DIY e-bike - Surly Ogre All-weather commuter
FYXO

DIY e-bike - Surly Ogre All-weather commuter

Curating custom bikes for people is something I've done, dare I say 'since forever'.   Close enough to 20 years and the most common way they come about is someone desiring something akin to my current ride.  First it was track bikes, singespeeds, classic road bikes, and the last few have been e-bike conversions capable of carrying either small humans, bulky gear or a combination of.

I've had an ebike for yonks and love how versatile they are as a mobility tool.  'Guiseppe di Greco', International Man of Mystery came a knockin' wanting something similar to the last Tonka build.  There were a few candidates tossed around for the chassis, and we locked in the latest Surly Ogre in 'Champagne Supernova'.   I managed to snag the very last one from Commuter Cycles and the scene was set. 
La Marzocco was the theme for graphic design as Giuseppe has deep roots in dealing caffeine, and also in the ol' by and sell game across fashion, furniture, bikes and art.   The brief was a bike for all-seasons commuting, towing his nephew around on weekends with a tag-along and potential bikepacking weekenders which is where the Mezcals (tubeless) come into their own.   
Deviations from the stock Surly offering starting from the cockpit are the Thomson stem, Loop bars, and ODI grips.    If you haven't enjoyed the relaxed vibe of the bar position, do yourself a favour.   The Avid cable brakes were subsituted for Shimano hydraulics for increased power and modulation. 
The Bafang motor display is the SW102 and at the time it was the most minimalist available.  It does everything you need, and with the battery concealed in the frame bag this doesn't immediately scream 'ebike'!
Not all frames will have 3 bidon bosses to mount the battery, or they'll be in the wrong spot for ideal mounting so an extra rivnut was added.   The battery sled then mounts directly to the frame through the bag, hiding the battery, cabling and leaving room for snacks, spares, gloves and tools.
The chainline with the 36t chainring was great, unlike the fat bike builds where an aftermarket Lekkie Bling-Ring is a must and adds a significant chunk to the build budget.  These motors like to spin rather than grind so the smaller chainring has many benefits.  Easier pedalling in the event of the battery hitting the dreaded 5%, less strain on the drivetrain (chain, cassette, pawls) and lower top speed.
As easy as the Bafang Mid-Drive kits are to install, the trick - if there is one - is getting a result that doesn't look like a 3 year old threw their spaghetti bolognese at a wall.  A google image search 'DIY bafang ebike' will colour that mental picture for you.   Inside the bag is the switch to turn on the front / rear lights, the main cabling is also concealed, and the enemy of electrical components (water) will have a much harder time interfering.
The only downside to the Bafang mid-drives is the lack of a torque sensor.  While they allow for easy transformation of almost any bike, the power assist levels on Bafang mid-drives are effectively cadence levels.   Integrated systems like Bosch, Shimano et al are a more intuitive riding experience.  
A few hours after I'd delivered the bike, Giuseppe was miles away, exploring the bayside suburbs, cruising into the city and testing the 'range' of his new rig.    After spending all day on your feet at work, cruising home by bike with as much assistance as you feel like is a treat.  Say g'day if you see him on the street! 
If you've got any ebike conversion related bike questions I'll do my best to answer them to the level of my current expertise.
For the velospotters:
Frame / Fork - Surly Ogre XL
Headset - Cane Creek
Wheels - WTB Novatec
Shifter - Microshift 10s
Derailleur - Microshift Advent
Crankset - Bafang
Chainring - 36t
Motor - Bafang BBS02 750w
Battery - 48V 17.5ah
Display - SW102
Cassette - OE 11-42t 10s
Chain - KMC X10
Post - 27.2
Brakes - Shimano Deore Hydraulic 
Tyres - Vittoria Mezcal 2.35 skinwalls
Handlebar - Loop
Stem - Thomson X4
Grips - ODI
Fenders - SKS Blumels 75mm
Cage - Ti 
Saddle - Brooks Cambium C17
Pedals - Rockbros platform
Extras - Custom 'LA FYXO' decals, Blackburn Outpost Elite Frame bag (large), 4mm shock cord, Stainless schteel double wall flask, Quad Lock out front mount, 4WD slimline light bar, rear light, Ibera racks (front & rear).