Guest post by Dalibor
Description of the making of a battery housing. It was made of polyester. Very tough, waterproof and shaped to fit the bicycle frame.
For this model I made two housings, because the planned amount of battery cells required a lot of space. It was made using styrofoam, which was then used to make a frame and apply polyester.
Polyester is very easy to shape, but also very difficult to work with.
Styrofoam cut and shaped 
Frame for applying polyester 
Applying polyester onto the frame 
Polyester completely applied and dried 
Preparation for cutting out the housing lid 
Cut out battery housing lid 
Battery housing with a lid
White colour perfectly matches the bicycle’s colour.
Housing lid mount 
Painted housing parts 
Finished and assembled battery housing
Small housing was made for indicators and a small voltmeter.
Voltmeter and indicators housing 
Voltmeter and indicators housing – finished
Polyester housing is very resistant to weather and other outer influences. It can be shaped to match bicycle frame design and shape. Housing can also be made from other materials – like aluminium, chrome etc.
This is how the finished project looks: Specialized modified to be an electric bicycle. 🙂