Joules is a uniquely designed system, supplied as a fully integrated unit including batteries to store valuable renewable energy, inverter, Wattstor´s “iMP’ monitoring & control unit. the system comes pre-assembled in one cabinet to make it easy for you to install. The iMP control unit manages charging and discharging regimes according to your specific requirement. It can also monitor and control heating and cooling inside the building and any internet ready applicances to increase energy efficiency. The aim is to maximse the use of renewable energy.

Easy Installation

The Joules is built for fast, and easy installation, saving you time and money on expensive labour costs. It is prewired and preconfigured.


By maximizing the usage of your renewable energy, increasing efficiency and reducing the amount of used energy from the grid, the Joules will lower your annual energy bills and your carbon footprint.

Off-grid. Please!

With Joules, you will be always optimising your clean, green, solar energy and ensure your security of energy supply. Create your own rules.

iMP Smart Control

Wattstor´s intelligent management power unit has been created inhouse, allowing us to upgrade the software and parameters of the Joules with your future needs in mind.

Unique Solution:

Easy to install
No additional equipment and mounting needed
Pre-configured devices
Appliance control

Backup power supply:

Maximizing Renewable Energy usage
Minimizing operating costs
Reducing electricity bills and CO2 footprint
Off-grid ready
Emergency – stop button

Web interface:

Smart analysis - short and long-term predictions
Remote energy monitoring
Remote updating


This solution is for customers who already have a PV installation. Consumption from renewables can increase by as much as 99%, resulting in lower electric bills.

New Installation

It is the complete package solution to compliment your new solar installation. Perfect for your new renewable lifestyle.

Off-grid. Please!

Welcome to the off-grid era. A solution that is able to provide energy in a black-out situation. The change happens spontaneously, therefore the power cut is not noticeable.

Joules Options

Nominal inverter power 3 kVA3 kVA3 kVA5 kVA5 kVA
Usable battery capacity2.5 kWh5 kWh7.5 kWh5 kWh7.5 kWh
Nominal inverter output active power 2.4 kW2.4 kW2.4 kW4 kW4 kW
Battery charge current35 A35 A35 A70 A70 A

With a few details about your home, we can simulate how much a Wattstor system can save on your bills.

Wattstor is an award-winning expert in the design and installation of bespoke renewable energy systems for both domestic and commercial customers.