Powerwall 3 diagnostics
Per-unit capacity, degradation and solar strings for Powerwall 3, read through Tesla’s cloud. No Powerwall Wi-Fi to join and no gateway password to find.
What SolDial shows
Every Powerwall 3 gets its own card in Powerwall Devices: rated capacity (13.5 kWh), the full-charge capacity the battery reports today, degradation against the rating, state of charge, and for the leader its AC power, solar input and grid status. Expansion packs — the add-on batteries that have no inverter of their own — appear as their own cards with their own capacity and degradation, so a pack that is ageing faster than its siblings stands out.
Solar String Detail lists every string on the leader’s built-in inverter with live voltage, current and watts. Idle inputs are shown rather than hidden: a string sitting at 0 while its neighbours produce is exactly the signal of a shaded, disconnected or failing string.
How the data reaches SolDial
SolDial Pro asks for these diagnostics through Tesla’s cloud connection to your system — the same link the Tesla app uses — so they work away from home and in the web dashboard. SolDial refreshes them on its own every few hours and again when you open Devices or tap Refresh; the Last Synced line is the time Tesla last answered.
There is no Powerwall Wi-Fi network to join, no QR code to find behind a cover and no gateway password. If SolDial asks you to pair your Powerwall first, that is a one-time approval inside the Tesla app — see Pairing your Powerwall — and nothing physical.
Leader, expansions and followers
A Powerwall 3 system has one leader unit. Up to three Expansion packs can hang off each Powerwall 3; they add storage but have no inverter and no solar inputs. Any additional full Powerwall 3 is a follower, with its own inverter and its own strings.
Tesla reports battery data for every unit, so capacity and degradation appear for the leader, the expansion packs and the followers alike. Solar strings are different: Tesla’s cloud reports strings for the leader’s inverter only. A follower inverter is still listed in Solar String Detail, with its total output estimated as your site’s solar minus the leader’s strings (the line is marked estimated), but its individual strings are not available. If a separate solar inverter is also on the site, its output lands in that same estimate.
Why follower strings are not shown
String readings live on each inverter. For the leader, Tesla’s cloud passes them through; for followers it does not, and that holds for any app that reads diagnostics this way. The only way to read a follower’s strings today is a direct connection to the leader Powerwall’s own Wi-Fi network, using the Wi-Fi password printed on a QR code behind the unit’s cover.
SolDial does not ask you to do that. It means removing a cover that should only come off for service, taking your phone off your home network, and losing internet while connected — for a reading that goes stale the moment you disconnect. The estimated line answers the question that matters most on a two-unit system: whether the second inverter is producing at all. A dead or disconnected follower shows up as a remainder stuck near zero while the leader’s strings are producing.
Reading the numbers
Degradation is today’s full-charge capacity measured against the 13.5 kWh rating. A few percent in the first year is normal; what matters is the trend, and that units in the same system track each other closely.
Strings. Inputs with nothing wired to them read no input. UK and Australian Powerwall 3 units have three MPPT inputs that the firmware reports as six half-channels; SolDial folds each pair back into one string, so those systems show three strings named A+B, C+D and E+F.
Powerwall+ and Powerwall 2 systems show the same per-unit cards; see Powerwall devices & health and Solar & per-string detail.