Greetings , I have the following scheme a solar panel of 6V 3.5W ([solarpanel) with a two parallel acumulators Li-Po 3.7V 3000mAh(in total 6Ah) . I’ve been following [ the hook up guide on SB and I get confused , I could just set it to 3V(2.7V “kneel” voltage or Peak Voltage), but from this manafucter I get the PV which is 6.5V . So why questions is if I set the potionmeter at 6.5V will it charge or I got this whole thing wrong ?](Sunny Buddy Solar Charger V13 Hookup Guide - SparkFun Learn)](Zonnepaneel - 6V 3.5W | Kiwi Electronics)
Thanks for reaching out to us on this.
The ideal setting would be achieved via:
Plug your solar panel into the Sunny Buddy, but don’t put a battery or load on it.
Measure the voltage from the “SET” pad to the “GND” pad next two it, and tweak the potentiometer until that voltage is about 3V.
At that point, the Sunny Buddy will draw current until either 450mA is going to the load and the battery or the solar cell voltage is 90% of its full-sun open-circuit nominal voltage…
…which will match the PV of the solar panel’s output, taking over when/where appropriate.
Setting the SunnyBuddy to 3v, to match the solar panels’s “knee” PV of 6.5v
→ this is how the SB assists when the panel’s voltage drops below a usable level (current-flow too low)
Hope this helps, and happy sparking!
Thanks for the help 
!
Set-up is easy as well, just plug your solar panel into one side of the Sunny Buddy and your battery By default, the Sunny Buddy comes set to a maximum charge current of 450mA with a maximum recommended input of 20V (minimum 6V).
This might be a silly question, but what happens if I have a solar panel that sometimes gets to 21 V? would it fry my Sunny buddy? is there anything I can do to avoid that? 
Anything over 20v runs the risk of damaging the board…it might, if left for a while in a hot/warm area, it might not hurt it all in a cold environment (as the cool would help whisk away the heat from the power)
You could either put something to limit the voltage between the SunnyBuddy and panel leads (DC to DC converter, Buck converter, or similar…just make sure it matches the voltage range needed), or you might be able to “shade” a small portion of the panel to reduce its peak outputted voltage output to <20v (basically, block a bit of sun from reaching the panel)