USB / DC / SOLAR LITHIUM ION/POLYMER CHARGER with ultracap

General project help for Adafruit customers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
User avatar
zener
 
Posts: 4567
Joined: Sat Feb 21, 2009 2:38 am

Re: USB / DC / SOLAR LITHIUM ION/POLYMER CHARGER with ultrac

Post by zener »

I would remove both diodes. Just connect the cap directly to the second booster. I don't really see the purpose of the bypass diode either. I don't have experience with solar cells but that LT part LTC3128 looks pretty nice. They do make a dev board for that but I didn't see anyone selling it. Maybe you can get a sample from them. If you lay out your own board you have to connect that ground pad underneath so you will need hot air or IR.

The second booster is probably necessary if you want to run a 5V system but you would probably be better off if you could run your processor off of 3.3V instead of 5V. The capacitor voltage will drop precipitously as the boost level increases, a "snowball" effect. You also have to weigh the losses from the quiescent current of the booster vs. the extra life you potentially get. You could test with and without the booster and see which lasts longer. Like I said before, the biggest "bang for the buck" is reducing the load as much as you can. This will have the greatest effect on the backup life.

User avatar
pedrorojas
 
Posts: 8
Joined: Thu Aug 14, 2014 5:22 pm

Re: USB / DC / SOLAR LITHIUM ION/POLYMER CHARGER with ultrac

Post by pedrorojas »

Ok and I'm gonna use an Arduino, there is a way to lower the input voltage but I have to hack the board, I'll think about reduce the load all I can. Very thank you Zener.
Please keep the notify when I posted something on, just in case

Locked
Please be positive and constructive with your questions and comments.

Return to “General Project help”