Lm2596 fixed 5 volts(usb) from 12v 10W solar panel

chargersolar cellusb

I have got a 10 Watt solar panel & a 10000 mha Battery bank. I plan to use the panel to charge the battery bank.

I have a LM2596(variable configuration with pot), I plan to use it to charge my battery bank /Other device directly from the 10W Solar panel.

I have 2 Questions:

Q1 . If I remove the Pot and short the feedback with load (as suggested in the Datasheet), will it give me fixed 5v Output irrespective of the varying voltages of the Solar Panel throughout the day?

Q2 . The Datasheet suggests for fixed output of 5V the Max input voltage is 12V . the Max output of the Solar panel is 17 V so without fiddling with the circuit much, can this be done ?

Best Answer

If you have the 'fixed 5v' version (LM2596-5.0) then you can connect the feedback pin to the output. But since it seems you actually have the 'adjustable' version (LM2596-ADJ) then you'll have to use the correct voltage divider between the output and feedback pins. See the instructions starting towards the bottom have of page 12 of the datasheet. You'll get 5v out as long as your solar panel gives you at least 7v in.

The 12v input for 5v output shown in the datasheet is just an example. This IC will quite happily run off 40v and give you a 5v output - check the 'LM2956-5.0 Electrical Characteristics' table on page 3, or the LM2956-ADJ table on page 4.