Talk to me about solar panels.

[Cue]

Nothing so fancy I'm afraid, just the Web based calculator from JRC and solcast. Both great for generalised info, not good for a specific spot. Best bet is to pop out at 10am, midday and 2pm to get an idea of shading in the best part of the day.

In other news I forgot to grid charge last night, so today I may use peak. Got about 7kWh useable in the battery

You can’t schedule it?

I’d be running HASS and Octopus Agile personally…

 

[tek-monkey]

You can’t schedule it?

I’d be running HASS and Octopus Agile personally…

I turned it off as we'd had a few days of sun, used half a kWh in 3 days, but knew today would be terrible and forgot to reschedule.

Home assistant is on my huge list of things to do whenever I get some free time!

 

[Cue]

I turned it off as we'd had a few days of sun, used half a kWh in 3 days, but knew today would be terrible and forgot to reschedule.

Home assistant is on my huge list of things to do whenever I get some free time!

Probably a good idea!

Also just to summarise, how much have you thrown at this project now? It’s probably here somewhere in the thread, but easier to just ask for an update.

There’s part of me that wants to pull a loan out to get batteries and solar but it depends on the cost. By the sounds of it we could cover the majority of our electricity usage (over £100 easy) per month, and with some fine tuning get some good grid dumping going on the sunnier days.

 

[tek-monkey]

Probably a good idea!

Also just to summarise, how much have you thrown at this project now? It’s probably here somewhere in the thread, but easier to just ask for an update.

There’s part of me that wants to pull a loan out to get batteries and solar but it depends on the cost. By the sounds of it we could cover the majority of our electricity usage (over £100 easy) per day, and with some fine tuning get some good grid dumping going on the sunnier days.

We spent roughly 13k in total, on 5.7kW of panels and 15.6kWh of batteries. For us, in winter, the batteries did all the work. We got enough to match our daily consumption plus a little extra, so charge at night on the cheapest rate then use in the day. In the summer thats a different matter, you fill the batteries from the sun, so a longer slower charge period but same result.

Now yours is for work yes? I assume you have the vast majority of energy use in the day, but must have overnight too? Sizing a battery to cover your days will be rather prohibitive, plus I don't think you'd get to charge them anyway without some serious inverters. You on 3 phase? Batteries can be added later anyway, whereas panels a lot of the cost is fixed installation stuff. Doesn't matter if you add 20 or 25 panels you still pay the roofers for the day, the scaffolding etc. so unless there is an economic reason not to I'd always cover the roof just to maximise winter production. If ground mounting I'd be more interested in matching panels to inverter to usage.

You any idea what size array you can do, and what inverters are available to manage that? £100 a day is a lot, but whats that in kWh? Whats your usual daily peak load?

Although don't get hung up on covering it all, as any reduction is a saving so as long as that saving negates the install cost in a timeframe thats OK with you is all that matters. Panels have a 25 year life, inverters more like 10 and batteries 10 or 6000 cycles, worth bearing that in mind.

 

[Cue]

We spent roughly 13k in total, on 5.7kW of panels and 15.6kWh of batteries. For us, in winter, the batteries did all the work. We got enough to match our daily consumption plus a little extra, so charge at night on the cheapest rate then use in the day. In the summer thats a different matter, you fill the batteries from the sun, so a longer slower charge period but same result.

Now yours is for work yes? I assume you have the vast majority of energy use in the day, but must have overnight too? Sizing a battery to cover your days will be rather prohibitive, plus I don't think you'd get to charge them anyway without some serious inverters. You on 3 phase? Batteries can be added later anyway, whereas panels a lot of the cost is fixed installation stuff. Doesn't matter if you add 20 or 25 panels you still pay the roofers for the day, the scaffolding etc. so unless there is an economic reason not to I'd always cover the roof just to maximise winter production. If ground mounting I'd be more interested in matching panels to inverter to usage.

You any idea what size array you can do, and what inverters are available to manage that? £100 a day is a lot, but whats that in kWh? Whats your usual daily peak load?

Although don't get hung up on covering it all, as any reduction is a saving so as long as that saving negates the install cost in a timeframe thats OK with you is all that matters. Panels have a 25 year life, inverters more like 10 and batteries 10 or 6000 cycles, worth bearing that in mind.

Oh sorry no I meant for home, and I typo’d it’s actually £100-150 per month on leccy. For work the landlord is more interested in doing it himself - but yes it’s 3 phase, and when the prices go up we’ll easily be doing £500+ bills per month with no night rate as the private meters on the individual units don’t have a night rate

How much was just the solar out of interest?

 

[tek-monkey]

Oh sorry no I meant for home, and I typo’d it’s actually £100-150 per month on leccy. For work the landlord is more interested in doing it himself - but yes it’s 3 phase, and when the prices go up we’ll easily be doing £500+ bills per month with no night rate as the private meters on the individual units don’t have a night rate

How much was just the solar out of interest?

The batteries were 2k each retail at the time for 5kWh, but not sure just taking that cost off the quote gives a true cost of the solar.

Panels are cheap, 200 each or so, getting them on the roof and wired up doubles that cost easily.

 

[Lucy]

Invertor fitters have arrived, before the panel people. They are scratching their head now they've realised how impossible it's going to be to get the power from the invertors in the loft to the fuseboard.

 

[Lucy]

And the specialist scaffolding company who came in the week have put scaffolding where we're getting one string and made it impossible for them to get their ladders up.

 

[tek-monkey]

That doesn't sound good! Can the inverter go near the fuseboard instead of the loft?

For me both arrived together, they discussed what was happening then once an agreement was made both started work, which is just as well as we had our plans changed at the last minute.

 

[Lucy]

No, we've got very little space there. We've given them a suggestion but they are trying to get the OH chase out the wall. He's refused given how much we're paying.

 

[tek-monkey]

No, we've got very little space there. We've given them a suggestion but they are trying to get the OH chase out the wall. He's refused given how much we're paying.

As in they want you to do the work? Or they want to chase out the wall, which you don't want them to do?

 

[Lucy]

They want us to do the work. Chasing out is the only way they aren't leaving exposed wires and we are not having exposed wires.

 

[tek-monkey]

They want us to do the work. Chasing out is the only way they aren't leaving exposed wires and we are not having exposed wires.

So the surveyor basically didn't do his job, and the installers don't want to do the work. I'd call the company and ask what they suggest, then likely cancel the contract as they have been unable to fulfil their end of the bargain. I assume you paid the deposit on a credit card?

 

[Lucy]

Pretty sure we haven't even paid a deposit. Rails are already going up. Just asked me to agree to have a bit of trunking in the corner of the kitchen that they'd box it. Nope.

 

[tek-monkey]

Pretty sure we haven't even paid a deposit. Rails are already going up. Just asked me to agree to have a bit of trunking in the corner of the kitchen that they'd box it. Nope.

And this was discussed with the surveyor, no outside wires?

 

[Lucy]

He didn't even ask. Happy for exposed wires on the outside of the house, but not inside.

 

[tek-monkey]

He didn't even ask. Happy for exposed wires on the outside of the house, but not inside.

Sorry, misunderstood.

I guess my install was easy, as it ended up on the flat roof I didn't want the wires to enter the house til the consumer unit anyway, so they just trunked down the outside then entered exactly where needed.

 

[Lucy]

Yea, the issue we have is next door have a wall about an inch from the side of the house the consumer unit is on, so it's impossible to come in there, which is under the stairs so I'm not bothered about exposed wires there. It's why the EV charger install was a pain too.

 

[tek-monkey]

Yea, the issue we have is next door have a wall about an inch from the side of the house the consumer unit is on, so it's impossible to come in there, which is under the stairs so I'm not bothered about exposed wires there. It's why the EV charger install was a pain too.

How are they getting on? Sorted anything?

 

[Lucy]

Yes, there's one stud wall in the whole house that happens to be upstairs. They've cut a small hole in that to feed it through, then under the floorboards to get it to the consumer unit.

8 of the 12 panels will be up today but the other 4 won't go on until the specialist scaffolders come and take down what they've blocked (and fix the tiles they've broken).

Powerwall has a longer lead time so we won't be able to store any energy for a while.