Solar Power

Home Solar PV Panels Upgrade Finished

Our new 1.6kW solar array has now been fitted and is working much better than we expected

Following from the Solar Upgrade Solis 1.5kW inverter and Raspberry Pi RS485 Logging blog post, the houses’ front roof has now been replaced with new insulation and slates we have been able to install the new solar rails and panels to the house.

Our original plan was to install five JA Solar 340W Mono panels but after ordering these we were told that they are not available. After a few days the supplier was about to source 330W panels which are the same dimensions.

The roofers installed the new stainless-steel brackets into the roof rafters and fitted the waterproof flashings around the brackets to seal the roof.

Brackets fitted to the roof rafters
Brackets fitted to the roof rafters

The roof rails are fitted using M8 bolts which clamp into the bottom of the rails and the solar panel brackets fit into slots on the top of the rails.

The new panels measure 1689 x 996 x 35mm and we fitted these onto 3.3-meter rails with 2 on the top row and 3 below which will give us a theoretical maximum output of 1.6kW which is suitable for the Solis Solar 1.5kW Mini 5G Inverter.

Solar rails fitted
Solar rails fitted

To make the installation of the panels easier we fitted lengths of angle aluminium to each panel into existing mounting holes so the panels could rest over the rails and not slide down before the panel mounts were fitted. This also made lifting the panels to the roof and into the rails easier as we could use a rope to lift them to the scaffolding.

Panels fitted
New panel array fitted

Solar Power Generation

The old solar installation which was 500W total was generating between 1.3 and 1.9 kWh per day (June 2022) and the new 1.65kW array is generating up to 10 kWh per day.

Daily generation graph
Comparison between the old daily generation with 500 watts of panels vs the new 1.6kW panels

Now we have three panels below the chimneys and the sun falls on these panels much earlier in the day compared to the old array. Where we still have two panels between the chimneys they still have shadows over one panel early in the day.

The solar generation graph below shows an average July day with the panels starting to generate a small current at 6 am but the energy doesn’t increase until the sun is on all five panels at 8 am.

Daily generation watts curves
Daily generation watts curves showing increase as panels come out of shadow in the morning

The current reaches 1000 watts around 10am and stays above this value until mid afternoon when it slowly ramps down until 7pm.

Ordering Solar PV Optimisers

The panels were initially installed without optimiser modules on the top two panels, and after a few weeks of use we decided to order a pair of Tigo TS4 Add-On Optimised Modules from veepenergy.ie as the scaffolding to fit them was still in place.

When we placed the order on the 10th July we selected the 1 day UPS delivery option and after 3 days we received an email to say the parcel was waiting collection. I emailed the company several times over the following week to ask for updates, but they did not reply to any messages.

Eight days after we placed the order, we were told that the scaffolding was being removed and so we wouldn’t be able to fit the new optimisers. After receiving this news, I emailed Veep Energy asking them to cancel the order as it had still not been sent. The following day I received an email to tell me that the order had been shipped!

As we cannot access the roof safely without scaffolding, we will not be able to fit the optimisers when they are delivered. With the cost of having new scaffolding erected being around £800, it is not viable to have it installed again just to add the two optimisers.

Data Logging Updates

With the installation of the new solar PV inverter, we now had the total daily generation data available to store and use. I modified the online reporting site at home.briandorey.com to store and display the new information. This will be useful over time to compare our previous electricity usage and the new power generated from the roof.

Excess generation during July has been around 8 hours of the day and varies between 500 and 1000 watts. To make the most of this we have ordered a myenergi eddi which is a solar PV diverter to the hot water cylinder. This is due to be delivered in August and I will post on the blog once it has been installed and running for a few weeks.

Home assistant daily generation reports
Home assistant daily generation reports

Hardware Costs

Excluding the cost of the scaffolding which was included in the roofer bill the total parts cost of this solar PV upgrade was £2641.70

The panels, inverter, mounting brackets and rails came to £2036 with the remaining items such as fuses, cable, tools and conduit making up the total.

If we had paid an installer to install a 1.6kW system this would have cost over £4000 and so we saved a lot of money by installing these ourselves.

Huge Energy Cost Increases

In July our previous Electric and Gas supply contract was due to be renewed. We had previously been with E.ON Energy on a 24 month contract and despite checking with all the other large energy suppliers in the UK, we couldn’t find any who would accept new customers at this time.

We had no choice but to renew with a new 24-month contract, but the prices have greatly increased for the energy prices and daily standing charges taking our monthly payments from around £140 per month to over £350.

The energy price cap in the United Kingdom is set to rise again in October 2022 and again in January 2023 so I don’t know what the next energy contract will cost next time.

Service Old kWh price New kWh price Change Old Daily Charge New Daily Charge Change
Electric 18.83 p/kWh 41.03 p/kWh 118% 22.48 p/day 43.39 p/day 93%
Gas 3.44 p/kWh 10.52 p/kWh 206% 24.96 p/day 27.22 p/day 9%

Based on previous years the daily generation reduces by half in the winter months so it should average around 7.5kWh per day generation which should save approx. £3 per day or £1122 per year at current electricity rates.

At this level the payback time should be two and half years.

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