SolarMax SM-3.6K-H1P and SM-5K-H1P are single phase hybrid inverters for 48 V lead-acid or lithium batteries (see the SolarMax datasheets). Faults show as an F number on the screen and in the Device Info page. The table below comes from SolarMax's user manual for these models. For any brand, our guide on reading inverter fault codes explains the basics.
What SolarMax F codes mean, in plain words
The inverter checks the grid, the panels, the battery and its own temperature all the time. When a reading goes outside its safe range, it stops or limits output and shows a code. Many codes clear by themselves once the cause goes away; the manual's first step for most of them is to wait and check again.
Where SolarMax faults come from
Grid side
F35, F42, F47, F48
Panel side
F20, F23, F24, F63
Battery and inside
F13, F18, F26, F56, F64
SolarMax SM-H1P error code table
| Code | What it means | Typical cause |
|---|---|---|
| F13 | Working mode change | The inverter changed its work mode; usually clears within a minute |
| F18 | AC over current (hardware) | Backup or home load above the inverter rating |
| F20 | DC over current (hardware) | Panel or battery connection |
| F23 | AC leakage current | Leakage on the panel or inverter cable, often after rain |
| F24 | DC insulation impedance failure | Panel wiring insulation or the earth connection |
| F26 | DC busbar unbalanced | Internal: often clears after a wait, call us if it repeats |
| F35 | No AC grid | Load-shedding, a tripped breaker or a loose grid connection |
| F42 | AC line low voltage | Low local voltage or loose AC cables |
| F47 | AC over frequency | Unstable supply or generator |
| F48 | AC lower frequency | Unstable supply or generator |
| F56 | DC busbar voltage too low | Battery deeply discharged |
| F63 | Arc fault | Panel cable or connector problem (detection is a US-market feature) |
| F64 | Heat sink high temperature | Hot room, blocked airflow or dust |
SolarMax safe owner checks
- Photograph the screen and note the date and time. The Device Info page lists recent alarm codes.
- During load-shedding, F35 (No AC grid) is normal. It clears when the supply returns.
- Check whether your main breaker or a voltage protector has tripped.
- For F18, switch off heavy loads on the backup output and see if the fault clears.
- For F56, let the battery charge from solar or the grid before running loads again.
- Keep the area around the inverter ventilated and free of dust. Never wash the inverter with water.
When to call an engineer
- F18, F20 or F26 faults that repeat after a restart.
- F23 or F24 (leakage or insulation), especially after rain or panel washing.
- F42, F47 or F48 that happen every day: we measure the supply at the inverter and check the AC cables.
- F63 (arc fault): switch off at the AC breaker and call us.
- F64 that comes back in normal room temperature.
To restart, follow our safe restart steps.
SolarMax service in Punjab
We service SolarMax hybrid inverters in Faisalabad, Lahore and across Punjab, including systems installed by other companies, as a paid visit.
Send us
A photo of the error and the Device Info page, your SolarMax model and serial number, and when it happens.