Contractor Blog

Erica Charles

Managing Director of Spirit Energy.

Recent Posts

Solar Panel Specifications: Reading a Solar Panel Datasheet

Erica Charles · 25 Jul 2019

Solar panel key parameters

If you are trying to compare one PV panel to another, it is helpful to understand the key technical parameters - or solar panel specifications - that impact performance.

With this in mind, we’ve taken some extracts from the specification sheet for a standard polycrystalline solar panel (Trina Solar’s HoneyM Plus+ 265-275W range) and highlighted the key parameters.

We’ve then highlighted key differences between the Trina panel and SunPower’s Maxeon® 3 panel.


Topics: Solar PV

Bifacial Solar Panels and the Albedo Effect

Erica Charles · 01 Jul 2019

One of the most notable trends in the solar PV market in the last couple of years has been the growth in bifacial solar panels.

The 2019 International Technology Roadmap for Photovoltaics (ITRPV) predicts that bifacial cells will increase their share of the solar PV market from around 15% in 2019 to 60% in 2029.

So, time to sit up and take notice. What are bifacial PV modules, and why are they set to dominate the market over the next 10 years?


Topics: Solar PV

Best Angle for Solar Panels in the UK and Beyond

Erica Charles · 03 May 2019

The best direction for a roof with solar panels is dead south. Except if you're in the Southern Hemisphere when you want it to be facing north - which is why solar panels are like bath water spiralling down the plug hole.

But few people in Guildford have a roof that faces exactly south. And few people in Guinea have a roof that faces exactly north. So the key question for many of us is: "How much solar generation do I lose if my panels don’t face exactly south?"


Topics: Solar PV

BIPV Facades: Improve Building ROI with Photovoltaic Curtain Walling

Erica Charles · 15 Feb 2019

Research indicates the market for curtain walling is growing at a healthy rate of around 6% per annum. (A curtain wall is the non-structural weather proof covering of a building, generally associated with large multi-storey buildings.) This rise is driven both by new build construction and by energy efficient refurbishments of existing buildings.

Standard curtain walling improves the thermal insulation of the building, leading to reduced HVAC costs and reduced heat loss. It also improves the aesthetic appearance of the building.

A photovoltaic curtain wall has the added benefit of generating electricity over the building’s life.

Whilst it costs a bit more than standard curtain walling, the incremental cost of a BIPV facade will typically be paid back within around five years.


Topics: BIPV, Solar PV

Solar Panel Shortages: Order Ahead to Secure Panels for your Projects

Erica Charles · 17 Jan 2019

If you have a requirement for Solar PV as part of any project in Q1 or Q2 this year, we recommend you place an order for the installation as soon as you can in order to secure stock, current low prices, and installation labour.

The overall trend in the solar PV industry is one of technological improvements (more Watts per 60 cell panel), and manufacturing improvements (lower prices), but in the first half of this year a perfect storm is brewing leading to limitations in supply, and the potential for increasing prices.

Three factors are at play:


Topics: Solar PV

Easy Roof Evolution: In Roof Solar with Velux Windows

Erica Charles · 07 Dec 2018

If you are building a new property or re-doing a roof and want to install solar PV, it makes sense to look at roof integrated solar panels.

There are a few systems on the market, for example Viridian Solar and GSE.  But one system in particular, Easy Roof Evolution, stands out if you want Velux® windows within the solar array.


Topics: In roof solar panels, Solar PV

Solar Panel Output Calculator: Commercial Solar PV

Erica Charles · 30 Nov 2018

Two or three weeks ago we launched a 'Back-of-Envelope' Solar PV Calculator.

You can access it here:

Go to solar calculator

I have been using the calculator to get a rough idea of what the returns from solar PV look like in a post-subsidy world, without bothering our Estimating team (who, as you can imagine, are pretty busy in the run up to the Feed-in Tariff closure on 31st March 2019).

Here's an example of what 75kWp of un-subsidised solar PV looks like, retro-fitted to a factory roof...


Topics: Solar PV, Calculator

Choosing an Electric Car Charger for a Commercial New Build

Erica Charles · 09 Jul 2018

If you are involved in electrical specifying, it’s only a matter of time before you are going to have to specify electric car chargers as standard on many of your commercial sites.

Whether you are installing a single commercial chargepoint, or a multi-site network, there are a few things you need to consider when choosing a charger brand and model.

We’ve written a 2 minute guide below:


Topics: EV charging

Solar Panel Bird-Proofing Without Voiding the Panel Warranty

Erica Charles · 11 Apr 2018

If you are in charge of specify or installing on-roof solar panels, you should consider installing solar panel protection to stop birds from nesting under the panels. 

Nesting birds cause problems for solar panels and increase the need for general building maintenance. 

Luckily the industry has now developed well-proven solutions for solar panel protection: solar mesh and solar bird spikes.


Topics: Maintenance, Solar PV

Electric Car Charging Points Installation: Focus on EVBox

Erica Charles · 16 Mar 2018

By 2020, a business with 100 employees can expect to have 10 employees with an electric car.

It is hardly surprising that we are gradually seeing the inclusion of EV charging points in new build specifications, both residential and commercial.

If you are needing to specify EV chargers in a project, what functionality should you look for, and which brand should you choose?


Topics: EV charging