Solar panels , would you ?

Last year we got 8 panels, 2 of them flattish, to generate just under 3000 kWh. South facing with a slight east angle to it. I wish we could fit 4 or 6 more, we just can’t.

If the roof side you plan to put 8 on can take a couple more I would add to it. If you look at the panel prices in relation to installation cost it’s almost always worth it.
 
harpo_72 said:
This is interesting, I wasn’t thinking about charging the car from the battery, more the solar or what was required. My intention was to try and be less dependent on the suppliers.
I also wanted be unaffected by their problems ..
My roof can take 46 panels but that’s not all going to be optimum positioning and a bit expensive.. yes I could sell back to the grid during the summer a huge amount but I thought the buy back tariffs were fickle?
My plan was to pop in 6-8 panels in the optimum position and at 80% efficiency they would supply and charge up the Tesla wall in 5 days then it would be case of supporting me and exporting. Winter would not be so great but that’s okay.
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Winter is where you tell the powerwall to charge up every night to 100% and bingo you would never need worry

Charging the car off solar is ok but as the export is worth more than buying from the cheap rate it seems a waste

You can set the PW up to say Nov to march charge every night and rest of year to go off solar usage etc

8 panels seems small. However you have to speak to dno about what they will let you export.. mines set to 3.6kwh need g99 to go to 5kwh
 
PJ87 said:
Winter is where you tell the powerwall to charge up every night to 100% and bingo you would never need worry

Charging the car off solar is ok but as the export is worth more than buying from the cheap rate it seems a waste

You can set the PW up to say Nov to march charge every night and rest of year to go off solar usage etc

8 panels seems small. However you have to speak to dno about what they will let you export.. mines set to 3.6kwh need g99 to go to 5kwh
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I think a 2 tier tariff would be a sensible direction and as you all have suggested export at a higher rate than import.. meaning possibly a smaller battery and bigger array
 
larmen said:
Last year we got 8 panels, 2 of them flattish, to generate just under 3000 kWh. South facing with a slight east angle to it. I wish we could fit 4 or 6 more, we just can’t.

If the roof side you plan to put 8 on can take a couple more I would add to it. If you look at the panel prices in relation to installation cost it’s almost always worth it.
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What is the overall efficiency of the array on a sunny day?
 
harpo_72 said:
I think a 2 tier tariff would be a sensible direction and as you all have suggested export at a higher rate than import.. meaning possibly a smaller battery and bigger array
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Is islanding that important? Or just go for a battery that would cover your day usage but would need you to throw a switch to be used when the grid is down.. I mean save a bit to have a sparky do it rather than Tesla

Can go on agile tariff.. program a home assistant to manage your battery then it charges at the cheap slots, and exports when they pay the most etc etc .. people are making lots of money that way aswell

I can't cuz they don't work with Tesla but I'm happy with my low bills for My high use (£500 net for 9100kwh)
 
harpo_72 said:
Does this sound reasonable
46 panels x 0.460 kWh x 25% x 6 hrs x 140 days x £0.15 by back - 6x consumption at 1.8kWh ?
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calc aside, there is a new build house near us... he has about 50 plus panels across 2 roofs on the front of the house. Since it is a new build, they have it inset. Actually it looks pretty decent. I am assuming he can power the neighbors.

My assumption is that, If u put 48 panels, and you dont use gas for heating, then you will be pretty much off grid the whole year..
 
All you guys contemplating installing dozens of panels...
Bear in mind that you need special permission to inject more than 16A (~4kW) into the grid.
And you'll need some serious inverter tech to handle that amount of power.
Just sticking loads more panels on the roof isn't a walk in the park.
 
I have been calculating my leanest most efficient system. I still think with our usage and combination of a 2 tier tariff we would be okay. So I worked on my panels being 80% efficient for 11 hours on my south facing rooftop and this will drop to 30% and then 10% during autumn/spring and winter respectively.. this would mean 8x0.440 kw panels and 3.6kw battery would turn a profit in summer that will cover electric usage in winter.
But if I understand correctly there are immersion heater systems you can add to the water tank that would also reduce gas consumption?
 
harpo_72 said:
I have been calculating my leanest most efficient system. I still think with our usage and combination of a 2 tier tariff we would be okay. So I worked on my panels being 80% efficient for 11 hours on my south facing rooftop and this will drop to 30% and then 10% during autumn/spring and winter respectively.. this would mean 8x0.440 kw panels and 3.6kw battery would turn a profit in summer that will cover electric usage in winter.
But if I understand correctly there are immersion heater systems you can add to the water tank that would also reduce gas consumption?
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8 panels over the year.
Generation, generation by day, value of kWh generated, percentage of load covered by solar.
Basically, discover the year the electricity is covered, standing charges are not.

Solar inverters seem to be a thing of the past as you can heat cheap at night and sell more expensive if you have surpluses. Like the EV thing.
 

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harpo_72 said:
I have been calculating my leanest most efficient system. I still think with our usage and combination of a 2 tier tariff we would be okay. So I worked on my panels being 80% efficient for 11 hours on my south facing rooftop and this will drop to 30% and then 10% during autumn/spring and winter respectively.. this would mean 8x0.440 kw panels and 3.6kw battery would turn a profit in summer that will cover electric usage in winter.
But if I understand correctly there are immersion heater systems you can add to the water tank that would also reduce gas consumption?
Click to expand...

Yes you could get a immersion heater use the night tariff and then soler divert to top up, I wish I had space. Then id go induction hob, heat pump and long off gas
 
harpo_72 said:
But if I understand correctly there are immersion heater systems you can add to the water tank that would also reduce gas consumption?
Click to expand...
It's worth bearing in mind that gas per kWh is less than half the price of what you can export your spare generation for.
So unless immersions are more than twice as efficient as gas water heating, it doesn't make sense to use a diverter.
(And from a brief online search, it would appear that heating water by gas is about 85% as efficient as an immersion).
 
PJ87 said:
Yes you could get an immersion heater use the night tariff and then soler divert to top up, I wish I had space. Then id go induction hob, heat pump and long off gas
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I think the wife wants an induction job but heat pump no, I don’t think we would justify it until we get the double glazing sorted, the odd infra red plate might be useful.. but the resistance is strong in my wife
 
Thought I would give this a bump now as we are seeing longer days. Have any of you that have installed systems looked at your generation and impact it’s having to your consumption?
 
harpo_72 said:
Thought I would give this a bump now as we are seeing longer days. Have any of you that have installed systems looked at your generation and impact it’s having to your consumption?
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I only have up to date stats for January. Generation was 106 (down from 136 in Jan 24), of which 74 was exported (70%). Not much different to the year overall, which saw 75% of generation exported.

Most of our consumption is in the evening, so no surprise the majority of generation is exported. I've done the sums to see if adding a battery would help, but the return on investment would be negligible. (Better to leave the money in an ISA)
 
Figures in for February

Billed cost £62.50
Export paid to me £1.46
Total energy consumption 790.9 kWh
Cost without set up £217.66
Savings this month £156.62

Savings in year 3 thus far (may to may )£1625.84

Savings to date £5166.69

Left to pay off £10155.09

Should be paid off in 5 years but if not
definitely within 7
 
Haven’t done February numbers yet, but year to date was awful. March is looking much more promising.


Has anyone else seen the fully charged video about vehicle to grid? I think they rolled it out in Australia now. Basically giving you a 40+ kWh home storage battery you can take with you.
 
larmen said:
Haven’t done February numbers yet, but year to date was awful. March is looking much more promising.


Has anyone else seen the fully charged video about vehicle to grid? I think they rolled it out in Australia now. Basically giving you a 40+ kWh home storage battery you can take with you.
Click to expand...

March has been fantastic so far.. but last few days of Feb been cracking aswell. Been exporting a bit .. but buying much less from grid. 11kwh last night compared to 21 night before
 
This February we generated 5 kWh more than last year, and last year had 29 days. It therefore was better ;-)

But I think we used a lot more electricity, no idea why. And last year we had better saving sessions from Octopus, so we are down oblast year overall.
 
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