SOLAR USB CHARGER

Dear all,

We have made a Solar USB charger for science exhibition in one of the Bsc college,

20*4 LCD

Dear all,

We have done 20*4 LCD being driven by Arduino for one of the Bsc College project for science fair.

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MPPT CHARGE CONTROLLER

Dear all,

Here we are with Arduino based MPPT charge controller.This project is inspired from Mr. Tim Nolan’s Arduino MPPT. We can share this as long as we mention his website link.

Here is the link:  Click here

The display part is taken from the KIBI: Click here
We didn’t use Tim Nolan’s hardware as we wanted to be different and simple (No MAX IC’s).

Our circuit diagram is given below:

We tried to make the circuit using IRF5210 because of high input capacitance we shifted to IRF9540. We used instrumentation amplifier TL082 to amplify the solar current. To generate –ve voltage required for TL082 we used 555timer and lm7905 for -5volts generation Modification in the software:

We modified the code so that PWM is around 20 KHz and our MOSFET’s are happy at this lower speed.

For your reference this is the link for Mr. Tim Nolan’s circuit:

Click here

DC DC CONVERTER FIELD TEST

We have tested the DC DC converter in field yesterday in SALEM. The two units are working more satisfactorily than we expected. We connected two solar panels of 100Watt in series to get the 40Volts on no-load and 36Volts on load (Battery). The test is continued till the shade falls on the panels at 5:30. For 2hrs the battery gets fully charged.

Improvements in the 2^nd unit:-

There was a high frequency humming sound in the transformer. To reduce that we increased the turns ratio from 7:5 to 8:6. We added two high voltage capacitors (1000uF & 0.1uF) at the input to remove spikes. We relocated the diode to improve the heat dissipation. The MOSFET and Diodes are placed in the front and back panel respectively. The raise in temperature of panels is less than the previous unit.

The pictures of 2^nd unit are given below.

The schematic diagram is shown below.

For more details please feel free to contact us.

BATTERY BOOSTER

This project was originally published in November 2004 QST. We have made the simplified version as shown in the below schematic.

Performance verified at 5A continuous load current to prove the design. For further details feel free to contact us.

DC to DC converter

It is a simple DC to DC converter. The input is from two solar panel with minimum Voltage of 24V, typical voltage of 32V and maximum Voltage 40V.The Output current is 10A @13V.This seem to be highly efficient. No heat sinks are used for the MOSFET and diodes. Only 3mm thick aluminium sheet is used for front panel on which power devices are mounted. We tested it for 2 hrs with output current of 4 A @ 13V, the temperature of front panes raises only by 2 degrees Celsius.  For other details please feel to contact us.