In today’s video, we’re going to learn how to power a laptop and other 12-volt appliances directly from a solar panel without using a battery, which is often the most expensive part of a solar setup. I’ve found a way to bypass the need for a battery, and I think you’ll find it interesting. Let’s dive into how to set this up, and we’ll also test it to see how it performs.
The System Overview
This system is incredibly simple. We have two wires coming from the solar panel that connect to a 24-volt input and a 12-volt output converter. This setup allows us to measure how much power is being produced. Additionally, I’ve included an XT60 connector so that multiple 12-volt appliances can be wired up to it. Honestly, anyone can build this. You don’t need to use XT60 connectors; crimp connectors will work fine. However, without a battery, you must have the solar panel in full sunlight to produce power.
Testing the System
First, let’s connect a laptop to the system and see how many watts it uses. The laptop is charging with 20 watts of power, and the charge indicator is on. Let’s see if we can turn the laptop on. It’s powering up! It was completely dead a second ago, which is pretty incredible. The power usage fluctuates between 19 watts and 29 watts.
Next, we’ll connect an inverter to a 75-watt solar panel and see if it can power a fan. The inverter turned on, but it seems the fan is too big. Let’s try a smaller fan. It works! We are powering an induction load on a modified sine wave inverter without a battery. This is quite impressive.
Practical Applications
This system can be especially useful. For instance, if you have a small DC fan on your roof, you could power it with a small solar panel and a converter. This means the fan will run whenever it’s sunny and warm, and turn off when it’s cold and dark, creating a self-modulating system. The setup continues to produce great power, which is quite surprising.
How Converters Differ from Solar Charge Controllers
Solar charge controllers like PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking) are designed to work with a battery. They need a battery to function properly, as they rely on a reference voltage to charge the batteries safely. They have charge profiles, whereas a converter does not. A converter simply takes in 24 volts and outputs 12 volts, with slight variations depending on the design.
Something interesting to note about converters is that they often contain large capacitors. These capacitors act like small batteries, reducing noise in the system by providing instantaneous bursts of power, ensuring a steady output suitable for electronics. This makes converters ideal for direct solar panel connections.
Setting Up the Converter
Here’s a basic setup:
- Converter: Takes 24 volts in and outputs 12 volts.
- XT60 Connectors: Used for connecting multiple appliances.
- Watt Meter: Measures the power going through the system.
You need a solar panel with an open-circuit voltage around 20 volts, which drops to about 16 volts when connected to the converter. This output is enough to power various 12-volt appliances.
Safety and Efficiency
This converter is 90% efficient, compared to the 70% efficiency of some PWM controllers and the 95-98.5% efficiency of MPPT controllers. However, for a small, mobile system, this converter works well. It has safety features like over-current and short-circuit protection.
Conclusion
This simple and straightforward system, consisting of a 24-volt to 12-volt converter, works well for charging devices directly from a solar panel. A 100 to 200-watt solar panel would be ideal for this setup. You can connect multiple appliances using XT60 connectors and adapters available at hobby stores.
Before using this setup, always check the voltage coming out of the converter to ensure it is safe for your appliances. Most 12-volt appliances can handle up to 14.5 volts, so make sure the output voltage is within this range.
This system offers an affordable way to harness solar power without the need for an expensive battery. It’s fun to experiment with and can be a great addition to your off-grid setup. For more detailed recommendations on DC converters and solar panel sizes, check out my website. Enjoy experimenting with solar power!
