12v Solar Power without a battery
If you have a small 12v appliance that you wish to power/charge when the sun is out, you can use a 24v\36v to 12v step down converter. This will modulate the power produced by your solar panel into a voltage that is suitable for your appliance.
This system does not work well for powering:
You have 3 variables to consider when sizing these battery-less systems:
Example: If I need to power a 50 watt fan, I would use a 100 watt solar panel, and a 20 amp converter.
You will need to size the converter to your solar panel. The solar panel also needs to have a open circuit voltage that is less than the max input voltage of the converter. Because these converters can typically only handle 40 volts max, you will need to wire your solar panels in parallel.
Equation to figure converter amp rating: Solar Panel Wattage / Open Circuit voltage of Panel = Amp output of solar panel = Max input in amps that the converter can handle.
The most important thing that you need to do when building these systems is to check the output voltage! Some converters output voltage will rise with input voltage. If your solar panels produce a high voltage that your converter cannot handle, problems will occur. If you use the converters I recommend below with 12v solar panels wire in parallel (which will only produce 20-22 volts open circuit max), you will be good to go.
This system does not work well for powering:
- Large loads
- Induction loads
- Inverters
- DC fans
- Laptops
- LED lights
- USB devices
You have 3 variables to consider when sizing these battery-less systems:
- Solar Panel Array Size
- Converter Size
- Appliance Size
Example: If I need to power a 50 watt fan, I would use a 100 watt solar panel, and a 20 amp converter.
You will need to size the converter to your solar panel. The solar panel also needs to have a open circuit voltage that is less than the max input voltage of the converter. Because these converters can typically only handle 40 volts max, you will need to wire your solar panels in parallel.
Equation to figure converter amp rating: Solar Panel Wattage / Open Circuit voltage of Panel = Amp output of solar panel = Max input in amps that the converter can handle.
The most important thing that you need to do when building these systems is to check the output voltage! Some converters output voltage will rise with input voltage. If your solar panels produce a high voltage that your converter cannot handle, problems will occur. If you use the converters I recommend below with 12v solar panels wire in parallel (which will only produce 20-22 volts open circuit max), you will be good to go.
My Tested Converter Setup
300-1000 watts of solar panels
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30 amp 48v to 12v step down converter
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Because most 100 watt solar panels will only produce 70 watts each, a 300 watt array will produce around 210 watts or more in full sunshine. This converter is rated for 360 watts, and 30 amps output, so this would work well to power 200 watts of 12 volt appliances continuously. If you hook up your appliances and your appliance fails to work, you probably do not have enough power, or the startup surge required cannot be fulfilled with the solar panels. I have tested these converters with induction loads on inverters, and I ran them all day! So most 12v dc appliances should work well.
So connect the solar panel array to the input of this converter, then connect the output to your small inverter/cigarette lighter laptop charger etc. You will need to buy a cheap wire stripper and crimper tool set from amazon or a local hardware store. This setup can be built in minutes.
So connect the solar panel array to the input of this converter, then connect the output to your small inverter/cigarette lighter laptop charger etc. You will need to buy a cheap wire stripper and crimper tool set from amazon or a local hardware store. This setup can be built in minutes.
A Super tiny system for powering USB/Laptops etc
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This system can handle enough to power most laptops and/or USB devices