Solar + Battery Health Check: 7 Signs Your System Isnt Performing
Published by C&T Smart Energy · April 2026
Most solar systems dont fail they quietly underperform. Thats what makes it expensive: you still have panels on the roof, but youre not getting the savings you expected.
This is a simple, plain-English health check you can do using your monitoring app and a few quick observations. If anything looks off, youll know what to ask and what a competent installer should check.
Before you start
- Pick a reliably bright day (not necessarily hot, just clear).
- Open your solar/battery app and find Today generation and battery charge/discharge.
- If youve got a smart meter or tariff app, have it open too optional but helpful.
1) Your generation graph looks flat on a sunny day
On a clear day, your generation should rise through the morning, peak around midday, then taper off. If its flat or capped early, it can indicate inverter limiting, shading, or a configuration issue.
What to ask your installer
- Is the inverter correctly sized for the array?
- Are there any export limits set by the DNO (and are they correct)?
- Can you show me the string voltages and any fault history?
2) Your battery rarely charges above 60 80%
Some systems are set up with conservative charge limits to protect battery life thats fine. But if youre consistently not reaching a high state of charge on good solar days, its worth checking settings and battery health.
3) Youre exporting lots of solar and still buying grid power in the evening
This is the classic battery not doing its job scenario. It can be caused by incorrect operating mode, time schedules, or a CT clamp / metering issue.
Quick check
In your app, look for Self-consumption or Home usage . If export is high during the day and import is high at 5 10pm, your battery strategy probably needs adjusting.
4) The app shows weird numbers (or doesnt match your smart meter)
Monitoring relies on correct metering. If CT clamps are reversed, placed incorrectly, or not commissioned properly, the system can make bad decisions and the app can mislead you.
5) Your savings feel good in summer but disappear in winter
Some seasonal drop is normal winter generation is lower. But if winter performance feels pointless , it may be because the system wasnt designed around your usage pattern, or the battery is too small for evening demand.
6) Youre getting repeated inverter alerts or dropouts
Dont ignore alerts. Grid overvoltage, arc faults, insulation resistance issues, or communication errors can all reduce output. A good installer should be able to pull logs and explain whats happening in plain English.
7) Your system was installed years ago and never had a proper handover
A surprising number of systems are left in default settings. A proper handover should include: operating modes explained, schedules set, export strategy discussed, and monitoring confirmed.
A simple next step
If you think your system is underperforming, the fastest way to get clarity is a structured review:
- Check monitoring and metering are correct
- Confirm export limits and inverter settings
- Review battery mode and schedules against your usage
- Identify whether the issue is design, settings, or a fault
Want a system designed properly from day one?
If youre planning solar or battery storage, well size it around your home and your usage with clear assumptions, proper commissioning, and aftercare.