Solar panel production figures

December and Jan were pretty meh though, also you can get shading late in the year from low sun that you don't get in middle of summer.

Still more than 100kWh for both months for me, and 100kWh is still good/useful.
 
squerble said:
Certainly puts in a dent in the "only works in summer" naysayers!

EDIT: those with solar and batteries, are you manually managing your battery charging overnight to account for potential sun the next day?
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I personally don't as I'm not on an eco 7 or Go tariff. However you can automate it to do exactly that, charge when the rate is cheap automatically. It's a very cost effective way of managing your electrcity.

And you're 100% right, even in nov/dec/jan we were getting over 100-200kWh of generation so the naysayers know nothing Jon Snow.
 
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I worked out my per string thingy in a sort of hacked together way but I think the maths checks out.

My inverter stores data at 5 min intervals for per string W values.

My logic is that for a given day. The total output generation (yesterday 10.3 kWh) is abstracted from the sum of the W generation per string, as a portion of it's sum.

So I took the sums per string, W facing string was somewhere around 40K, W facing string was somewhere around 80K yesterday. Combined around 120K.

Therefore my S facing string was responsible for (80K / 120K) = 66.6666r % of my 10.3 kWh yesterday or around 6.87 kWh. W facing string the remainder, 33.3333r % or 3.43 kWh.

Back in my best day so far (September 21st) this was more like 60% S facing and 40% W facing, so will be interesting to see how this figure changes over the year.

Interesting side quest: Peak generation on that best day was 1.9kW against the 2.2kW of panels on S string, and 1.6kW against the 2.6kW of panels of W string. I'll keep an eye on this because in ideal conditions both should be close to the limit. It's not impossible for 1 or more of the W facing panels to not be wired up properly or working, hard to validate with a string.
 
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Freefaller said:
I personally don't as I'm not on an eco 7 or Go tariff. However you can automate it to do exactly that, charge when the rate is cheap automatically. It's a very cost effective way of managing your electrcity.

And you're 100% right, even in nov/dec/jan we were getting over 100-200kWh of generation so the naysayers know nothing Jon Snow.
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Yea, so if I (hypothetically) had solar now with our GO tariff, I'd have the 4 hour window to charge a battery, however I would have thought it'd be worth hedging your bets to only charge it 25% (or not at all) if you're expecting a lot of solar generation the next day? That way, you'd have "free" electricity, which is even cheaper than the 7.5p/kWh I'd be charged overnight, so it wouldn't even matter if your export rate is low at 4p/kWh or whatever people get these days?

If you get 20kWh today then that's a full battery charge (usually around 9-10kWh) and more
 
squerble said:
Certainly puts in a dent in the "only works in summer" naysayers!

EDIT: those with solar and batteries, are you manually managing your battery charging overnight to account for potential sun the next day?
Click to expand...

It's a little risky but on a day like today I could have pushed it more, the downside is if Solcast is wrong, you'll run out of power and pay extra.

Every kWh I import is 7.5p overnight, and I get 4.1p export, so the cost of charging to 100% every night is 3.4p per excess kWh I import. I pay 40p peak rate so any missing are expensive.
 
HungryHippos said:
I worked out my per string thingy in a sort of hacked together way but I think the maths checks out.

My inverter stores data at 5 min intervals for per string W values.

My logic is that for a given day. The total output generation (yesterday 10.3 kWh) is abstracted from the sum of the W generation per string, as a portion of it's sum.

So I took the sums per string, W facing string was somewhere around 40K, W facing string was somewhere around 80K yesterday. Combined around 120K.

Therefore my S facing string was responsible for (80K / 120K) = 66.6666r % of my 10.3 kWh yesterday or around 6.87 kWh. W facing string the remainder, 33.3333r % or 3.43 kWh.

Back in my best day so far (September 21st) this was more like 60% S facing and 40% W facing, so will be interesting to see how this figure changes over the year.

Interesting side quest: Peak generation on that best day was 1.9kW against the 2.2kW of panels on S string, and 1.6kW against the 2.6kW of panels of W string. I'll keep an eye on this because in ideal conditions both should be close to the limit. It's not impossible for 1 or more of the W facing panels to not be wired up properly or working, hard to validate with a string.
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I don't think pure E or W will hit 100% since the time they would be directly facing the sun would be too early or too late in the day.
Maybe when its very close to summer solstice. Where as S facing will have a wider period of the sun "being overhead" and being lined up for max generation.

Interesting to track though, I am kind of doing the same, where I have multiple 5 minute readings I take the peaks (not spikes as they could be mis reporting).
Will give me a fairly good trend line for the year.
Shame you cant just magic up a couple of years of data :)
 
squerble said:
Yea, so if I (hypothetically) had solar now with our GO tariff, I'd have the 4 hour window to charge a battery, however I would have thought it'd be worth hedging your bets to only charge it 25% (or not at all) if you're expecting a lot of solar generation the next day? That way, you'd have "free" electricity, which is even cheaper than the 7.5p/kWh I'd be charged overnight, so it wouldn't even matter if your export rate is low at 4p/kWh or whatever people get these days?

If you get 20kWh today then that's a full battery charge (usually around 9-10kWh) and more
Click to expand...

My export is 15p as I'm not on Go. But yes you're spot on. Today I'm doing laundry and dishwasher and the dehumidifier is on. My batteries are already full! So it's all export from now on really.

As for prediction solcast works well enough it's always a best guess though. You can control your charge rate, up to the max your inverter can give at exactly the time slots you want. HH here is on Go I think and does that technique.
 
HungryHippos said:
It's a little risky but on a day like today I could have pushed it more, the downside is if Solcast is wrong, you'll run out of power and pay extra.

Every kWh I import is 7.5p overnight, and I get 4.1p export, so the cost of charging to 100% every night is 3.4p per excess kWh I import. I pay 40p peak rate so any missing are expensive.
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With hot water diverter and current gas pricing and elec pricing on Go its a no brainer for me to charge fully even if solar generation will be high.
Gas at around 7p (flexible) assuming 90% efficiency at water heating will mean the cost to add via gas and via Go are the same.
Whilst technically go isn't heating the water, diverting watts that would have gone into the battery to the water is the same real world effect.

As ever with this solar lark, its a snapshot of pricing and generation. And that equation can change regularly.
 
HungryHippos said:
Today definitely looking a bit tastier than yesterday, I hope it stays like this because a once in a while all sunny all day thing lets you see where system potential lies at this time of year.
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Yeah, not a cloud in the sky today so it's pretty much going to show peak performance for me I think - oddly enough the peak power was lower today (a smooth topped 3.87kw vs a 4.38kw spike yesterday) which I don't really understand.

I've already hit 14.8kwh and it's not even 2pm yet, still generating over 2kw on the panels.... going to be interesting where it ends up. Pretty happy with that given the shading issues I have from the neighbours roof this time of year. Yet again I overcharged the packs at night even though I only put about 5kwh in... Weather looks pretty good for next couple of days so might forgo a charge and see how it goes.

Edit - I find it interesting looking at the strings just how much of an effect shading has. Even though I’m optimised the string that has about 40% shading is outputting 1/5th the power of the unshaded string. My ignorance had assumed that it would be somewhat linear with roughly half the output.

Wasn’t really fully aware of how it all worked, but having some shaded panels actually drags the string performance right down… in some situations you could actually be better off with less panels rather than having more panels but with some shaded.

Makes more sense to me now why the installer strung it the way he did with the roof effectively split into left and right… as the day progresses the right hand string stays unshaded for most of the productive hours of daylight.

Looking forward to the sun getting that bit higher in the sky and my shading issues to go away, then it should really rip!
 
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squerble said:
Certainly puts in a dent in the "only works in summer" naysayers!

EDIT: those with solar and batteries, are you manually managing your battery charging overnight to account for potential sun the next day?
Click to expand...

Not had to charge my batteries from the grid at all this month yet.
They run the house 19 hours a day on the peak rate, batteries off during cheap rate(5hours)
 
Troop said:
Not had to charge my batteries from the grid at all this month yet.
They run the house 19 hours a day on the peak rate, batteries off during cheap rate(5hours)
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Speaking of I noticed in your screenshots with Ron-Ski your battery had only been cycled 20 odd times.

My 8.2kWh GE battery has been cycled over 200 times since I had it installed start of September last year!

More than once per day on average :cool:

Their warranty info states unlimited charge cycles on it though, but it seems they kind of put fair use at 500 cycles per year.
 
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Freefaller said:
What's the size of your batteries @Troop ?
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17KW, but more to be built this year, the solar that charges them is only 1.5kw

We are low users of electric now, 7-8 years ago we were using close to 9000KW per year (storage heaters)
This year target is under 1000kw from the grid with 98% at the cheap rate (Octo GO Faster)

Don't know if I'll make it under 1000KW, the immersion will use 650kw over the year for hot water

Our rental property generated close to 3500kw per year, so I'm net exporting to the grid overall, plus the rental pays 22p(FIT)a unit for those 3500kw
 
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Nice! Days like today makes me think we should have another battery (9.5kw).

We are as a family of 4 relatively high users of energy, although when idle at night (when everyone's asleep) it's no more than 200W or so. However we don't have a gas hob or oven, so everything is electric, and we like to cook, so the oven and hobs are on a lot!
 
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