Solar Powered Charger

[vinnie_c]

Hi. I am building a solar powered charger. I am using two MPT6-75 solar panels; output v=6v, i=50mA, connected in parallel, for higher current. I want the output voltage to be 5v. So at first I used a 5v voltage regulator. But the charger is not working. I found out that for the regulator to work I need at least 7.5v to work. So then I read about a step-up/down regulator, MAX710. And thinking about it, this seemed more like the thing I would need because the panels give varying voltages from 0 up to 8v. However, I do not know how to use the MAX710. I have been reading the PDF but am confused. Would this work to supply a steady flow of 5v and anywhere between 500 and 100mA? Also, can you explain how to use the MAX710; do I have to make a circuit board to mount this on?
Thanks for any help.

 

[Nigel Goodwin]

It's a charger - you don't need to voltage regulate it, and the tiny output of the panels probably isn't enough to overcharge batteries either.

 

[Optikon]

Hi. I am building a solar powered charger. I am using two MPT6-75 solar panels; output v=6v, i=50mA, connected in parallel, for higher current. I want the output voltage to be 5v. So at first I used a 5v voltage regulator. But the charger is not working. I found out that for the regulator to work I need at least 7.5v to work. So then I read about a step-up/down regulator, MAX710. And thinking about it, this seemed more like the thing I would need because the panels give varying voltages from 0 up to 8v. However, I do not know how to use the MAX710. I have been reading the PDF but am confused. Would this work to supply a steady flow of 5v and anywhere between 500 and 100mA? Also, can you explain how to use the MAX710; do I have to make a circuit board to mount this on?
Thanks for any help.

Lets see....
6V input at 50mA = 0.3W and 5V out at 100mA = 0.5W!

Well no, you wont be able to create energy from nothing.

How's about 5V output @ 48mA assuming 80% efficiency (not tough)

I know nothing of the MAX710 but first check your power calculations to see if it is physically possible.

 

[audioguru]

The solar panels will produce 6V/50mA only at noon on June 21st on a very sunny day if the panels are pointing accurately at the sun. The output will be less in any other condition. It might take weeks to charge a battery.