I know how many of you inventors have desired a versatile battery holder to power your projects, I know you can't sleep without that... so this strange accessory has born ;-)
This gadget has a simple function, keep a battery inside, and yes you could buy an ordinary plastic black and impersonal battery holder if you want, but keep in mind that this is coloured (you can choose the Sugru colour that you prefere), rubbery and even water resistant (although you can't dive with it...).
Step 1: The Actors
I made it for Li-ion 18650 batteries, because they're very powerful and really versatile for electronic projects, but you can build the same gadget for one or more batteries of any type, voltage and shape.
I've used some metal washers to make contacts, maybe copper pieces should have been better because copper is more conductive... I'll let you know after some test.
Step 2: The Roles
To choose the right washers you have to give a look to these two images. As you notice the fat washer can't make contact with the negative side of the battery, so we'll use it for the positive terminal. Same matter for the thin one, theoretically it shouldn't touch the positive tip so we'll keep it for negative flat side. Pay attention to avoid any shortcut when working with powerful rechargeable cells, it could be danger and damage your batteries.
Step 3: The Teams
Let's melt some tin on the washers. Probably you should find it very arduous because tin doesn't stick on the steel of the washers, in that case it's essential spread some flux on them.
Step 4: The Bands
Now you can choose some good quality natural rubber bands (better with flat sides, not as mine), the more they're tense on the batteries, the more they'll keep the contacts connected. You can try with only one band for each battery if it's enough strong.