Deye F48: AC Under Frequency
F48 is the mirror image of F47: the grid frequency dropped below the allowed range, so the inverter disconnected to follow grid-protection rules. Frequency is set by the utility, so F48 is almost always a grid-side event that clears by itself once the grid recovers.
What usually causes F48
- A short grid frequency dip on the utility side.
- A weak or overloaded grid, where frequency sags under heavy demand.
- Running off a generator that bogs down under load.
The safe fix, step by step
- Wait for it to clear. The inverter reconnects automatically once the frequency is back in range. A brief, occasional F48 is normal.
- Notice the frequency. Rare is fine; frequent F48 suggests an unstable or overloaded supply.
- On a generator, make sure it isn't overloaded and is tuned for stable output.
- For persistent F48, contact your installer or utility about grid stability.
Related Deye codes
FAQ
Is F48 a problem with my inverter?
Usually no. F48 reports a grid-side frequency dip the inverter must react to. It clears on its own; only frequent events suggest a supply problem worth raising with your installer or utility.
Why do F47 and F48 both show up sometimes?
An unstable grid can swing both above and below the frequency limits, so you may see both over-frequency (F47) and under-frequency (F48) on a shaky supply.
Sources
- Deye Hybrid Inverter User Manual (F48 = "AC lower frequency"; frequency must stay within the specified range).
- Deye dealer technical references for grid-frequency codes.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off". This guide covers observation only. Grid and generator issues should be handled by your installer, utility, or a qualified technician.