Sunny Buddy should be avoided. It uses a really bad device from Linear Technology. 
I’ve tried to make it work, but not possible. I and my team have given up trying to use it.
None of the solar panels offered by SF will work. They are all 6V.
The device requires over 3V headroom just to turn on. So if you try to use a LiPo battery at 4.2V charge voltage, you need more than 7V. And to make matters worse, if the voltage is too low on startup, it goes into a “limp” mode where the output voltage never rises to more than 1V. You can verify this verify this using LTSpice. Make the input voltage ramp up to 6V and you’ll see the problem.
P.S. GET RID OF THAT ANNOYING TEST FOR HUMANS. It asks me almost every time I navigate around the SP website. Makes me not want to come back.
