The Chimpy charges my phone only partially, not 100%. What is the reason for this?

Our Chimpies should be able to charge a smartphone to a 100% at least one time. If not so, this could be the reason:

• If you charged your smartphone already and now you plug it in a second time. It could be that the Chimpy will not be able to recharge your phone entirely.
• If you are intensively using your smartphone during the charging period, it can occur that the Chimpy will not be able to fully charge your phone.