Solar Inverter Overload — Causes and How to Fix It
An overload occurs when the power demanded by your home exceeds the inverter's rated output. In the UAE, this commonly happens when air conditioning, water heaters, and kitchen appliances start simultaneously. Understanding and preventing overloads protects your inverter and ensures uninterrupted power.
What Causes Inverter Overload?
- Too many appliances running simultaneously: Starting an AC unit while the oven and water heater are running can easily exceed an 8 kW inverter's capacity
- Motor startup surges: Air conditioners, refrigerators, and pumps draw 3-5x their rated power for 1-2 seconds during startup
- Undersized inverter: The inverter was sized for normal load but cannot handle peak demand
- Battery backup mode: During grid outage, if all loads are on backup, total draw may exceed inverter capacity
How to Fix an Overload
Immediate Steps
- Turn off non-essential appliances (oven, water heater, dryer)
- Wait 60 seconds for the inverter to reset
- Turn on appliances one at a time, spacing startups by 30 seconds
Permanent Solutions
- Stagger heavy loads: Use timers so the water heater and AC do not start simultaneously
- Configure essential loads: On Deye hybrid inverters, programme which circuits receive backup power to limit peak demand during outages
- Upgrade inverter size: If overloads are frequent, consider upgrading from SUN-8K to SUN-10K or SUN-12K
- Add soft starters: Install soft starters on AC units to reduce startup surge current by 60-70%
Deye Overload Specifications
| Model | Rated Power | Peak Power (10s) | Overload Shutdown |
|---|---|---|---|
| SUN-5K | 5,000W | 10,000W | 110% for 60s |
| SUN-8K | 8,000W | 16,000W | 110% for 60s |
| SUN-10K | 10,000W | 20,000W | 110% for 60s |
| SUN-12K | 12,000W | 24,000W | 110% for 60s |
Deye inverters handle short overloads (up to 200% for 10 seconds) to accommodate motor startup surges. Sustained overloads above 110% trigger shutdown after 60 seconds.
Frequently Asked Questions
Why does my solar inverter keep showing overload?
The most common cause in UAE homes is running air conditioning, water heater, and kitchen appliances simultaneously. Motor startup surges from AC units draw 3-5x their rated power. Space out heavy appliance startups by 30 seconds or consider upgrading to a larger inverter.
Can a Deye inverter handle AC startup surge?
Yes. Deye inverters handle up to 200% rated power for 10 seconds, which covers most AC unit startup surges. A Deye SUN-8K can handle 16,000W peak. If your AC startup still triggers overload, add a soft starter to reduce surge current by 60-70%.
Should I upgrade my inverter if it keeps overloading?
If overloads happen regularly despite staggering loads, upgrading is recommended. Moving from a SUN-8K (8 kW) to a SUN-10K (10 kW) or SUN-12K (12 kW) provides 25-50% more headroom. The cost difference is AED 1,000-2,000.
