Pink Duck
Active Member
Charge, discharge, repeat 
all night long.
PW2 in time-of-use mode might actually do that already.
all night long.PW2 in time-of-use mode might actually do that already.
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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
phil4
Member
I tried it quickly today, it went from 3kW solar doing 1kW to the house and 2KW to the PW, to 2.5kW being exported and PW powering the half the house, the other 0.5kW from solar. Just by changing the outgoing rate in the Time of Use Utility rates section.Charge, discharge, repeat
PW2 in time-of-use mode might actually do that already.
The cost per kWh and battery cycles don't really work, I tried the maths already.Charge, discharge, repeat
PW2 in time-of-use mode might actually do that already.
My battery is warrantied for 5000 cycles, so I could make £375/kWh from it, realistically the purchase price is more like £500/kWh.
phil4
Member
I'm not allowed to discharge from my batteries, so as above, I'll let it juggle it, exporting most of the solar, and the battery powering the house.
net result still similar though? if you bias your solar towards export you could be cycling your batteries more to run the house where in summer you might only float between 60-100% running off solar mainly for the house and only battery overnight.
phil4
Member
I'm not saying you're wrong. But my thinking the battery is being used one way or another.
At the moment, it charges on excess solar during the day and then discharges in the evening/overnight, topping up a little if tomorrow is overcast. So goes down and back up.
With this, it'll be doing the same, but it'll be mains power bringing it back up, not solar.
For context, my array size, 5.33kW isn't exactly big when the house uses typically 20kW before car charging.
For Go, I guess it makes most sense to charge to 100% during off peak (+Dishwasher, Washing Machine, EV), recharge and export from solar, and think about discharge in the evening. Technically nothing stopping you doing that between 9:30pm and 00:30...
Seems a bit weird, especially as agile isn't providing that level of export payment.
Seems a bit weird, especially as agile isn't providing that level of export payment.
WannabeOwner
Well-Known Member
Is this getting towards the point of making PV install worthwhile (just for the export)?
scdoubleu
Member
We're on the Scottish Power 12p/kWh SEG and, up until today, Octopus Go. Now on IO. I set the import/export rates in the Tesla App for our Powerwall (which is not permitted to export). As SEG is higher than the off-peak import tariff the Powerwall will, of its own volition, charge to 100% during the off-peak period to maximise solar export during the day, using some solar to keep itself topped up enough to see us through to the end of the peak period.
It makes zero sense to charge our cars from solar with this price differential, but feeding our solar to our neighbours is still a win for the environment.
We've exported 14 kWh of solar today, out of 33 kWh generated so far (A2A heat pumps working hard), resulting in a small net profit for the day. We're about £1.50 up over the last four days, though haven't done any EV charging during that time.
On a related note, we're coming up to the two year anniversary of our Solar/Powerwall installation. SWMBO's spreadsheet reckons we will break-even in 5 years time. With the increased SEG rates, this could happen sooner still. PV + battery is such a no-brainer now.
It makes zero sense to charge our cars from solar with this price differential, but feeding our solar to our neighbours is still a win for the environment.
We've exported 14 kWh of solar today, out of 33 kWh generated so far (A2A heat pumps working hard), resulting in a small net profit for the day. We're about £1.50 up over the last four days, though haven't done any EV charging during that time.
On a related note, we're coming up to the two year anniversary of our Solar/Powerwall installation. SWMBO's spreadsheet reckons we will break-even in 5 years time. With the increased SEG rates, this could happen sooner still. PV + battery is such a no-brainer now.
if 100% DoD thats about 23p a day profit assuming you fill up overnight at 7.5p/kwh. so only 12-15 years to pay back the battery costs then you're quids in.
but in reality:
if you have 2 exports from same battery a day - then it is let's say 6 kwh @ 15p - 90p a day! of it, 1 would be charged at 7.5p - so 3.5 x 7.5 = 26.25
so total net of the day can be 90-26.25 = 63.75p
that is totally theoretical.. practically impossible ;D
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Ooh, I'll try this then - then call them when it doesn't work.......I spoke with Scottish power. Apparently using chrome is an issue for SEG application. Silly me
PITA
Model 3 Performance
That thought has gone through my mind.
Keep the Powerwalls at 100%
Cars at 80%
Pump everything else back to the Grid. It's going to be very weird Summer next year.
PITA
Model 3 Performance
I just had another thought.
We have 3-Phase... and our existing Solar Array is on Phase-1
If I installed another array on Phase-2 ... it's only job could be to export. Export it all.
That would off-set a lot of incoming costs, and still pay for itself.
Probably get another 5kW inverter and export at 10kW (5kW x 2)
We have 3-Phase... and our existing Solar Array is on Phase-1
If I installed another array on Phase-2 ... it's only job could be to export. Export it all.
That would off-set a lot of incoming costs, and still pay for itself.
Probably get another 5kW inverter and export at 10kW (5kW x 2)
ACarneiro
Active Member
Got that email too.
Almost seems to good to be true, just waiting for the catch…
ElectricPolice
Member
Maybe I’m about an average install size with regulation 3.68kW inverter and 12x 390W panels and 13kW batteries (maybe a little higher on battery
) Yesterday perfect solar profile of zero % cloud generated 27.4kW solar and I exported 7.2kW. So far this year export 560kW and all of 2022 was 820kW.
That said I optimised usage over export as we all have. Who knows what I would have exported if I hadn’t diverted to the cars or washed the curtains, steamed the carpets or did anything else to save exporting !!
Surely process now is fill up battery to 100% overnight, do car charging, washing and everything else in the IO window and let solar max out throughout the day so it keeps battery full, house powered and max export.
If I had a little more intelligence and a lot less other stuff to do (like work) then I suppose I should discharge the battery fully before 11:30 and repeat?
I guess it makes these evenings alone in a hotel a little more fulfilling
.
Like others perhaps I’m missing something?
We’re not talking massive savings but if it flattens the bills a little it’s a win for me.
) Yesterday perfect solar profile of zero % cloud generated 27.4kW solar and I exported 7.2kW. So far this year export 560kW and all of 2022 was 820kW.That said I optimised usage over export as we all have. Who knows what I would have exported if I hadn’t diverted to the cars or washed the curtains, steamed the carpets or did anything else to save exporting !!
Surely process now is fill up battery to 100% overnight, do car charging, washing and everything else in the IO window and let solar max out throughout the day so it keeps battery full, house powered and max export.
If I had a little more intelligence and a lot less other stuff to do (like work) then I suppose I should discharge the battery fully before 11:30 and repeat?
I guess it makes these evenings alone in a hotel a little more fulfilling
.Like others perhaps I’m missing something?
We’re not talking massive savings but if it flattens the bills a little it’s a win for me.
