Homeowner Blog

PylonTech, Powervault, Powerwall 2... What's In the Warranty?

Erica Charles 12 Jun 2018

Following our analysis of Powervault 3 vs Powerwall 2, we had a couple of requests for a review of the SoFar / Pylontech residential battery storage system.

On the face of it, the SoFar / Pylontech combination offers good value, flexible sizing, and LFP (Lithium Ferro Phosphate) chemistry… so well worth consideration.

And that's before you appreciate the fun to be had when trying to summarise the essence of the different warranties: Pylontech vs Powerwall vs Powervault.

Here goes…

Read more

Topics: Solar PV battery storage, Tesla Solar Battery, Powervault 3, Pylontech

Powervault 3 vs Tesla Powerwall 2: Back of Envelope Economics

Erica Charles 11 May 2018

Last week our blog compared the chemistry of Powervault 3 (LFP) with the chemistry of Powerwall 2 (NMC).

The basic conclusion was that LFP means "double the life cycles, double the cost." As a rough guide, for someone installing Powervault 3 as part of a solar system (thus with a VAT rate of 5%), the rough costs are as follows:


Powervault 3

Tesla Powerwall 2

Storage Capacity:





Rough Installed Cost incl VAT @ 5%





Cost incl VAT @ 5% per kWh battery capacity






In fact in this case, the cost per kWh of LFP (Powervault 3) is more than double the cost per kWh of NMC (Powerwall 2).

But as we also said, with the 7.5kWh Powervault 3, you buy a minimum guaranteed level of 51,800 storage ‘slots’ upfront. With Powerwall 2, you only buy ’37,000’ slots upfront.

Powerwall 2 will pay for itself much more quickly than Powervault 3, but what does this mean for the overall lifetime economics...?

Read more

Topics: Solar PV battery storage, Tesla Solar Battery, Powervault 3

Powervault 3 vs Tesla Powerwall 2: It's All In The Chemistry

Erica Charles 30 Apr 2018

I have an abiding memory from secondary school of our chemistry teacher pressing ‘play’ on an old video cassette, and there, projected onto the screen at the front of the room, was a video made by what must have been a desperately struggling actor, dressed in yellow tights and a white coat, dancing on a lab bench and singing the 'Periodic Table song'.  

The video served two purposes:

  • it put us off chemistry;
  • it put us off acting.

At least it put me off acting. Kristin Scott Thomas attended the school a few years before I did, and clearly, it didn’t put her off acting (credits include Four Weddings and a Funeral, The English Patient, and most recently Winston Churchill’s long suffering wife in Darkest Hour ). No dancing on lab benches for her just to pay the bills.

To the video’s credit, more than a couple of decades later, I can still remember the first two rows of the Periodic Table. Of course I’ve never used the knowledge, until the advent of home battery storage.

Today, as the second in our series of blogs on Powervault 3, we are studying Lithium Ferro Phosphate (Powervault 3) vs  Lithiated Nickel Manganese Cobalt Oxide (Tesla Powerwall 2).

Don’t worry, ‘Studying’ is over-egging it. We’re looking at the differences from a home battery storage point of view...

Read more

Topics: Solar PV battery storage, Tesla Solar Battery, Powervault 3

Introducing Powervault 3: The Smartest Home Battery Storage System?

Erica Charles 27 Apr 2018

UK-based Powervault has recently launched Powervault 3, a home battery storage system which is designed to take full advantage of the revolution taking place in the UK electricity market.

Powervault totally ‘gets’ the future of electricity generation and storage in the UK and has built a battery system that can do everything you could ever think a homeowner would want it to be able to do….

Read more

Topics: Solar PV battery storage, Powervault 3

Tesla Time-of-Use goes live: is 2018 the year for time-of-use tariffs?

Henry Day 13 Apr 2018

Tesla recently confirmed that their eagerly anticipated Time-Based Control feature for Powerwall 2 is being rolled out to existing systems. 

We are now able to reveal the functionality available (and to confirm that as expected it's pretty comprehensive)...

Read more

Topics: Powerwall2, Tesla Solar Battery

Pigeon Seeks Room With A View: Solar Panel Bird Proofing

Erica Charles 05 Apr 2018

Solar panels offer a ready-made shelter for nesting under combined with a high vantage point from which to survey the surroundings.

If there’s such a thing as estate agency in bird world, and in particular pigeon world, it’s easy to envisage the blurb on the sale particulars for a nest under a well-located 4kW array.

Of course the pigeon’s gain is the system owner’s loss. 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.

Read more

Topics: Solar panel bird proofing, Solar panel protection

Which home car charging station? (and driving the 999 steps to heaven..)

Erica Charles 06 Mar 2018

Electric cars are coming of age.

There are 130,000 electric vehicles driving on UK roads, car manufacturers are investing heavily in the technology, and the charging infrastructure is gradually being rolled out.

What's more electric vehicles are already breaking all of the records. Whilst the gas guzzling Bugatti Chiron manages 0-60 in a leisurely 2.3 seconds, Japanese car maker Aspark has produced the electric Aspark Owl which does 0-60 in 1.921 seconds. Meanwhile the electric Range Rover Sport has recently climbed the ‘999 steps to heaven’ in Tianmen Mountain (watch the video from the start of minute 4 if you don't want to listen to the preamble). And of course, Elon Musk's Tesla  is nearly 5 million miles away from Earth, travelling, at the time of writing, at a speed of 7257 miles / hour, doubtless with Bowie's Starman still blaring out to announce man's latest visitation in space. Along with a load of our very best bacteria, apparently.

All very exciting. Back to the mainstream...

Driving an electric car costs around 3.5p per mile as opposed to 15p or more per mile for a petrol car.  If you drive 100 miles a week, you can save around £11.50 per week in fuel costs, to set against increased lease / finance costs of around £15 per week.

So for £3.50 a week you will be cutting out tailgate emissions, reducing pollution, and saving yourself from breathing in petrol fumes every time you fill up.

Now that you’ve been convinced to make your next car electric, you’ll need an EV charger.

Which charger?

Read more

Topics: zappi, Home car charging station, EVBox, EO Charging

Get Ready for the Sun: Solar Panel Maintenance and Cleaning

Erica Charles 23 Jan 2018

Believe it or not, spring is just around the corner.  And with it, the start of the sunny-but- not-so-hot season in which solar panels thrive.

Clean panels do better than dirty panels. And a well-maintained, serviced system does best of all.  

Which begs the question, how proactive should you be in looking after your solar system? What do other Spirit Energy customers do by way of servicing?

Read more

Topics: Solar panel maintenance

Are Solar Panels Worth It in 2018? Yes, Solar Power Costs From 5p/kWh!

Erica Charles 09 Jan 2018

This month saw a modest drop in the feed-in tariff. The tariff for a typical 0-10 kWp domestic system is now 3.93p per kWh, down from 4p per kWh before Christmas.

And well down from the heady days of 2010, when the feed-in tariff scheme was first launched and the subsidy was 43p per kWh.  So, are solar panels a good investment today?

Speaking purely from a financial view, the answer is a resounding yes.  Of course beyond the financial, there are many other environmental benefits to be gained from installing solar, installing residential battery storage, driving an electric vehicle etc. Not least because they all contribute directly or indirectly to tackling air pollution, which, we are told, is gradually destroying the nation's health.

Back to the financials. The solar subsidy may have fallen, but so has the cost of the technology.  Overall the cost of domestic solar electricity is now between 4p and 10p per kWh.  This is well below the 15p average domestic import cost from the grid (which, by the way increased by 7% in the last 12 months....)

Read more

Topics: Is Solar a Good Investment?

Save around 10% on your electricity bill with Voltage Optimisation

Erica Charles 11 Dec 2017

In line with CE and EU regulations, most of the UK’s electrical equipment is optimised to work at 220-230v. For historic reasons our electricity is supplied at an average of 242v but could be as high as 253v.

It is a little known fact that the more voltage you apply to an appliance the more energy it consumes – costing you more and shortening the life of the device.

By reducing your voltage supply to 230V or slightly below, it is possible to make a substantial energy saving (~ 12% reduction in the average home) and prolong the life of your electronic appliances.

Read more

Topics: Voltage Optimisation