100A fuse upgrade: meter to consumer unit?

[ProDave]

Interesting thing about these tariffs is it makes having a battery system a viable option even for those people without solar as you can cover the expensive period by timeshifting power from a cheaper period that will take 30 to 50% off the electricity bill. For us the combination of summer savings via the solar and winter savings via timeshifting power means it will pay for itself several years sooner than just via the solar, the duration of which was what had been putting me off beforehand. My rough estimate brings it down from about 12 years to 8 but will not know for sure until it's (eventually!) used in anger.

I would like to see that properly costed.

Every time I look at battery storage, on the basis of using it to charge with free electricity from my solar PV for use later, I keep finding that the payback time is so long, the batteries are probably in need of replacement by the time it has paid for itself.

 

[pedg]

I would like to see that properly costed.

Every time I look at battery storage, on the basis of using it to charge with free electricity from my solar PV for use later, I keep finding that the payback time is so long, the batteries are probably in need of replacement by the time it has paid for itself.

I ran some simulations a while back based on historical agile data and my solar data. Obviously contained a number of assumptions so not sure how accurate it would be in terms of calling it 'properly costed'.  Possibly some of the more interesting graphs on that site are the long term max, min and average cost ones (like this one on this page for the east of England https://www.energy-stats.uk/octopus-agile-eastern-england/) which shows that there has been a gradual downward trend on all 3 over the last year, though has levelled off more recently. When I set my simulation to use the data from the last 90 days rather than the last year it reduced the payback time by about a year. For info I got (and obviously still trying to get installed!) a LUX - LXP3600 AC Controller and 3 Pylon Tech 2.4Kw US2000 Lithium Batteries (plus delivery) for £3192.

 

[ProDave]

So that's 7kWh of battery storage.

Say I had that much spare from my PV otherwise going to waste and I could use that in the evening, that would offset £1 of electricity usage each day.  So that would take 3192 days or 8.74 years to cover the equipment cost.

Of course it would take at least double that in real life because there won't always be that much spare PV. So 17 years.  How good do you think the batteries would be by then?

If you can "buy" the power in for £0 at the right time and use it to offset in the peak period on the agile tariff when it might be 30p or more then it just might begin to make sense.

Can you program it when to charge and when to discharge based on time of day to match the agile tariff?

 

[pedg]

So that's 7kWh of battery storage.

Say I had that much spare from my PV otherwise going to waste and I could use that in the evening, that would offset £1 of electricity usage each day.  So that would take 3192 days or 8.74 years to cover the equipment cost.

Of course it would take at least double that in real life because there won't always be that much spare PV. So 17 years.  How good do you think the batteries would be by then?

If you can "buy" the power in for £0 at the right time and use it to offset in the peak period on the agile tariff when it might be 30p or more then it just might begin to make sense.

Can you program it when to charge and when to discharge based on time of day to match the agile tariff?

You can. One of the reason I went for the model I did is someone has written an automated program to do that for you. Even if you can't buy at zero, if the lowest if 5p say, the average outside the peak period is 9 and the peak is 20. If you load the battery up (if needed) at 5p and discharge during the 20p peak you are going to be paying about 8p per kwh average for the day. Add that saving into that for the stored solar and its pays off a lot quicker. After a while the capacity of the batteries will drop but my thought there is that at that point I can probably get hold of a similarly used battery for a few hundred quid, add that in parallel with 3 I have and get back to close to the original capacity. The other point for us is that the variable tariff is good for charging an EV so that throws in some more savings and the battery means we don't have think too much about what electricity we are using on what in the peak period.

On the subject of the original question I have managed to arrange for a local spark to come and visit next week so I think I will mark the first suggestion to just get a spark in as the answer.

 

[binky]

I would like to see that properly costed.

Every time I look at battery storage, on the basis of using it to charge with free electricity from my solar PV for use later, I keep finding that the payback time is so long, the batteries are probably in need of replacement by the time it has paid for itself.

batteries have vastly improved with the move to Lithium. Payback tends to be long as most people will only discharge the battery once a day, which usually returns about 12 years as a payback when I do some rough numbers. However, with an electric car to flatten the battery. the number of cycles per day could easily be 2 ( but not in winter) , so payback would then be 6 years, but then if you can charge the car battery, does it make sense to have the AC battery?  To me, batteries really suite people who just hate the energy companies and are prepared to pay as little as possible to them, but the numbers are getting better all the time.

 

[Murdoch]

^^ lithium has problems such as its a very finite resource, coming from not so friendly countries

 and it can’t really be recycled properly yet

 fuel cells anyone?

 

[pedg]

batteries have vastly improved with the move to Lithium. Payback tends to be long as most people will only discharge the battery once a day, which usually returns about 12 years as a payback when I do some rough numbers. However, with an electric car to flatten the battery. the number of cycles per day could easily be 2 ( but not in winter) , so payback would then be 6 years, but then if you can charge the car battery, does it make sense to have the AC battery?  To me, batteries really suite people who just hate the energy companies and are prepared to pay as little as possible to them, but the numbers are getting better all the time.

The reasons we are going for a battery now are:

Better use of the solar

When no solar can take advantage of variable tariff to save money

The variable tariff allows cheaper charging of an EV

Less worry about using electrical appliances in the peak period.

I am a nerd and enjoy spending time trying to optimise the whole thing

(not necessarily in order)

 

[binky]

The reasons we are going for a battery now are:

Better use of the solar

When no solar can take advantage of variable tariff to save money

The variable tariff allows cheaper charging of an EV

Less worry about using electrical appliances in the peak period.

I am a nerd and enjoy spending time trying to optimise the whole thing

(not necessarily in order)

Nothing wrong with being a nerd, one of my best customers taught me an awful lot about PV. He installed air con (this was before batteries) to use leccy in summer / provide some heating in cooler times of year. Built his own website linked to local Univesity weather station etc etc. The sort of stuff I always think about doing, but never actually do! 

Out of interest, what do you think the financial gain for you is? 

 

[pedg]

Nothing wrong with being a nerd, one of my best customers taught me an awful lot about PV. He installed air con (this was before batteries) to use leccy in summer / provide some heating in cooler times of year. Built his own website linked to local Univesity weather station etc etc. The sort of stuff I always think about doing, but never actually do! 

Out of interest, what do you think the financial gain for you is? 

Difficult to be accurate as I am thinking of it more as a 3 part mutually beneficial thing with agile tariff, battery and EV.

On the EV side depends on how often it needs charging. Currently don't drive that much but when it becomes only a couple of quid to do say a return trip to the coast then expect may drive more. If we said as an example that we got a car with a 64KwH battery and had to do the equivalent of a full charge 2 times a month. If each kW going in a 10p cheaper (often get 2 or 4 p in agile) then that's 64 x 24 x 10p that's £62 a year. But the financial part is only part of the thing as there is also the reduction in climate guilt when you do go out in it and as I said makes driving for pleasure more attractive.

I expect the battery system to pay for itself in about 8 or 10 years plus obviously at the end of that time the system will still have some worth. But as with the EV as well as the financial part the battery removed (or at least reduces) the having to worry about when to do things like have the oven on or put the washing on. Can't be the only people with PV who currently go. 'Suns out, lets put some washing on' which can lead to 'lets not put the washing on yet there might be some sun later'. Having the battery means we could generally do these things whenever we wanted.

The aircon thing is sort of interesting as I see there is a move to try and eventually ban the sale of new gas boilers with people being moved more towards heatpumps as domestic gas heating contributes a large fraction of the CO2 produced in the UK. If that happens then I can see variable tariffs and batteries being more attractive as even with the energy advantage of heat pumps going to be quite a few kW to heat a house.

 

[pedg]

As a final point on this spark came round and has recommended upgrading to 100A and rewiring the whole lot to a single consumer unit using RCBOs and a surge protector.

 

[Murdoch]

As a final point on this spark came round and has recommended upgrading to 100A and rewiring the whole lot to a single consumer unit using RCBOs and a surge protector.

that sounds like a step forward

 have you been able to establish whether you can have a 100a fosse?

 

[pedg]

that sounds like a step forward

 have you been able to establish whether you can have a 100a fosse?

Having a visit from the DNO on the 11th and they say they will do the fuse upgrade at the time if they can. Spark coming to do the work next Friday so hopefully should be all nice 23mm wiring in place before then with cable direct to the consumer unit. Can't get the supplier in to do anything with the meter as on the cusp of changing suppliers at that point but spark does not think that will be a problem (as in legally, as far as I can tell, only the supplier should change the cables on the meter but that is not how it appears to work in practice).

 

[Murdoch]

Having a visit from the DNO on the 11th and they say they will do the fuse upgrade at the time if they can. Spark coming to do the work next Friday so hopefully should be all nice 25mm wiring in place before then with cable direct to the consumer unit. Can't get the supplier in to do anything with the meter as on the cusp of changing suppliers at that point but spark does not think that will be a problem (as in legally, as far as I can tell, only the supplier should change the cables on the meter but that is not how it appears to work in practice).

Thanks for the feedback - sounds like a good outcome for now and the future.

 

[pedg]

Thanks for the feedback - sounds like a good outcome for now and the future.

Assuming the work goes well. Assuming the fuse gets upgraded. Assuming the spark can be persuaded to do the final installation of the AC Inverter (they are going to have a look). Assuming no problem moving suppliers (as alleged smart meter has self-lobotomised itself) then hopefully fine!!

 

[Phoenix]

Nothing wrong with being a nerd, one of my best customers taught me an awful lot about PV. He installed air con (this was before batteries) to use leccy in summer / provide some heating in cooler times of year. Built his own website linked to local Univesity weather station etc etc. The sort of stuff I always think about doing, but never actually do! 

I always think one of the productive uses is if your EV is parked up in the day (possibly less rare than it used to be with WFH and all that, then as the chargers in the cars are generally constantly varible, then theres scope for a ev supply point that takes input from a few CTs (main tails, its own output or supply circuit and the PV circuit) and works out the best charge rate (this is communicated to the EV via the PWM rate on one of the pilot pins btw) to dump all the spare solar energy into the EV battery, rather along the lines of those immersion heater controllers you used to get. Not sure if theres such an item yet

 

[ProDave]

I always think one of the productive uses is if your EV is parked up in the day (possibly less rare than it used to be with WFH and all that, then as the chargers in the cars are generally constantly varible, then theres scope for a ev supply point that takes input from a few CTs (main tails, its own output or supply circuit and the PV circuit) and works out the best charge rate (this is communicated to the EV via the PWM rate on one of the pilot pins btw) to dump all the spare solar energy into the EV battery, rather along the lines of those immersion heater controllers you used to get. Not sure if theres such an item yet

I know someone that did that successfully with a Toyota Prius PHEV, though the response time to variations in charge demand rate were not very fast.

He has never been able to get that to work now he has a Tesla, it seems to ignore the "standard" input signals.

This sort of thing is firmly in "boffin's" territory at the moment, when it should be a mainstream standard product.

 

[Phoenix]

I know someone that did that successfully with a Toyota Prius PHEV, though the response time to variations in charge demand rate were not very fast.

He has never been able to get that to work now he has a Tesla, it seems to ignore the "standard" input signals.

At between 3% and 7% on the duty cycle it seems to drop into a mode where it sounds like it sends data over the pilot pins to set it all up, so I guess thats what goes on with the Teslas, they do seem to be like the Apple of the EV world. I imagine it would probably be possible to decode whats going on, but the level of boffin-ry required goes up.

I don't understand the need for it, the standard communications set up gives plenty of control over what you need, and is well documented and simple enough that it doesn't require complicated hardware to interface with.

 

[binky]

the idea of using your car as your PV battery and even backfeeding the house has been knocking around for a while, although I never saw much point of discharging from the car to power the house.

 

[Phoenix]

the idea of using your car as your PV battery and even backfeeding the house has been knocking around for a while, although I never saw much point of discharging from the car to power the house.

Agreed, best just use it for driving otherwise its pointless wear on the battery.

Any products you know of which do more or less what I describe?

 

[binky]

Agreed, best just use it for driving otherwise its pointless wear on the battery.

Any products you know of which do more or less what I describe?

nothing springs immediately to mind, but I don't install much battery equipment. Everything I have fitted seems to have lots of programming options which I have mostly ignored as surplus to requirement. I've always worked on PV charges battery, and battery release energy as and when needed.