Battery Energy Storage System Victron Multiplus-II 15000 and US5000 Pylontech – DIY Installation
Voltacon and Gave Electro: Official UK Distributors of Innovative Electrical Solutions
January 16, 2025
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BESS (Battery Energy Storage System) – Domestic Installation 40kWh – Off-Grid Operation with Grid Backup
We would vote for this installation as the best DIY project of the year 2025! This project showcases what an installer can achieve by carefully reading product manuals, watching approved instructional videos online, and, most importantly, having a passion for their work.
Our customer, who prefers to remain anonymous (understandably so, as many would like to replicate his concept and meticulous installation procedures), has generously provided us with all the images of his project. The entire bill of materials was supplied by Voltacon Solar. At the end of this blog, you will find the shopping list.
The property is connected to the national grid via a standard 100A single-phase power supply, like most homes in the UK. The homeowner uses Octopus as their electricity supplier. The house is also interconnected with the public grid and an external diesel generator, though the generator is only a backup solution. The inverter will prioritise battery storage but can draw energy from the grid when the batteries are depleted or when a low-cost tariff is available (typically between 12:30 AM and 5:30 AM).
The inverter is powerful enough to handle even the most demanding loads in the property. At any given time, the total power consumption will not exceed 15,000 watts, which is already an overestimation for a typical family home—but better to play it safe!
Victron BESS installed beside the ground source heat pump in the integral garage
Single-Line (simplified) BESS Circuit Diagram
Incoming AC Mains wiring, transfer switches and consumer units
Victron MultiPlus Inverter/Charger, Inverter fused AC supply isolator, Cerbo GX MK2 communication unit and GX50 display panel
Battery rack with eight PylonTech US5000 batteries, Victron Lynx Distributor and DC isolation switch,
(shown with protective grille removed)
Victron Lynx Distributor showing battery fuses, (with cover removed) and battery isolator
‘Zero Flame’ fire retardant solution
Victron MultiPlus configuration using a PC and MK3 to USB interface unit
VRM Dashboard ‘Overview’ Display 26 Jan 2025
VRM ESS ‘Scheduled Charge Levels’ Settings Page
VRM ‘Advanced’ Data Display for 25 Jan 2025
VRM ‘Dashboard’ showing Consumption and Battery Data for 25 Jan 2025
Octopus website showing KWh Consumption and Cost Data for 25 Jan 2025
Bill of Material – Hybrid Energy Storage System
The system can be configured to work from 5kW to 45kW in single or three phase system
