RFC Solar Cgarge Controller

RFC Solar Charge Controller

Hi group.

I put together what I like is a simple Solar Charge Controller. I would like you to examine it and tell me if you think it will work?

The therory of operation is:

• Power comes from the solar panels
• The TIP2955 pass power when they are grounded
• The LM317 creates a reference voltage of 13,7 volts
• If the battery voltage is over 13.7 volts the LM741 shorts the TIP2955 ground

I am concerned about R1, is it placed correctly and is it the right value?
What do you think?
This is another one of my "Monkey See. Monkey do" projects.

What is the max base current will ever get to the power transistors?(Hint: Ohms law)
How do you guarantee that current is shared equally by the power transistors?
Why regulate the supply pin on the 741? (Hint: look up PSRR).

How much current is your panel capable of?

I can show you how to do this with about 5 components, but first you have to answer my questions.

What is the max base current will ever get to the power transistors?(Hint: Ohms law)
How do you guarantee that current is shared equally by the power transistors?

Click to expand...

I forgot the resistors. A 0.1 ohm 5W resistor in each input leg of the TIP2955. So is that the answer you are looking for? Remember, I'm a software guy not a double E.
MSMD( Monkey see, monkey do ).

Why regulate the supply pin on the 741? (Hint: look up PSRR).

Click to expand...

I though that a lower voltage would be better to keep the heat down?

How much current is your panel capable of?

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Dead short, 3 set of 3 panels produce appox 18 volts at 18 amps. Monitoring the charge current the most I see is 11 amps. Have not monitored the input voltage.

I can show you how to do this with about 5 components, but first you have to answer my questions.

Click to expand...

I'm listening!

My web resources:

• **broken link removed**
• 12v30a.png (image)
• http://www.datasheetcatalog.org/datasheet/stmicroelectronics/4136.pdf (PDF)

Here is a variation of regulator I came up with for a linear power supply/battery charger. When I said five parts, I thought you could use a shunt regulator, but at 12A and 14V (168W) that is not practical. I know this series regulator works because I have already built it.

For your solar panel, I crudely modeled it as a current source of 12A, shunted by a voltage to clamp it's open circuit voltage at near 18V. I modeled your battery bank as though it is a 12V flooded-cell lead-acid battery which is charged at 14.25V. I included a realistic series resistance. For simulation purposes, the 50 Farad capacitor charges about a factor of 100 times faster than your actual battery will charge. So in the real world, seconds become hours

Note the power dissipation in the PFET. It has to be mounted on a very large heat sink. Or you may mount it on a surplus CPU heatsink with integral 12Vdc fan.

Thanks Mike

Mike,

Thanks for the design. I need to study it and see if it is within my capabilities. Remember, software weenie.

Hello world,

can you help me find a solar controller with ATmega16? Thanks a lot

Elecholic said:

Hello world,

can you help me find a solar controller with ATmega16? Thanks a lot

Click to expand...

I would recommend that you start a new thread.

MrUmunhum said:

I would recommend that you start a new thread.

Click to expand...

https://www.electro-tech-online.com/threads/help-mppt-solar-controller-schematic.92224/

that's the link buddy.

thanks

damit! now I am stuck in a loop!

I think what he ment was to start a new thread in the main area not in an older thread.