Solar Inverter Not Turning On: What to Check
TL;DR
An inverter with no lights is usually not broken. The commonest causes are a tripped AC breaker, a grid outage, or simply too little light for it to start. Confirm supply on both the AC and DC sides before assuming failure, and never open the enclosure yourself.
An inverter showing no lights is usually not a dead inverter. Before assuming a replacement, work through the ordinary causes, because most of them are supply issues rather than failures.
The important safety line: never open the enclosure. Inverters hold dangerous voltages, including charge stored in capacitors that persists after everything is switched off. Opening the case also voids the warranty on essentially every unit sold.
The obvious causes, in order
1. It is night, or nearly. No light means no DC input means no operation. Many inverters go completely dark rather than showing a standby light. This is normal.
2. There is a grid outage. A grid-tied inverter requires the grid to be present. During a brownout it shuts down and displays nothing, even at midday in full sun. That is required behaviour, not a fault — see do solar panels work during a brownout.
3. The AC breaker has tripped. The inverter takes its own supply from your consumer unit. If that breaker is off, the unit is unpowered. Reset it once. If it trips again straight away, stop — it is protecting against something real.
4. The DC isolator is off. There is usually an isolator between the array and the inverter. If someone has switched it, or it was left off after maintenance, the inverter has no input.
5. Too little light to start. Inverters need a minimum DC voltage before they wake. On a heavily overcast morning, starting late is normal.
What the display is telling you
| Symptom | Most likely meaning |
|---|---|
| Completely blank, no LEDs | No AC supply — breaker or grid |
| Standby light only | Waiting for enough DC voltage from the array |
| Clicking or humming, no output | Failing a start-up check, often grid quality |
| Error code shown | A specific detected fault — note the exact code |
| Normal lights, low output | Not a start-up problem — see below |
If there is a code, write it down exactly. Codes are specific and looking one up in the manual or the manufacturer’s app usually identifies the problem in seconds — our Deye, Growatt and Solis error code tables cover the codes we could confirm against those manufacturers’ own manuals. “Grid voltage out of range” and “insulation fault” lead to entirely different conversations.
If it is producing but poorly
That is a different problem with a different diagnosis — shading, dirt, a dropped string, or seasonal weather. Work through why is my solar panel not working instead, which covers output faults rather than start-up faults.
When to call an electrician
Immediately, and without touching anything, if you find:
- Any burning smell or scorch marks at the inverter
- Water ingress into the enclosure
- A breaker that trips repeatedly on reset
- Damaged or exposed DC cabling
- Repeated failed start attempts with the same error code
Also call if the unit is simply unresponsive after you have confirmed AC supply is present and the DC isolator is on. At that point you have exhausted what can safely be checked from outside the box.
Heat is what kills inverters here
Inverters are commonly warranted 5-10 years — well short of the panels’ 25. They are the component most likely to need replacing partway through a system’s life, and in Philippine conditions heat is the main reason.
An inverter mounted on a west-facing wall in direct afternoon sun runs hot every day of its life. The same unit in shade with airflow around it lasts longer. If yours is badly sited, relocating it is far cheaper than replacing it early — worth raising at the next service visit.
The same logic applies to batteries, which are equally heat-sensitive and equally often installed somewhere convenient rather than somewhere cool.
Preventing the next one
- Keep the area around the inverter clear and ventilated
- Check the display or app weekly so you notice problems in days, not months — solar monitoring
- Note your normal daily output so you have a baseline to compare against
- Keep the installer’s contact and the warranty documents somewhere you can find them
Frequently asked questions
My inverter has no lights at all. Is it dead?
Usually not. No lights most often means no AC supply — a tripped breaker in your consumer unit, or a grid outage. A grid-tied inverter needs the grid present to operate, so it will show nothing during a brownout regardless of sunshine.
Why won't the inverter start in the morning?
Inverters need a minimum DC voltage from the panels before they wake up. On a very overcast morning it may take longer than usual. If it never starts on a clear day, that points at the DC side — the isolator, a string, or the array itself.
Is it normal for the inverter to switch off at night?
Yes, completely. With no light there is no DC input, so the inverter shuts down and restarts the next morning. Some units keep a small standby light; many show nothing at all.
Can I open the inverter to check inside?
No. Inverters carry dangerous voltages including stored charge in capacitors that persists after disconnection. Opening the case also voids the warranty on essentially every unit. This is an electrician's job without exception.
The inverter clicks or hums but doesn't produce. What now?
That usually means it is attempting to start and failing a check — often a grid quality issue or an insulation fault. Note any code it displays and report it. Repeated failed starts are worth escalating rather than ignoring.
How long should an inverter last?
Commonly 5-10 years under warranty, shorter than the 25-year life of the panels. Heat is the main thing that shortens it in Philippine conditions, so a shaded, ventilated mounting location genuinely extends its life.