We are able to build any battery, any voltage using the best and highest quality 18650 & 21700 cells. Although any size can be made, we do not carry any battery cases so custom batteries come PVC wrapped ready for your DIY mounting solutions. We use the highest capacity or highest discharge cells depending on what your requirements are for any e-device. We usually use Bluetooth BMS for the ability to monitor and set cut off values which is a game changer for any enthusiast. If you would like a quote or to discuss your project please email us anytime!