A 150Ah battery is one of the most popular choices for homes and small businesses facing regular power cuts—but the question everyone asks me is always the same: “How long will a 150Ah battery run 2 fans?”
As someone who works every day as a solar products manufacturer and exporter, dealing with inverter batteries, solar inverters, online UPS systems, EV chargers, lithium-ion batteries, and tubular batteries, I’ve answered this query more times than I can count.
So in this blog, I’m going to break it down for you in the simplest way possible. No complex engineering terms, no confusing formulas—just practical, real-world explanations based on years of hands-on experience. Whether you’re a homeowner trying to plan your backup or a business owner evaluating products for your customers, this guide will give you a clear picture of how a 150Ah battery performs when running two fans for long hours.
Understanding the Basics First
Before we calculate the backup time of a 150Ah battery for two fans, we need to understand a few basics. Don’t worry, I’ll keep it super simple.
Every electrical appliance consumes power (in watts).
What is Battery Capacity (Ah)?
A 150Ah battery means:
- It can supply 150 amperes for 1 hour, or
- 15 amperes for 10 hours, or
- 5 amperes for 30 hours
To convert this into stored energy:
12V × 150Ah = 1800 Wh (watt-hours)
But in real-life use, you cannot use 100% of the battery’s energy due to:
- Inverter losses
- Battery efficiency
- Heat
- Wiring losses
So we typically get about 80% usable capacity.
Usable energy ≈ 1440 Wh
Power Consumption of the Fans
Most ceiling fans consume between 50W to 90W, depending on:
- Motor type
- Brand
- Speed
- Efficiency
On average, a standard ceiling fan consumes 70W.
So two fans = 70W × 2 = 140W
This is the load your battery needs to handle.
Backup Time of 150Ah Battery for 2 Fans
Let’s use the simplest formula:
Backup Time = Usable Battery Capacity (Wh) ÷ Load (W)
Here:
- Battery gives approx. 1440 Wh
- Load is 140W
Backup Time = 1440 ÷ 140 ≈ 10.28 hours
So under normal conditions, a 150Ah battery can run 2 fans for 9.5 to 10.5 hours.
This is the most accurate practical estimate.
Why Backup Time May Increase or Decrease?
As a solar products manufacturer and exporter, I often explain that backup time depends on several real-world factors.
1. Fan Speed
High speed uses more power, reducing backup time.
2. Battery Age
New battery → Higher backup
Old battery → Lower backup
3. Battery Type
A high-quality tubular battery gives more stable backup than a low-grade flat plate battery.
4. Inverter Efficiency
A good inverter wastes less energy.
An inefficient inverter can reduce backup by up to 25%.
5. Temperature
Batteries perform best at normal room temperature.
Real-Life Backup Examples
Here are some real-world scenarios from field installations:
1. Two BLDC Fans (35W Each)
Total load = 70W
Backup = 1440 ÷ 70 ≈ 20+ hours
2. Two Normal Fans at Full Speed (80W Each)
Total load = 160W
Backup = 1440 ÷ 160 ≈ 9 hours
3. Mixed Speed Usage (One fan low, one high)
Total load ≈ 120W
Backup ≈ 12 hours
4. Old Battery (70% health)
Usable energy ≈ 1260 Wh
Backup = 1260 ÷ 140 ≈ 9 hours
Why Tubular Batteries Give Better Backup
We manufacture high-performance tubular batteries, and based on thousands of customer experiences, I can confidently say:
Tubular batteries are built for:
- Deep discharge
- Heavy load
- Long backup
- Better heat tolerance
This is why a 150Ah tubular battery performs much better than a normal battery.
How to Get Maximum Backup from Your 150Ah Battery
Here are simple habits that increase your backup without spending more:
- Use BLDC fans instead of normal fans
- Keep your inverter in a cool, ventilated place
- Avoid overloading
- Keep the battery water level in range (for lead-acid tubular batteries)
- Charge the battery fully regularly
- Use high-quality cables and inverter
Small habits create a big difference in backup hours.
Should You Choose a Solar Battery Instead?
Since we are also a solar products manufacturer, I recommend solar batteries if:
- Your area has long power cuts
- You want better battery life
- You plan to install a solar system later
Solar tubular batteries are optimized for solar charging, giving long-term performance.
Do Solar Panels Increase Backup Time?
Yes—if you pair your inverter battery with even a 330W–550W solar panel, your backup increases significantly because:
- Sunlight charges the battery
- Load shifts to the panel during the day
- Battery discharges slowly
Solar panels make the whole setup more cost-effective.
Final Practical Answer (Summary)
A 150Ah tubular battery, when connected to an efficient inverter, will run 2 standard fans for around 10 hours.
With BLDC fans, the same battery can give up to 20 hours.
Actual backup depends on:
- Fan wattage
- Inverter efficiency
- Battery age
- Temperature
- Load usage habits
Conclusion
A 150Ah battery is a reliable choice for running two fans for long hours during power cuts. When paired with a good inverter and efficient fans, you can easily achieve 9–12 hours of uninterrupted backup. As a solar products manufacturer, battery and inverter supplier, and exporter, we always recommend investing in a high-quality tubular battery for durability, performance, and long backup.
If you are a business owner, dealer, or importer evaluating high-performance batteries, inverters, or solar solutions—we can support you with premium products, export-quality assurance, and best pricing.
