Solar panel voltage limiter

In case your solar panel has a little bit too much open voltage, you can introduce a voltage limiter. For example, my solar panel 6V 4W goes up to >7V in open load. This can damage the LiPo Rider or DFrobot solar power manager as those boards accepts upto 6V.

Here is an example:

Several solutions exists, just make sure the output voltage will follow Vsolar when lower than normal regulator value.
I build this one with components I had on the shelf.
The 2.7V Zener will add an offset to the 3.3V LDO, pushing it up to ~6V.