05·RB-SOLAR
Runbook — Solar production looks low
Before you assume something is wrong: compare this week to the same week last year, not to last month. In this climate, that one habit answers most of these questions.
956 N Noble Loop · Showing Edition · Rev A · Aug 2026
A 36-panel array in south-west Washington produces several times more in July than in December. That is not a fault, it is latitude and weather, and it is why a solar system is sized against a whole year rather than a good afternoon. So the first job is to decide whether you are looking at winter, or at a problem — and the Tesla app can tell you in about a minute.
First, check — in this order
- Open the Tesla app and look at the energy graph, not today’s number. Switch to the year view. Compare the current month with the same month a year ago. If the shape matches, the system is fine and the season is doing what seasons do.
- Is production actually zero, or just low? These are completely different problems. Low-but-present means weather, shading, soiling, or curtailment. Zero on a bright day means something is off — a breaker, an inverter, or a disconnect.
- Look out of the window. Overcast, fog, or wildfire smoke can cut output by most of its potential. Pacific Northwest smoke in late summer is a real and often-missed cause: a hazy orange sky is worth ten degrees of tilt in the wrong direction.
- Look at the roof. From the ground, with binoculars or a phone camera. Moss, needles, leaves, pollen film, bird mess, or snow across the bottom edge of a row. Panels shed rain well but this climate grows things on everything. Never climb up to check.
- Look at the trees. The garden has mature fruit trees and the neighborhood has grown since 2017. Shade that was not there five years ago is the most common slow decline in residential solar, and the graph gives it away: production that dips at the same time each afternoon and recovers.
- Check the batteries are not simply full. On a sunny day with the Powerwalls charged and the house using little, the system may deliberately throttle back production. Low numbers with a full battery and a happy app are normal behavior, not a fault.
- Look at the inverters on the exterior equipment wall. Two wall-mounted Delta string inverters sit above the Powerwalls, alongside the meters and the disconnects, on the outside of the garage’s north wall. Each has a status display. A dark screen or a lit Fault LED on one unit explains roughly half the array going missing. Exact inverter model still to gather.
- Check the disconnects and breakers. There is a clearly labeled rapid-shutdown switch for the PV system and an AC disconnect on that same wall, plus solar breakers in the panel. If someone switched one during other work, production goes to zero and stays there. Do not simply switch them back without reading the point below.
- Check the separate solar generation meter. The equipment wall carries a solar generation output meter as well as the utility meter. It is an independent second opinion on whether the array is producing, useful when the app and your expectations disagree.
Before you re-close a solar breaker or disconnect
Those switches exist so that firefighters and technicians can make the array safe. If one is open, find out why before closing it — somebody may have opened it deliberately for work in progress, or the system may have opened it because of a fault. Check the Tesla app for alerts first, and if there is any doubt, contact Tesla Energy support rather than switching it yourself. There is no homeowner-serviceable part inside an inverter or a rapid-shutdown box.
Symptom → cause → fix
| Symptom | Likely cause | What to do |
|---|---|---|
| Lower than last month, similar to this month last year | The season. Normal. | Nothing. Use the year-over-year view whenever the number surprises you. |
| Lower than the same period last year, by a lot | Soiling, new shading, or a partial fault. | Check the roof from the ground, check tree growth, then check both inverters. If those look fine, raise it with Tesla Energy support — they can see the array remotely. |
| Production drops out for part of the afternoon, every day | Shading from a tree, chimney, or neighboring structure. | Compare the timing across weeks. Trimming is the fix, and it is a landscaping job rather than a solar one. |
| Roughly half the expected production, consistently | One of the two inverters is offline, or one string has failed. | Look at both Delta inverter displays. This is the classic signature of a single inverter down, and it is a service call. |
| Zero production on a sunny day | Open breaker, open disconnect, rapid shutdown activated, or an inverter fault. | Check the app for alerts, then look at the equipment wall. Contact Tesla Energy support — do not start closing switches blind. |
| App shows no data at all | Monitoring offline, not production offline. | The system reports through the house network. See internet down. Production continues regardless; you have simply lost the view. |
| Good production, but the electricity bill went up | Consumption changed, or the utility’s net-metering arrangement changed. | This is a billing question, not a fault. Compare consumption in the app, and see the energy pages for how net metering works with Clark Public Utilities. |
| Production fine, Powerwalls not charging | A settings question — reserve, mode, or grid charging. | Check the operating mode and Backup Reserve in the app. See power outage for what those settings do. |
| Snow on the panels | Snow. It happens a few days a year here. | Wait. It slides off as the panels warm. Never climb up to sweep them — the risk is entirely one-sided. |
What “normal” looks like here
The Tesla app holds this array’s own production history, and a year of it is worth more than any rule of thumb: note the best day of each month, and after one full cycle the question “is this low?” becomes a lookup instead of a worry. Year-over-year is the only comparison that means anything with solar.
The array is 36 panels installed as part of the 2017 build, feeding a pair of wall-mounted string inverters and two Powerwalls through a Tesla gateway, with a separate solar generation output meter and a labeled PV rapid-shutdown disconnect on the exterior equipment wall. Panel and inverter models, the installing contractor, the interconnection agreement with Clark Public Utilities, and the production history are still to gather — including whether the system was installed by Tesla or by a third party, which determines which Tesla support path applies when it needs service.
Stop and call a pro when…
- Production is zero on a clear day, or an inverter shows a fault — Tesla Energy support through the Tesla app. They monitor the system remotely and will usually know more than you can see from the ground.
- You can see physical damage — a cracked panel, a hanging conduit, storm or animal damage — Tesla Energy support, and photograph it from the ground for your insurer.
- Anything on the equipment wall is scorched, buzzing, or hot — treat it as an electrical emergency: 911 if there is smoke, otherwise a licensed electrician experienced with PV and storage.
- The panels need cleaning or the roof needs work — a solar cleaning or roofing contractor who carries the right insurance. Not you, not a ladder, not a pressure washer.
- You need the array shut down for roof work — arrange it through Tesla or a qualified PV contractor. The rapid-shutdown switch is not a substitute for a proper isolation procedure.
Related pages
- Power outage — the solar keeps producing during an outage because it is paired with Powerwall, which is the whole point of the system.
- Breaker trips — for the solar and Powerwall breakers on the exterior panel.
- Electrical & Energy — the array, the inverters, the Powerwalls, and how net metering works here.
- Internet down — when the app shows nothing but the array is fine.
- Tesla — Service and Warranty (solar)
What Tesla covers and how to raise a service request. - Tesla — Best Practices During Power Outages
Includes how Powerwall recharges from solar when the grid is down. - Clark Public Utilities — Contact Us
For net-metering and interconnection questions on the billing side.