Solar App Says Offline or Shows an Alert? What It Means for Production, From LA Monitoring Data
An offline app usually does not mean the panels stopped. On a home system the panels and inverters make power on their own; the monitoring link is a separate piece, most often on the household Wi-Fi, and the gateway saves readings while the link is down and uploads them when it returns. In 814 system-years of daily data from 210 rooftop systems, most gaps were short: 229 of 360 lasted a week or less. The few long ones are what matter: gaps of more than a month made up 87% of all missing days, and a real fault inside such a stretch goes unnoticed until the bill.
How long gaps in monitoring data last
210 Enphase systems with a year or more of daily data, 814 system-years.
| Gap length | Gaps | Missing days | Share of all missing days |
|---|---|---|---|
| 1 day | 107 | 107 | 1% |
| 2–7 days | 122 | 431 | 3% |
| 8–30 days | 70 | 1,107 | 9% |
| 31–90 days | 41 | 2,271 | 18% |
| over 90 days | 20 | 8,405 | 68% |
| A gap is a run of days with no production recorded between a system’s first and last day of data. Data a gateway uploaded after reconnecting are included. March 8, 2026, a known recording fault, is skipped. | |||
https://cali-energy.com/research/solar-monitoring-offline-alerts-los-angeles. Aggregated data are free to use under CC BY 4.0 with a link to this page.Most gaps are short. Across 814 system-years there were 360 gaps, about one every two years per system, and the median lasted 4 days. But the few long gaps carry the weight: 61 gaps of more than a month account for 87% of every missing day, and 93 systems had at least one gap of eight days or more.
Losing the connection does not lose the data at first. Enphase says that when a system goes offline the gateway saves its data locally and, once reconnected, uploads it, which can take up to an hour for each day it was offline (Enphase support, “Understanding the Data Uploading notification”). The longer the silence, the longer the catch-up, and the more a real problem in between depends on someone noticing the bill.
A missing day can be lost data or lost production. Some are real outages — a tripped breaker, a failed microinverter, a grid outage, during which a grid-tied system without backup shuts down by design. A system that is switched off before the utility’s permission to operate is silent on purpose; see silent by design.
What SolarEdge alerts say
442 alerts on 72 of 94 SolarEdge sites since 2021.
| Alert | Code | Alerts | Sites | Typical duration |
|---|---|---|---|---|
| Site not communicating | SITE_COMMUNICATION_FAULT | 118 | 49 | 47 hours |
| Inverter production below expected | INVERTER_BELOW_THRESHOLD_GENERAL | 114 | 29 | 4 hours |
| Panel optimizer not communicating | PANEL_COMMUNICATION_FAULT | 69 | 5 | 60 hours |
| Inverter not communicating | INVERTER_COMMUNICATION_FAULT | 37 | 9 | 8 hours |
| Inverter production below expected (error code) | INVERTER_BELOW_THRESHOLD_ERROR | 31 | 1 | 1 hour |
| Voltage mismatch | VOLTAGE_MISMATCH | 28 | 5 | 16 days |
| Inverter below expected (DC isolation) | INVERTER_BELOW_THRESHOLD_DC_ISOLATION | 22 | 4 | 3 hours |
| Inverter below expected (off) | INVERTER_BELOW_THRESHOLD_OFF | 5 | 2 | under an hour |
| Grid voltage out of range | GRID_VOLTAGE | 4 | 3 | 10 hours |
| Meter not communicating | METER_COMMUNICATION_FAULT | 3 | 2 | 2 hours |
| Typical duration: median time from first trigger to close. | ||||
Communication alerts were the most common: “site not communicating” came up 118 times on 49 sites and typically cleared in about 2 days. Production alerts were the next largest group: “inverter production below expected” fired 114 times on 29 sites and usually cleared within 4 hours, often after a cloudy morning or a short grid disturbance. An alert that stays open for weeks is the one to act on. When an inverter does fail, how long the repair takes and how much output it restores is measured in what an inverter failure costs.
Cellular connections and their end dates
A cellular gateway does not depend on the house network, which makes it the more reliable link. But it has its own clock: 41 gateways in our fleet carry a cellular modem, and their data plans end between 2026 and 2031, 30 of them by 2028. Networks retire too: when carriers switched off 3G in 2022, older modems went dark while the arrays kept producing. Two of our case studies show both sides: monitoring that does not need your Wi-Fi and when the network went away.
If your app says offline
Check the network first
A new router, provider or Wi-Fi password is the most common cause. Reconnect the gateway to the new network from the manufacturer’s app.
Check power to the gateway
A tripped breaker or an unplugged gateway silences monitoring; a tripped solar breaker also stops production.
Read the utility meter
If the meter still shows exports on sunny days, the panels are working and only the reporting is down.
Do not wait months
A short gap is routine. A silence of more than a few weeks is when to call, because a real fault can hide inside it.
How to read the app itself: solar monitoring apps. If production looks low rather than missing: solar not producing. One panel lower than the rest: panel-by-panel data.
Methodology
- Gaps
- Runs of days with no production recorded in each system’s daily data, between its first and last day with production, for 210 Enphase systems with at least a year of data. Data that a reconnected gateway uploaded later are included.
- Alerts
- SolarEdge alerts from the monitoring account for 94 sites (sites we service but did not install, and sites expanded mid-period, are left out), with first trigger, last trigger and close date. Names are SolarEdge’s alert codes; the plain-English labels are ours.
- Cellular plans
- End dates of the data plans recorded for gateways with a cellular modem.
- Limits
- The monitoring record cannot separate lost data from lost production.
Sources: Cali Energy monitoring fleet (Enphase Enlighten and SolarEdge monitoring); Enphase support, “Understanding the Data Uploading notification in the Enphase App” (December 2024).
Frequently asked questions
My solar app says offline. Are my panels still producing?
Usually yes. The panels and inverters produce on their own; only the reporting has stopped. Check that the utility meter still shows exports on a sunny day, then reconnect the gateway to your network.
How long do gaps in solar monitoring usually last?
Most are short: in our data the median gap lasted 4 days and 64% lasted a week or less. Gaps of more than a month are rare but account for most missing days.
Do I lose my production data when the gateway is offline?
Not right away. Enphase says the gateway saves data while offline and uploads it after reconnecting, up to about an hour per day offline. Days that never come back stay missing in the app.
Why did my solar monitoring stop after I changed my internet?
Because the gateway is still looking for the old network. Reconnecting the gateway to the new router or password usually restores reporting.
What does a SolarEdge site communication fault mean?
The site stopped sending data to SolarEdge’s cloud. In our data these alerts typically cleared in about 2 days; if one stays open for weeks, check the inverter’s connection.
More research
Next steps
Monitoring silent, or output looks wrong?
Prepared by Cali Energy, October 15, 2026. Figures describe systems in our monitoring fleet and are not a guarantee of what any specific roof will produce; orientation, tilt, shade, equipment and weather change results. Not engineering, financial or utility advice. See our Content Disclaimer.