The Powerwall lithium battery system from Tesla Energy has made a big impact in the solar world and pushed home energy storage into the mainstream. The latest iteration in the Tesla home battery series is the new Powerwall+ (plus) which was first publicised in May 2021. The new Powerwall+ is essentially the Powerwall 2 battery system with an integrated solar inverter making it a complete all-in-one solar energy storage system. The Powerwall uses lithium NMC (Nickel-Manganese-Cobalt) battery cells developed in collaboration with Panasonic, which are similar to the Lithium NCA cells used in the Tesla electric vehicles.

It’s also the only battery to incorporate liquid cooling, which means it may out-perform and outlast many other batteries, especially in extreme climates.

With a 10-year warranty and building on experience from the durable Tesla electric vehicle batteries, the Powerwall appears to be a very well-engineered battery system and has so far proven to be a high-performing battery.

The Powerwall 2 platform with an integrated Tesla solar inverter to create a complete all-in-one system. While the storage capacity remains the same at 13.5kWh, the power rating has increased substantially to cater for dedicated off-grid and backup use. The power ratings are up from 5kW continuous and 7kW peak, to 7kW continuous and 9.6kW peak in off-grid mode. On-grid power ratings have also increased slightly to 5.8kW continuous and 7.6kW peak.

Backup Gateway

The Powerwall 2 cannot function as a backup power supply or UPS without the additional Backup Gateway. The new Backup Gateway 2 is around (US$1200) and functions as the household energy management system and communications hub. In the event of a blackout, it also isolates the backup circuits from the electricity grid and enables the system to function in off-grid mode. The gateway also provides advanced monitoring options and time-based controls.

The Tesla App

The Tesla app enables real-time monitoring of grid energy usage, battery state of charge and solar generation in a simple, easy to use interface. The app is common to all tesla products and provides a seamless interface between EV control, solar generation and energy storage.

The Tesla app provides 4 different Powerwall control modes

• Self-Powered Mode - Increases self-consumption of solar by storing excess generation.

• Time-Based Control - Prioritises energy storage or consumption based on your electricity usage tariffs to reduce bills and save money.

• Storm Watch - Automatically charges the Powerwall in the event of a major storm or blackout.

• Vehicle Charging During A Power Outage - Enables the Powerwall to Tesla EV’s to dynamically adjust the charge rate to prevent overloading the system during a power outage.