Powerwall Diagnostics

Introduction

Netzero provides access to diagnostic data for both Powerwall 2 and Powerwall 3 systems. This data is not available in the Tesla app. Diagnostics include battery capacity and degradation tracking, as well as solar string production (solar output broken down by individual strings of panels). These diagnostics can help you monitor system health, track performance over time, and identify potential production issues.

Diagnostic data is displayed on the Devices screen: tap a Powerwall card under Overview for capacity details, and open the Solar tab for string-level data. You can also download all diagnostic data with the Download Diagnostics button at the bottom of the Overview tab. Diagnostics are collected through Tesla’s cloud connection to the system, so they work away from home and in the web app. No local connection or password is needed. Diagnostics require a Netzero subscription.

Diagnostic Data

Powerwall Capacity

Like all lithium-ion batteries, the Powerwall’s usable capacity declines gradually over time. Netzero allows you to track this degradation so you can compare it against expectations or warranty terms. For warranty details, see Tesla’s documentation.

We have published analyses based on this data:

• Analysis of Powerwall Battery Retention
• Analysis of Powerwall Battery Retention - Part 2

Other Powerwall Data

The Powerwall card also shows, per Powerwall:

• Battery pack temperature range (minimum and maximum across the pack).
• Round-trip efficiency: the share of energy charged into the Powerwall that comes back out.
• Lifetime energy charged and discharged.
• Whether a calibration or a controlled discharge is in progress (see Health Monitoring).

The Alerts tab lists the diagnostic codes the system itself has reported in the last 3 days. See System alerts.

String-Level Data

String-level data shows the current, voltage, and power for each string of solar panels connected to your Powerwall+ or Powerwall 3. This allows you to pinpoint underperforming strings and investigate potential production issues.

For guidance on how to interpret string-level readings, see Diagnosing Solar Production Issues.

Notes:

• The UK and Australian versions of the Powerwall 3 have 3 MPPT (Maximum Power Point Tracking) ports, while the US version has 6 MPPT ports.
• Despite having only 3 MPPT ports, the 3-MPPT versions still report data for 6 strings in the diagnostics view (it appears that each MPPT port is internally split into two parallel ports).
• To determine the output of each of the 3 strings on a 3-MPPT system, sum the readings for the paired ports: 1+2, 3+4, and 5+6.

Powerwall 3: Leader/Follower Issue

In Powerwall 3 systems with a follower Powerwall 3 (additional Powerwall 3 units that are not expansion packs), string-level data is only available for the first (leader) Powerwall 3 inverter. Battery capacity is reported for every Powerwall. To get string data for the follower inverters, use legacy diagnostics to connect directly to the leader battery over its Wi-Fi network (using the Switch to legacy Monitoring link at the bottom of the Devices screen). See Powerwall 3 Legacy Diagnostics for instructions on connecting via the TeslaPW Wi-Fi network.