Handlebars can get pretty cluttered on an e-bike and some combinations of controls on a DIY e-bike just don't work well can get downright crowded and awkward. We often have to make less than ideal compromises in locating our handlebar controls and equipment.  Here is a set of bars where the best compromise required the shifter to be placed so far from the grip that it is an awkward and sometimes dangerous maneuver to shift.

Now I happen to like half twist throttles and rapid fire shifters. Unfortunately, most rapid fire shifters do not clear the large bulge on the half twist throttle.  ​ After giving up trying to make the rear derailleur shifter work where it belongs on the right side, I ended up turning it upside down and moving it to the less cluttered left side - definitely not ideal.

 
Some DIYers just move the throttle over to the left and keep the shifters where they belong on the right but having spent years on motorcycles, I just couldn't get use to that.  So the shifter ended up being upside down and backwards. It worked but not what I wanted. I wanted to find a way for all of my new e-bike controls to fit with the regular bicycle controls exactly where they are supposed to be.  That is when I discovered Shimano I-Spec. brakes and shifters.  I-Spec is simply a design that allows the shifter to share the same clamp as the brakes if they are both I-Spec compatible.  It turns out SRAM was the first to do it and Shimano's answer was to come up with I-Spec.  In improving it Shimano has released several versions, I-Spec A, B and II.  I am not going to go over the differences here as there is a good article covering that here.  While I was upgrading my drive train to a wide-range 1x10 cassette to give the best possible range of gears for a BBSHD, I took the opportunity to clean up my handlebars using Shimano I-Spec B components. ​  I upgraded my Avid BB7's to Shimano Deore M615 Hydraulic Brakes which are I-Spec B compatible.  I replaced my 9 speed Deore derailleur and shifters with Shimano XT 10 speed components.  More about the unbelievably superb (for BBSHD conversions) wide range cassette and drive drain upgrade here. The shifter is an I-Spec B Shimano XT M780 10 Speed Trigger Shifter. 

Not only does the I-Spec B shifter clear up space on your bars by sharing a clamp with the brake lever but the shifter levers are raised higher off the bars such that they clear the bulge in the e-bike twist throttle and are in the perfect location,  Sweet.  Additionally, the left side allows the Bafang Power/PAS control switch to be located in a better position right next to the grip.