Holder for 18650 Li ion battery. I built a 4x6 tray to make a 24volt Li ion battery to replace the Lead Acid batteries in my son's Razor scooter. Basically, I copied the stackable holder that you can buy online. Hole size is 19mm to accommodate the 18.5mm battery diameter. I tried several sizes and this works best. Print with the tabs up and Makerbot supports are small and easily removed. Use Autodesk 123 D to make a tray of any size by copy and pasting the single holder. The tabs protect the wiring and prevent battery from pushing through. 6s4p battery pack wired up with battery protection board. Bought protection board on Ebay. In "Tim Allen" fashion, I had to overvolt the Razor with a couple of extra banks of batteries to bring volts to 36volts. Works great. Even I can ride these scooters and I am way over 130lb limit. Update: Razor E200 modified to 250Watt MY1016 brushed motor with 1000w Yiyun controller. 10s4p battery pack running 42volts when fully charged. The scooter is pretty fast for an 11year old to ride.