Few things worry homeowners more than a solar system that works… only sometimes. Maybe the panels produce well in the morning but drop to zero midday. Maybe the inverter randomly shuts down and restarts. Maybe full strings go offline at certain times of the day. Or maybe the system performs perfectly on some days and terribly on others.
Intermittent solar system performance is one of the most confusing issues for Texas homeowners because the system appears fine at a glance — yet production is inconsistent, unreliable, and often unpredictable.
The monitoring app may not show obvious errors. Panels may look perfectly clean. And the inverter may seem like it's “trying” to work. But intermittent performance is always a sign of an underlying issue, usually related to wiring, shading, heat, or component failure.
This blog explains every major cause of intermittent solar performance, why these issues become more common in Texas, how to identify them, and what homeowners can do to fix them for good.
Why Your Solar System Works Sometimes and Fails Other Times
Intermittent performance usually means one thing:
Your system has a weak link that only fails under certain conditions.
This is what makes the issue tricky — problems may only appear when:
- The weather gets hot
- The sun hits at a certain angle
- AC units cycle on
- Clouds pass overhead
- Wind moves wiring
- Moisture settles into connectors
- Voltage fluctuates
Let’s break down the most common causes.
1. Loose or Failing Wiring Connections
Loose connectors are the number one cause of intermittent solar performance in Texas.
Why it happens:
- Heat expands and contracts wiring
- Roof movement loosens clips
- Wind vibrates conduit
- Wildlife chews insulation or tugs wires
- Installers didn’t fully seat MC4 connectors
Loose connectors can:
- Work in the morning
- Fail midday when temperatures rise
- Reconnect at night when temperatures cool
- Disconnect completely in storms
Signs this is the issue:
- Performance drops at the hottest part of the day
- Strings randomly appear and disappear
- Inverter restarts repeatedly
Loose wiring is dangerous because it can create arc faults — so this issue requires immediate attention.
2. Faulty Optimizers or Microinverters
Panel-level electronics often work fine until:
- They overheat
- They encounter shading
- Moisture enters the casing
- Internal components degrade
This causes:
- Panels dropping offline randomly
- Strings showing inconsistent voltage
- Daily production curves with sharp dips
- Production returning to normal the next day
In Texas heat, optimizers and microinverters are especially prone to intermittent failure.
3. Shading at Specific Times of Day
Many homeowners assume they have no shading — but shading changes seasonally and hourly.
Intermittent shading causes:
- Sudden performance drops
- Hot spots
- Uneven string output
- Voltage imbalances
- Afternoon or morning dips
If the system works perfectly during certain hours and poorly during others, shading is a likely cause.
4. Overheating: One of the Top Causes of Midday Shutdown
Texas roofs reach 140–170°F in summer. Panels, optimizers, and inverters get even hotter.
When wiring or electronics overheat:
- Inverters throttle output
- Optimizers shut down
- Strings disconnect
- Production plummets midday
Then as the roof cools off in the evening, everything “magically” starts working again.
Intermittent performance tied to heat is a major red flag.
5. Damaged or Chewed Wiring From Wildlife
Birds, rats, squirrels, and raccoons frequently cause:
- Partially cut wiring
- Exposed copper
- Damaged insulation
- Loose connections
- Broken connectors
Partial damage often creates intermittent performance:
- It works when wires touch
- It fails when wind shifts them
- It shorts during moisture buildup
- It fluctuates as temperatures rise
Wildlife damage always gets worse with time.
6. Moisture Intrusion After Storms
Moisture can enter:
- Conduit
- Panel backsheets
- Junction boxes
- Optimizer housings
- Rapid shutdown boxes
Moisture issues cause:
- Random inverter shutdowns
- Ground faults
- Performance drops only during humidity
- System failures after rain
Once moisture gets into electrical components, intermittent failure becomes common — especially in humid Texas summers.
7. Inverter Issues That Only Appear Under Load
An inverter may appear fine — until power demand increases.
Internal failing components often cause:
- Shutting off when AC units switch on
- Failing when voltage demand increases
- Midday restarts under heavy production
- Heat-related “derating”
These issues often track with:
- Time of day
- Weather
- Household power usage
An inverter that only works sometimes is usually nearing end-of-life or has internal board failures.
8. Grid Voltage Fluctuations
Texas has significant grid volatility due to:
- Heat waves
- Rolling demand
- Neighborhood surges
- Transformer overload
If grid voltage goes outside safe limits, the inverter shuts down — sometimes dozens of times in a single day.
This causes:
- Up-and-down production
- Random drops
- Inconsistent daily graphs
- Frequent restarts
Utility companies call this “normal,” but homeowners experience it as frustrating intermittent solar performance.
9. Poor Installation Quality
Systems with installation mistakes often show:
- Voltage mismatch
- Bad polarity connections
- Miswired strings
- Loose grounding
- Uneven tilt causing odd shadows
- Improper rapid shutdown wiring
These issues create intermittent performance from day one — even if the panels look fine.
10. Monitoring App Errors Masking Real Problems
Sometimes the issue is performance.
Other times the issue is monitoring.
Monitoring errors can make the system appear intermittent even when the problem is electrical.
Apps often:
- Miss data points
- Show late data
- Show partial string readings
- Drop communication
- Freeze production numbers
This creates the illusion of intermittent performance.
Signs Your Intermittent Solar Issue Needs Immediate Attention
If you notice any of these signs, the issue is serious:
1. Inverter repeatedly restarts
This indicates electrical imbalance or wiring failure.
2. Sudden dips during full sunshine
Not normal — shading or wiring issue.
3. Panels go offline randomly
Likely optimizer or wiring failure.
4. System shuts down midday
Heat or inverter stress.
5. Bill increases even when app shows production
System may not be sending power to your home.
6. Production drops only after storms
Moisture intrusion or loose connectors.
Intermittent issues don’t fix themselves — they get worse.
How Texas Homeowners Can Fix Intermittent Solar Issues
Here’s the correct approach to solving intermittent performance problems.
1. Schedule a Full Solar Maintenance & Diagnostic Service
A full diagnostic reveals:
- Wiring failures
- Loose connectors
- Voltage imbalance
- Damaged conduit
- Optimizer failures
- Microinverter burnout
- Inverter stress
- Grounding issues
This is the most accurate way to identify intermittent issues.
2. Professional Solar Panel Cleaning
Dirt, pollen, and debris can:
- Increase heat
- Exaggerate shading
- Cause voltage inconsistencies
- Create temporary panel hotspots
Clean panels improve consistency.
3. Inspect Wiring Under the Array
Most intermittent issues come from wiring hidden under panels — where homeowners cannot see.
Inspection reveals:
- Chewed wiring
- Moisture damage
- Loose connectors
- Conduit separation
- Heat damage
This step is essential.
4. Verify Inverter Logs and Monitoring Accuracy
Technicians can:
- Read inverter logs
- Check fault history
- Confirm communication
- Reset firmware
- Reconnect Wi-Fi
This identifies the true cause of intermittent data.
When a Solar Detach & Reset Is Required
A Solar Detach & Reset (D&R) is the most effective solution when:
- Wiring under the array is failing
- Moisture intrusion is widespread
- Wildlife damage is severe
- Connectors are corroded
- Panels have shifted
- Multiple strings show intermittent behavior
A D&R provides full access to hidden components and resets the entire system for stable, reliable performance.
