, a DC Rated Breaker and an 8 year warranty.

www.fogstar.co.uk

Considering 6 hours overnight can be grid-tied on the night tarriff, 30kWh seems to be enough to cover the daily usage plus reserve.

My first thought was that the fogstar battery seems reasonable, all-in-one system with BMS built in...
Looking on alibaba though, this could potentially built for <£3000 so I am debating whether the extra £3000 is worth the time and chance of screwing up

Eve Lf280k 8000cycles 3.2v Lithium Cells Lifepo4 320ah Eve 280ah Grade A 32v Rechargeable Battery Lifepo4 Batteries - Buy Eve 280ah Lifepo4 Lfp 32v Cells Battery lifepo4 320ah Battery Trade lifepo4 100ah 32v Product on Alibaba.com

Eve Lf280k 8000cycles 3.2v Lithium Cells Lifepo4 320ah Eve 280ah Grade A 32v Rechargeable Battery Lifepo4 Batteries - Buy Eve 280ah Lifepo4 Lfp 32v Cells Battery lifepo4 320ah Battery Trade lifepo4 100ah 32v Product on Alibaba.com

www.alibaba.com

Lets assume using the fogstar battery for now, which I think would be a negative yield over 5 years

UK mains single phase is 240V 100A according to the fuse

According to the battery on fogstar, the max discharge rate is 48V 600A, so converted this would be 240V ~120A (minus conversion losses)

I believe the 1C means it can charge at the maximum discharge rate? If we have 6 hours in which to charge the battery, it could therefore charge at a mains rate of 240V 21A (plus conversion losses) so we don't need to get close to that rate for charging.

I reckon that I spend £200/month although this varies quite a bit. Using only the standing charge of ~£0.59/day and the night rate of £0.075/kWh for 30kW, that would work out at £85/month + EV charging, maybe £25/month so £110/month meaning a reduction of £90/month or £5400 over 5 years, now this is not factoring in potential rises in price (which seem likely) or the removal of this tarriff - at which point I would be looking to entirely break with the grid.

Key points:

• Grid-to-battery instantaneous changeover i.e. would not affect a computer
• No interest in feeding back to grid
• Over a 24 hour period; battery must charge in 6 hours & cover 25kWh for the rest of the period
• Components should be future-proof against adding a high power solar (25kW) & wind system (10kW) for going off-grid eventually (more batteries in future)

Click to expand...

Hello and welcome to the forums.

I'm sure others will chime in and give you better answers but I'll have a go at it for the time being.

Watt am I doing? said:

I have a few questions which I would really appreciate your support with:

1) Aside from the fogstar battery, which includes a BMS, what other components would be needed to tie this into my home system with instant grid-switch? (I do not want to feedback to the grid)

Click to expand...

Best bet is get a AiO solar inverter if your intending to wire it yourself.
This obviously allows you to connect solar at a later date but for now will happily charge your batteries at night and convert your batteries to power during the day but you will need to know maximum current draw of your home at any one time to select your wattage. There's a few that also can feed back to the grid if you chose to do so at a later date but then it would likely have to be inspected. I'll leave suggestions of model to others once you know maximum current draw

Watt am I doing? said:

2) Does this look feasible?

Click to expand...

Yes plenty of people do it, many on the forum like have done or do currently.

Watt am I doing? said:

3) If I was to go with the alibaba batteries & the same BMS that fogstar uses, are there any other considerations than wires, busbars & a case that would be required?

Click to expand...

Don't, if your not confident in your knowledge and haven't got the right tools your walking into a literal minefield not to mention most batteries sold on marketplaces are generally used prior in older EV so the cycle life (how many charges within lifetime)will be considerably lower than your current choice.

Watt am I doing? said:

4) In future, what additional components would be needed to go completely off-grid (aside from panels, turbines, more batteries & their fixings/mountings/cables)? (I do not want to feedback, excess will be burned off more efficiently)

Click to expand...

Going off the way I've answered above you would just want panels. As you delve deeper you will find out that going off grid means you actually can end up using more power during the day to make the most of your panel output if your not feeding back to the grid this is because any excess power the panels produce you don't use is lost as heat through the panels and will shorten their life.

Check out threads on the forums here and there's plenty to read in the resources section

Good luck and welcome once again.

Oh and ps. 35kw in solar and wind is likely insane for your usage of 30kwh a day you would likely produce that with just 15kw even in sunny old blighty though I'm not 100% correct on this https://www.suncalc.org/ and https://forecast.solar/ will give you a better idea

ThaiTaffy said:

Hello and welcome to the forums.

Click to expand...

Thanks a lot! And I really appreciate the advice

I think regards the max current draw, it would be safest to assume the max would be what the grid could supply in the usual way (240V 100A) although it is likely to never exceed 60% of that

ThaiTaffy said:

Don't, if your not confident in your knowledge and haven't got the right tools your walking into a literal minefield not to mention most batteries sold on marketplaces are generally used prior in older EV so the cycle life (how many charges within lifetime)will be considerably lower than your current choice.

Click to expand...

This is kind of what I was thinking... Sourcing quality at a good price is likely to be the hardest part, and without the proper tools to extensively test the batteries, I can see how that would be problematic.

ThaiTaffy said:

Oh and ps. 35kw in solar and wind is likely insane for your usage of 30kwh a day

Click to expand...

Well, what I was thinking regarding this is that; my usage is a bit more due to EV (maybe 50kw), but EV can charge from mains on the night rate, so no need to add that to the battery...

My logic was that:
On the shortest day of the year (approx. 7 hours in the UK), the weather is likely to be poor since it is during winter, so roughly assuming the ambient light provides 20% of full sunlight for the full day, that equates to 1.4 hours of full sunlight, during which time the batteries would worst-case need to charge from 0% to 100% (or at a rate of ~21.5kw) accounting for losses and safety factor, 25kw.

Wind would likely come after panels as an extra safety margin, just in case...

I would plan to "burn off" extra power in a massive heated pond until I can make better use of it (excess power isn't a bad thing to have!) - could dump it into a swimming pool or indoor grow-light farm (no not THAT plant), etc, if it is something profitable it would be worth buying more batteries to dump it into to stabilise the flow

Watt am I doing? said:

Thanks a lot! And I really appreciate the advice

I think regards the max current draw, it would be safest to assume the max would be what the grid could supply in the usual way (240V 100A) although it is likely to never exceed 60% of that


This is kind of what I was thinking... Sourcing quality at a good price is likely to be the hardest part, and without the proper tools to extensively test the batteries, I can see how that would be problematic.


Well, what I was thinking regarding this is that; my usage is a bit more due to EV (maybe 50kw), but EV can charge from mains on the night rate, so no need to add that to the battery...

My logic was that:
On the shortest day of the year (approx. 7 hours in the UK), the weather is likely to be poor since it is during winter, so roughly assuming the ambient light provides 20% of full sunlight for the full day, that equates to 1.4 hours of full sunlight, during which time the batteries would worst-case need to charge from 0% to 100% (or at a rate of ~21.5kw) accounting for losses and safety factor, 25kw.

Wind would likely come after panels as an extra safety margin, just in case...

I would plan to "burn off" extra power in a massive heated pond until I can make better use of it (excess power isn't a bad thing to have!) - could dump it into a swimming pool or indoor grow-light farm (no not THAT plant), etc, if it is something profitable it would be worth buying more batteries to dump it into to stabilise the flow

Click to expand...

No expert here but personally especially getting started and the fact you will likely want to charge ev,s, pools, ponds and so on at a later date I would look at the 10kw(41amp) range to begin with, the idea you could add more in parallel working as slaves and anything above 10k starts to get in the multiple phase domain. I only really know a little about AiO but maybe others can suggest something more modular.

From looking online at solar stores in the UK (unless someone can suggest a good distributor)?I really wouldn't buy anything as it's mainly the same Chinese stuff I have available and I'm guessing you would prefer something with more customer support(alot of Chinese inverters are great but support is mainly where they're lacking).

I'm currently looking at running the whole farm off-grid and we seem to average 22kw a day which due to the weather I can likely cover with a 5kw system(if not I've also selected a system I can parallel and add another inverter) but we only use a maximum peak draw of 18amps and that's all the essentials, 2 AC units and the kettle.

Apart from your car which is obviously the major peak draw you have and the reason for that 100amp supply, you should take a look at things around the house which are essential and would definitely be on your first battery and inverter.
I might be pointing you down another rabbit hole but I use home assistant to monitor my energy usage, control and monitor my solar, aswell as pretty much everything else in the house it's likely able to control your EV charging and also the main thing especially for off grid solar and switching on loads without having to do it manually. Also I can monitor my home here when I visit family in Wales.

First - Does your power bill for the last 12 months include a usage stat for days or time of day? If you have those you can get your daily kW usage from it.


Another way to find out your max usage -


The other way to do it that is less accurate go around to all your direct wired appliances and such and collect the information on the model plates - it should list amps to run, and on things like the AC or well pump it should list the start current as well.

If an item has a large motor but doesn't list start current you can assume 3 to 5 times the run current. You can also use the clamp meter from above if it has an 'inrush' setting or a max hold button.

For smaller items you can use a UK equivalent of a kill-o-watt meter like the one below

For it you just set your power price and plug the device in and turn it on to get the wattage

Add everything up and it will give you an idea of your true wattage used.



Get a clamp meter that will read both AC and DC current - you will use it doing solar too so it isn't a 1 and done type tool

Hook it around one wire that feeds your main panel - turn on ever ything in the house - it will tell you how many amps you are using.
NOTE - do this outside the main panel if possible to do safely - If not possible take the cover off the panel and see if you can hook it to the main feed wire.

@Watt am I doing? I looked around the forums looking for UK suppliers and came across this thread @SeaGal (sorry to tag you but you likely have alot more knowledge than me concerning the uk) made a post a few posts down that should give you some better answers as well as some supplier names I did see one supplier with some larger sunsynk inverters that would be suitable.

ThaiTaffy said:

you should take a look at things around the house which are essential and would definitely be on your first battery and inverter.

Click to expand...

I think in order to make it financially viable, everything except for the car would need to be on battery power - could possibly offset some washing/drying to the off-peak hours though, but definitely fully electric cooker + oven & electric shower would need to be on battery power so pretty high draw

robbob2112 said:

Does your power bill for the last 12 months include a usage stat for days or time of day? If you have those you can get your daily kW usage from it.

Click to expand...

Hi there, I do have some level of visibility, I can see half hourly draws, daily, weekly, monthly, but the data is somewhat skewed by both the EV and the tarriff that I am on (rates fluctuate and can go negative at which point everything is turned on!)

Normal days appear to be around 25kw on average but with the EV charging it can reach 60kw days or negative rates can skew it up to 70kw

Unfortunately I can't easily filter the data, or account for price variability (if we had the night rate, we would more accurately schedule regular high usage)

robbob2112 said:

Get a clamp meter that will read both AC and DC current - you will use it doing solar too so it isn't a 1 and done type tool

Click to expand...

Good idea, I'll get one of these

ThaiTaffy said:

made a post a few posts down that should give you some better answers as well as some supplier names I did see one supplier with some larger sunsynk inverters that would be suitable.

Click to expand...

Thanks, I'll take a look at this!

I have been looking into doing this kind of thing for a good couple of years now, but it isn't really something you can just "give it a try" with, you really have to have a solid plan!

Watt am I doing? said:

I think in order to make it financially viable, everything except for the car would need to be on battery power - could possibly offset some washing/drying to the off-peak hours though, but definitely fully electric cooker + oven & electric shower would need to be on battery power so pretty high draw

Click to expand...

What I mean is unless you can source a decent 15kw+ inverter you will have to split the loads between multiple smaller inverters so planning that would be checking what items are essential IE cooker,lights,sockets on first inverter shower, AC units etc on second also if your aiming for solar later you should look at what loads would be viable to turn on when you need to dump power.
On our little off-grid inverter here when the batteries are fully charged we have alot of fans that are automatically turned on one by one as the PV output increases, on the larger system AC units will do the same. I know your only planning battery at the moment but best to think about this now otherwise you will have to rewire distribution boards again when you take that step to solar.

ThaiTaffy said:

What I mean is unless you can source a decent 15kw+ inverter you will have to split the loads

Click to expand...

Out of curiousity, and my house is on single phase power, is there any reason why I couldn't use a 3 phase inverter? (but only connect a single phase to the grid, and a single phase to battery) with the possibility to then connect 2 other phases to more batteries & more solar?
It would be more load to shed when the batteries are full sure, and balancing it would be more difficult, but in the long-term it would work out better because in theory my EV can charge on 3 phase at maximum speed to make the most of short periods of good solar power, workshop 3 phase would be nice too

3 phase MPPT inverters seem to be readily available, but I am not sure how they work with a battery, it is all very confusing! MPPT inverters seem to be best for solar though, so if I could pre-install the right thing when doing the battery, it would save money down the road with solar

Watt am I doing? said:

Out of curiousity, and my house is on single phase power, is there any reason why I couldn't use a 3 phase inverter? (but only connect a single phase to the grid, and a single phase to battery) with the possibility to then connect 2 other phases to more batteries & more solar?
It would be more load to shed when the batteries are full sure, and balancing it would be more difficult, but in the long-term it would work out better because in theory my EV can charge on 3 phase at maximum speed to make the most of short periods of good solar power, workshop 3 phase would be nice too

Solis 50.0kW 3 Phase Quad MPPT with DC Select solar The solar professionals Select Solar - The solar power professionals

Solis 50.0kW 3 Phase Quad MPPT with DC`

www.selectsolar.co.uk

3 phase MPPT inverters seem to be readily available, but I am not sure how they work with a battery, it is all very confusing! MPPT inverters seem to be best for solar though, so if I could pre-install the right thing when doing the battery, it would save money down the road with solar

Click to expand...

I might be wrong here but 3 phase in the UK would work differently to how many forum members use it in the US, to get a single phase 240v you have to link phases then buck that down to the desired 240 aswell as balance each phase. It's not the same as pulling 120v single phase from a 380v 3phase as they do in the US, your likely much better off using a transformer in the UK.

I'm in the UK. I have a 3kW Solis Hybrid inverter with 3kW of PV and 4.8kWh of Pylontech batteries. I use Octopus Agile. I don't have an EV.

The Solis is a grid-tied inverter which means it connects to your existing feed from the grid. The main AC connection is used as input for charging batteries from grid (timed charge can be set), and output to drive your load and export to grid. There is a second AC Backup output which can be used to drive a separate Critical Loads circuit that will remain up if the grid fails.

I'm not specifically recommending the Solis because I have no experience with other inverters so can't say how it ranks in comparison. But the install is fairly simple and it seems to work for me. ROI is going to be about 7 years and that's paying an installer to do all the work (complete with ridiculous mark up on batteries!).

In summer my bills are usually zero or lower. In winter they are about half what they would have been with no inverter and using a standard rate tariff.

The Agile tariff varies a lot, and sometimes the prices can be high, so you have to take the rough with the smooth and decide which days to charge things up and do all your laundry. But you do get great days like Christmas last year when the prices dropped to zero or lower for a few days. Christmas day I used 41kWh from grid at a cost of -42p, which when you add my daily standing charge of 42p, comes to 0p total

[edit to add] The new Solis S6 range is supposed to support connecting multiple hybrid inverters in parallel. With the S5 you can only have one hybrid, but many AC Coupled (without batteries).

ThaiTaffy said:

I looked around the forums looking for UK suppliers and came across this thread @SeaGal (sorry to tag you but you likely have alot more knowledge than me concerning the uk)

Click to expand...

for the tagging, but you didn't include the actual thread - I've probably posted several on this subject!

Anyway... all good points above. We're also in UK and charge our 14.3kWh battery overnight (economy 7) in Winter to supplement solar production - that has eliminated all peak rate electricity usage for the last two years

Watt am I doing? said:

3 phase MPPT inverters seem to be readily available, but I am not sure how they work with a battery, it is all very confusing!

Click to expand...

The product you linked to is not a hybrid inverter. It has no battery capability.

Watt am I doing? said:

On the shortest day of the year (approx. 7 hours in the UK), the weather is likely to be poor since it is during winter, so roughly assuming the ambient light provides 20% of full sunlight for the full day, that equates to 1.4 hours of full sunlight, during which time the batteries would worst-case need to charge from 0% to 100% (or at a rate of ~21.5kw) accounting for losses and safety factor, 25kw.

Click to expand...

IMHO, without great expense it will be difficult to be self sufficient in UK in Dec and Jan. ROI would be unachievable. For comparison purposes, our lowest yield in Winter with 6.6kWp panels was about 0.7kWh. Rainy Winter days will rarely get more than 1.4kWh. So plan for that top up overnight from cheap grid and aim for 80% solar production that can then get you some reasonable ROI. Our is going to be about 4 years, but that with a 100% DIY build.

One comment - on ROI
When you have a battery system, that is quite costly, but will (likely) last 10-20 years, it is a mistake (from an accounting point of view) to consider it's value to be zero at five years.

On Winter production - low cost overnight rates are my salvation too!

SeaGal said:

for the tagging, but you didn't include the actual thread - I've probably posted several on this subject!

Click to expand...

I distinctly remember copying the thread to my clipboard but sadly I'm an idiot and must not have posted it sorry

SeaGal said:

IMHO, without great expense it will be difficult to be self sufficient in UK in Dec and Jan. ROI would be unachievable. For comparison purposes, our lowest yield in Winter with 6.6kWp panels was about 0.7kWh. Rainy Winter days will rarely get more than 1.4kWh. So plan for that top up overnight from cheap grid and aim for 80% solar production that can then get you some reasonable ROI. Our is going to be about 4 years, but that with a 100% DIY build.

Click to expand...

Ouch it's overcast and miserable here I would have put it on par with Wales but we still seem to get around 2kwh per day off 760w of panels.

I'm sold on getting a system to power the whole house and be self sufficient while offloading any excess back to the grid. Though electricity and solar equipment is slightly cheaper and no shipping costs I've estimated our ROI to be at the 4 year mark also.

OffGridForGood said:

One comment - on ROI
When you have a battery system, that is quite costly, but will (likely) last 10-20 years, it is a mistake (from an accounting point of view) to consider it's value to be zero at five years.

On Winter production - low cost overnight rates are my salvation too!

Click to expand...

Not sure what you mean by this, unless your saying once the roi hits equilibrium the batteries are starting to effectively increase value.

Anyway back to OP I'm still in belief that your better off looking for something AiO around the 10kw mark that can be paralleled and split your most used circuits up, put priority on that with your battery then once you decide to actually get panels you can look at another AiO to service the other circuits. Depending on how it's wired anything excess solar wise can be dumped into your EV when it's home during the day.

Another suggestion would be buy either a raspberry pi or small thin client pc install home assistant os and buy some shelly pm energy monitors this way you can track your actual energy consumption in 10s or so intervals and know exactly what your max current draw is and how many kWh your actually using on specific circuits it would also be a simpler way to tell when your battery should charge and when you get solar allow you to dump excess power into the car.

rpdom said:

The Agile tariff varies a lot, and sometimes the prices can be high

Click to expand...

I am on Agile at the moment since I don't have a battery system

yet, and it is a bit of a rollercoaster. We aren't making the best use of it offsetting major usage aside from the EV charging, but on average, I reckon 7.5p fixed would be better for the EV after using Agile for a month (not a lot of data in only 1 month though)

SeaGal said:

IMHO, without great expense it will be difficult to be self sufficient in UK in Dec and Jan. ROI would be unachievable.

Click to expand...

To be honest, this is why I was looking to have massively more solar than is needed - for those few miserable days that just don't get enough light
I do live in quite a windy area, so there is definitely potential for a turbine, but for ROI it would have to be totally DIY made, commerical ones are just too expensive.

The grid is fine for cheap rates & battery power, but when you rate is cheap enough like the 7.5p Octopus overnight rate, you really hit diminishing returns on ROI and the standing charge starts to become more significant

SeaGal said:

The product you linked to is not a hybrid inverter. It has no battery capability.

Click to expand...

Definitely need to dig deeper with research, trying to go from 0 to 100 knowledge before actually seeing or working with any of these electrical devices is a big challenge in itself!

OffGridForGood said:

it is a mistake (from an accounting point of view) to consider it's value to be zero at five years.

Click to expand...

This is absolutely true, not only will it likely increase the value of the property, but it will continue to provide effectively pure profit beyond the initial payback period
It is a big upfront investment that could otherwise be invested at ~7% in a bank which would provide significant returns over a 5 year period and would compound into a nice stack of cash over that time, so I feel like 5 years is a nice tangible period (I am fairly young, can't be thinking too many years ahead yet!), and put like that, everything over that is then pure profit!

ThaiTaffy said:

I'm still in belief that your better off looking for something AiO around the 10kw mark that can be paralleled and split your most used circuits up

Click to expand...

Given they can parallel and buy more when needed, it sounds like a pretty good idea to be honest - I think most high draw utilities are on different ringmains anyway so I guess that would make it easier to split (i.e. cooker has it's own, showers have their own)

ThaiTaffy said:

I distinctly remember copying the thread to my clipboard but sadly I'm an idiot and must not have posted it sorry

Click to expand...

If it was about suppliers, maybe this posting...

If it was about DIY in UK, maybe this one...

If it was about UK Winter production, maybe this one...

Watt am I doing? said:

To be honest, this is why I was looking to have massively more solar than is needed - for those few miserable days that just don't get enough light

Click to expand...

If you have the space and planning permission, panels are so cheap at the moment.

We can divert excess production to hot water tank and on sunny days I can wash more (clothes that is, not me )!

I suspect the issue you will need to look into and manage the most is your maximum instantaneous power requirement - especially the electric showers which draw a lot.

Watt am I doing? said:

I am on Agile at the moment since I don't have a battery system

yet, and it is a bit of a rollercoaster. We aren't making the best use of it offsetting major usage aside from the EV charging, but on average, I reckon 7.5p fixed would be better for the EV after using Agile for a month (not a lot of data in only 1 month though)

Click to expand...

Home assistant with power meters would likely give you a better understanding of your usage and there might also be a way of adding the agile tariffs to show you when to use certain circuits which could be set up automatically to say charge the EV when the tariff is at its lowest.

Watt am I doing? said:

To be honest, this is why I was looking to have massively more solar than is needed - for those few miserable days that just don't get enough light
I do live in quite a windy area, so there is definitely potential for a turbine, but for ROI it would have to be totally DIY made, commerical ones are just too expensive.

Click to expand...

Few issues here 1st being the type of wind does it sweep your property or is it turbulent, turbulent wind doesn't really mix well with wind power the other issue is construction, for a decent turbine the civil engineering involved can be massive.

Watt am I doing? said:

The grid is fine for cheap rates & battery power, but when you rate is cheap enough like the 7.5p Octopus overnight rate, you really hit diminishing returns on ROI and the standing charge starts to become more significant

Click to expand...

You could likely still look at some form of on-grid/off-grid hybrid system like the sunsynk I mentioned earlier it's possible to DIY it and then have it inspected/tested after the fact then it's just a matter of a few settings to start exporting power.

Watt am I doing? said:

Definitely need to dig deeper with research, trying to go from 0 to 100 knowledge before actually seeing or working with any of these electrical devices is a big challenge in itself!

Click to expand...

Sunsynk,deye,lvtopsun and maybe others are all the same unit search for them here in the forum and it should give you a better understanding.

Watt am I doing? said:

Given they can parallel and buy more when needed, it sounds like a pretty good idea to be honest - I think most high draw utilities are on different ringmains anyway so I guess that would make it easier to split (i.e. cooker has it's own, showers have their own)

Click to expand...

Yep this can all be split but without working out how to split them your just playing guessing games, that's the main reason for my suggestion of home assistant if you have an old pc or even run some form of pc 24/7 you can add a virtual machine or docker and implement it then it's just a matter of adding a few power monitoring WiFi devices this will store the data as default for a year and give you graphs and visual representation of your usage so you can plan accordingly.

SeaGal said:

If it was about suppliers, maybe this posting...

Click to expand...

None of the above. Though likely better information in these

SeaGal said:

If you have the space and planning permission, panels are so cheap at the moment.

Click to expand...

One thing I don't miss living here is permission for anything.

SeaGal said:

I suspect the issue you will need to look into and manage the most is your maximum instantaneous power requirement - especially the electric showers which draw a lot.

Click to expand...

Yes OP a power shower depending on model might require 10+KW so this and the oven your best looking at the rating plates and seeing exactly how much power they require, they could in theory ruin your whole plan but then there's also the possibility of powering them either independently via a standalone inverter or just leaving them to be powered by the grid.

SeaGal said:

and planning permission

Click to expand...

ThaiTaffy said:

One thing I don't miss living here is permission for anything.

Click to expand...

Well that is a potential issue when it comes to doing solar finally, but if it proves too much of an issue, then I'd like to see them try to stop me building a fence, made from bifacial panels. I have plenty of space though, so that is a plus!

I'll spend some time setting up the Raspberry PI & get some monitoring equipment for now, and spend more time browsing your recommended threads! Thanks a lot

Watt am I doing? said:

Well that is a potential issue when it comes to doing solar finally, but if it proves too much of an issue, then I'd like to see them try to stop me building a fence, made from bifacial panels. I have plenty of space though, so that is a plus!

I'll spend some time setting up the Raspberry PI & get some monitoring equipment for now, and spend more time browsing your recommended threads! Thanks a lot

Click to expand...

The pi would need some form of powered external drive, SD cards tend to die doing any form of data logging and usb powered drives tend to corrupt after a few months because the pi can't produce stable power. Some form of drive dock with its own dedicated wall warts works best.

Watt am I doing? said:

I do live in quite a windy area, so there is definitely potential for a turbine, but for ROI it would have to be totally DIY made, commerical ones are just too expensive.

Click to expand...

Small wind turbines seem to be just not worth it, from all the examples I've seen.

ThaiTaffy said:

The pi would need some form of powered external drive, SD cards tend to die doing any form of data logging and usb powered drives tend to corrupt after a few months because the pi can't produce stable power. Some form of drive dock with its own dedicated wall warts works best.

Click to expand...

I've been happily running various USB drives for years now. I've only had a couple fail in that time. One was just old age (HDD), the other was cheap junk (SSD). I've had no problems with the USB power from any Pi.

rpdom said:

I've been happily running various USB drives for years now. I've only had a couple fail in that time. One was just old age (HDD), the other was cheap junk (SSD). I've had no problems with the USB power from any Pi.

Click to expand...

With large SQL databases? Just type "usb hard drive corrupted on pi" into Google you will find out that your case is rare and usb powered hard drives crapping out is the norm.

I converted my Pi to use a spinning drive as a slice to store an active database on. Before that I was burning through a card every few months.

So boots the SD card, then immediately mounts and boots the slices on the spinny drive to run.

To find out how long ago that was.... lookup 'pidrive' by western digital and see when it was discontinued. But the concept is the same with modern hardware

robbob2112 said:

I converted my Pi to use a spinning drive as a slice to store an active database on. Before that I was burning through a card every few months.

So boots the SD card, then immediately mounts and boots the slices on the spinny drive to run.

To find out how long ago that was.... lookup 'pidrive' by western digital and see when it was discontinued. But the concept is the same with modern hardware

Click to expand...

That has a dedicated wall wart no? Guess it would have to as SSDs fail on usb power, spinning drives have no hope. I have a pile of pi's here that got replaced by a single commercial server, I keep thinking of novel uses for them like a robotic lawnmower but I'm yet to actually do anything with them.

ThaiTaffy said:

That has a dedicated wall wart no? Guess it would have to as SSDs fail on usb power, spinning drives have no hope. I have a pile of pi's here that got replaced by a single commercial server, I keep thinking of novel uses for them like a robotic lawnmower but I'm yet to actually do anything with them.

Click to expand...

Old RPi 2b, and it does use just a small wall wart. The PiDrive was manufactured as a dedicated 2.5in USB drive that was low power enough it run off nothing but around .5 amps.

If I had to replace it today I would get the sata interfaced pi and add a ups to the expansion pins. I think it is the banana pi or one of those that has a sata chip