I do a lot of work with drones and so I have accumulated quite a collection of LiPo batteries. It's always been a challenge to remember which ones have been used and which ones are fully charged. I'm constantly looking for my battery meter to check each battery before use. Recently I saw these charge indicators on Hobby King. Such a simple and elegant solution, just colored silicone covers that slip over the end of the XT60 plugs. Looked like something I could print.
I took some measurements and drew up the covers in 123D. I recessed the text so I could add paint. I printed them in PLA at 0.1 mm layer height. I found that the dimensions of the XT60's differ slightly depending on the source. These are a friction fit so you may need to scale the prints slightly to fit your particular battery. The files are available on Thingiverse and YouMagine.
