Solar Panel Voltage Boost Troubleshooting

In summary, the 50 watt solar panel does not have enough power to charge a 12 volt battery. To get around this, the user is using a DC-DC boost converter which is set to give an output voltage of 13.5 volts. However, the output voltage drops out after 10 seconds if the output voltage is set beyond 12.5 volts.
  • #1
davidsuzuki256
2
0
Hello,

I Have built a 50w solar panel that gives an output of ~ 9.2v @ 5-6 amps during a good day. This is not enough to charge a 12v battery. To get around this, I am trying to use a DC-DC boost converter (specifications are below) and it is set to give an output voltage of 13.5v. The only problem I have is that the output voltage drops out after 10 seconds if the output voltage is set beyond 12.5v. Input voltage becomes the same as output voltage thereafter.

Here are the specifications of the Dc-Dc boost converter:

Specification:
Size:(LxWxH) 70 x 39 x 32 mm
Wide Input Voltage Range: DC 6 ~ 35V
Output Voltage: DC 1 ~ 35V
Conversion Efficiency: 90%
Maximum Output Current : 5A
Maximum Input Current : 7A
Operating Frequency : 120KHz

What am I doing wrong?

David
 
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  • #2
davidsuzuki256 said:
Hello,

I Have built a 50w solar panel that gives an output of ~ 9.2v @ 5-6 amps during a good day. This is not enough to charge a 12v battery. To get around this, I am trying to use a DC-DC boost converter (specifications are below) and it is set to give an output voltage of 13.5v. The only problem I have is that the output voltage drops out after 10 seconds if the output voltage is set beyond 12.5v. Input voltage becomes the same as output voltage thereafter.

Here are the specifications of the Dc-Dc boost converter:

Specification:
Size:(LxWxH) 70 x 39 x 32 mm
Wide Input Voltage Range: DC 6 ~ 35V
Output Voltage: DC 1 ~ 35V
Conversion Efficiency: 90%
Maximum Output Current : 5A
Maximum Input Current : 7A
Operating Frequency : 120KHz

What am I doing wrong?

David
Welcome to the PF.

That's a pretty small input-output voltage differential for a simple boost DC-DC converter. You might need to use a SEPIC topology converter instead. Which boost converter chip are you using and with what component values?
 
  • #3
Or, wait. You are using a canned commercial DC-DC converter module? Can you link to the datasheet?
 
  • #4
Thanks for the response.

I am using this dc-dc boost converter: link.

I do not really care much about the output amp value. Only the output voltage has to be at least 13.5 for the boost converter to charge the battery. Unfortunately it doesn't last long and it will return to the open circuit voltage of the solar panel after 10-15 seconds. The booster also makes some ticking noises before the voltage drops to solar panel voltage.
 
  • #5
Your description of shutting down is almost always due to overload, current or thermal overload in this case. That particular model seems to be discontinued. Check this site to see if another model will fill your needs. Link. And pay attention to the warning about its usage!
 
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  • #6
davidsuzuki256 said:
Hello,

Battery may be drawing more than the rated current. Check with an ammeter. Also what type of battery - I assume lead acid.
 
  • #7
What is the voltage of the 12V battery before connecting it to the solar panel?
 
  • #8
As TomG and anorlunda have hinted it might be a problem of application.

What controls output current to the battery ? How much do you measure going to the battery ? Did you notice this caution in the directions at link you posted ?


buckbooster.jpg
 
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  • #9
davidsuzuki256 said:
I Have built a 50w solar panel that gives an output of ~ 9.2v @ 5-6 amps during a good day...
...
What am I doing wrong?
Without some numbers we can only guess what is wrong.
Hook it up again and take some measurements.

1. What is voltage from solar panel just before the stepup converter shuts down?
2. What is current into the battery at that time ?

Can you try this experiment - rewire your panels in series not parallel so they make 18 volts instead of 9 ?
Then connect them straight to battery without the converter and see how much current flows when sun is bright. Don't leave them connected very long lest you overcharge the battery.
That gives us a data point on solar panel's current capability.

Then insert your converter between the solar panel and battery and let it step 18 volts down to 13.5
In bright sun it should operate as step down and in weak sun it should act as step up,
and if i have read that datasheet correctly it'll auto-select whichever it needs.
With a little bit of luck the inherent current limiting nature of your solar panel will cure the trouble.
If not you might have to employ a current limiter.

old jim
 

1. How do solar panels generate electricity?

Solar panels use photovoltaic cells to convert sunlight into electricity. These cells are made up of layers of silicon that create an electric field when exposed to sunlight. When photons from the sunlight hit the cells, they knock electrons loose from the silicon atoms, creating an electric current.

2. What causes an increase in solar panel voltage?

The amount of voltage generated by a solar panel is directly proportional to the amount of sunlight it receives. Therefore, an increase in sunlight intensity will result in an increase in solar panel voltage. Additionally, the temperature of the solar panel can also affect its voltage. Higher temperatures can cause a decrease in voltage, while lower temperatures can result in an increase in voltage.

3. How can I increase the voltage output of my solar panels?

There are a few ways to increase the voltage output of your solar panels. One way is to connect multiple panels in series, which increases the total voltage output. Another option is to use a solar panel optimizer, which can help regulate the voltage and improve overall efficiency. Additionally, keeping your panels clean and free of debris can also help increase their voltage output.

4. Is a higher voltage output always better for solar panels?

Not necessarily. While a higher voltage output can mean more electricity is being generated, it is important to also consider the voltage requirements of your specific system. Too high of a voltage may cause damage to your system, while too low of a voltage may result in a decrease in performance. It is important to consult with a professional to determine the optimal voltage for your solar panel system.

5. Can a solar panel's voltage be too high?

Yes, a solar panel's voltage can be too high. This can occur if the panel is exposed to extreme sunlight or if it is connected to a system with a lower voltage tolerance. It is important to properly regulate the voltage of your solar panels to prevent any damage or issues with your system. Again, it is best to consult with a professional for guidance on proper voltage regulation.

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