USB charging with solar panel

[Larsmartinxt]

This is my first contribution to this forum

I got tired of those cheap solar USB chargers that never works so I decides to make my own.

The panel I made is a bit of overkill for the rest of the circuit as the charging done is only 5w from my boost converter. But this makes it work in partly cloudy weather as well as in bright sunshine.

Panel consists of glass/eva/solarcells/eva. Didn't use tedlar as I couldn't find it

The Boost converter boosts voltage from 0.7V up to 5V so it could work with as few as 2 cells. Had the circuit board made professionally as I ordered 50

Anyway let me know what you think.

[DamonHD]

Nice work: is the boost circuit your own?

Rgds

Damon

[Larsmartinxt]

Yes I made the boost circuit. It's core are the MAX1674 chip

Charges my cellphone in a couple of hours

[ghurd]

That is 'backwards" from anything I ever saw.
Stepping down to USB from 12~24V nominal is more common.

Nice work!
G-

[Larsmartinxt]

That is 'backwards" from anything I ever saw.
Stepping down to USB from 12~24V nominal is more common.

Nice work!
G-

Yeah well I figured when I only need a few watts why use a bigger panel...  This is for charging cell phones,GPS and such when going tenting

[ghurd]

"I figured when I only need a few watts why use a bigger panel"

Watts is Watts is Watts, but I know what you mean.
G-

[DamonHD]

Can you link to or attach a schematic?  Is it a huge secret?  B^>

Rgds

Damon

[Larsmartinxt]

Can you link to or attach a schematic?  Is it a huge secret?  B^>

Rgds

Damon

I could post it but then I'd have to kill you..

[DamonHD]

Thanks: nice and simple!

Rgds

Damon

[richhagen]

Nice project.  I made an imperfect panel of about 3 volts or so a while back, laminating it in a vacuum oven.  It does about 2.5 Amps and apparently might make a nice cell phone charger.  OZtules has used Tedlar, commonly sold in building supply places as a backing on some panels, I believe with success.  He has a nice writeup about how he builds his panels on here too.  Rich

[Larsmartinxt]

Nice project.  I made an imperfect panel of about 3 volts or so a while back, laminating it in a vacuum oven.  It does about 2.5 Amps and apparently might make a nice cell phone charger.  OZtules has used Tedlar, commonly sold in building supply places as a backing on some panels, I believe with success.  He has a nice writeup about how he builds his panels on here too.  Rich

I actually used a professional machine for laminating solar panels. This was on the lab of a local solar cell manufacturer.
Was planning to use Tedlar. but someone had misplaced the roll so didn't use it this time. 
Yes you could use that panel no problem. 

I've been reading that writeup and it's excellent. Was planning to use that method. And will probably use it later.