How to Know If Your Inverter Is Overloaded (Complete Guide for Beginners and Installers)
When your inverter is overloaded, it can shutdown suddenly, trip frequently, damage internal components, or even reduce battery lifespan. Unfortunately, many homeowners don’t know the warning signs until the inverter completely fails — which can be expensive to repair.
This guide explains how to identify overload, what causes it, and how to fix it permanently.
What Does Overload Mean on an Inverter?
Your inverter is overloaded when the total power consumed by the appliances connected to it is greater than the inverter’s rated output capacity.
Example:
A 1.5kVA inverter (≈ 1200W) cannot run:
- Freezer (250W)
- TV (120W)
- Fan (80W)
- Iron (1000W)
Total = 1,450W → Overload!
Common Signs Your Inverter Is Overloaded
1. Inverter Beeping Continuously
Most inverters produce a continuous or rapid beep whenever the load is too much.
If the beeping stops only when you switch off some appliances, you’re overloaded.
2. Inverter Shuts Down Suddenly
If your inverter switches off by itself while appliances are running, especially when heavy loads start up, that is a classic overload symptom.
Happens mostly when you turn on:
- Freezers
- Pump machines
- Blenders
- AC units
- Microwaves
These appliances have startup surge, which increases load temporarily.
3. Display Shows “Overload,” “OL,” or “Load High”
Modern inverters (Luminous, Sukam, Synergy, Prag, Growatt, Felicity, Deye) usually show overload messages like:
- OL
- Error 02
- Overload Shutdown
- Load High
If you see these messages, the inverter is warning you.
4. Fans Inside the Inverter Running Loud
When struggling to manage too much load, your inverter’s cooling fan becomes unusually loud.
This is the inverter trying to prevent overheating.
5. Burning Smell or Excessive Heat
If your inverter or cables smell like burning plastic or feel unusually hot, shut it down immediately.
This is an emergency overload sign and can lead to:
- Melted cables
- Fire hazard
- Damaged MOSFETs
- Short circuit
6. Battery Voltage Drops Very Fast
An overloaded inverter will drain your batteries quickly.
Example: If your 24V system drops from 25V to 23V in less than 5 minutes, your load is too much.
Fast voltage drop = overload + battery strain.
Why Inverters Get Overloaded
1. Too Many Appliances Connected
This is the most common reason. If you add more devices than your inverter can handle, it will overload.
2. High Surge Appliances
Some devices draw 2x–4x their normal running power at startup.
Examples of high-surge appliances:
- Freezers
- AC units
- Pump machines
- Blenders
- Microwaves
3. Wrong Inverter Size
Many people install small inverters for heavy loads because of poor sizing advice.
Example:
Trying to run AC on a 1.5kVA or 2kVA inverter will always cause overload.
4. Undersized Batteries
If the battery bank cannot support the current the inverter needs, the system overloads.
Example:
Running a 3.5kVA inverter on only one 200Ah battery is a recipe for overload.
5. Undersized Cables
Small cables heat up and restrict current flow, causing artificial overload signals.
If your inverter uses:
- 24V → use at least 25mm–35mm cable
- 48V → use 16mm–25mm cable
How to Prevent Your Inverter From Overloading
1. Know Your Inverter Capacity
Example (approximate usable watt output):
| Inverter Size | Usable Watts |
|---|---|
| 1.5kVA | 1,200W |
| 2.5kVA | 2,000W |
| 3.5kVA | 2,800W |
| 5kVA | 4,000W |
| 10kVA | 8,000W |
Always run 70% of max capacity for long-term use.
2. Don’t Run All Appliances at the Same Time
Switch off heavy loads during peak usage.
Example:
If you’re ironing, turn off freezer and AC during ironing.
3. Install a Bigger Inverter
If overload happens regularly, your inverter is too small.
Upgrade if you want to use:
- AC
- Pump
- Multiple freezers
- Heating appliances
4. Use Energy-Efficient Appliances
Replace old freezers or ACs with:
- Inverter ACs
- Low-watt freezers
- LED TVs
- BLDC fans
Energy-efficient appliances reduce load by 40–70%.
5. Increase Your Battery Bank
More batteries means your inverter draws current comfortably.
Example:
For 3.5kVA inverter → minimum 2–4 batteries (24V or 48V)
For 5kVA inverter → minimum 4 batteries (48V)
6. Install Proper Circuit Breakers
If the wrong breaker size is used, the inverter will interpret the resistance as overload.
Use:
- 80A–200A DC breaker for batteries
- Proper AC breaker for output load
How to Know the Exact Load on Your Inverter
Use a Power Meter / Energy Monitor (₦6,000 – ₦15,000).
Plug your appliances into it and check:
- Running watts
- Surge watts
- Total load
This prevents overloading and helps you size your solar system correctly.
Final Thoughts
An overloaded inverter is one of the major causes of inverter failure. The good news is that with the right checks—like monitoring load, using correct cables, avoiding high-surge appliances, and using proper breaker sizes—you can prevent overload completely.
