A Couple of Giant MTB's, now with 200% more EM3EV!

These bikes have been with us for almost a decade now. In that time, this is the second attempt to electrify them - this time around I would say it was a solid success! There were two previous factors of failure - the battery size/reliability, and the overall weight.

We did our first outing on the bikes yesterday - it had been over two years without riding for the both of us, amazing how time flies! The bikes are two aluminum Giant Yukon hard tails. Our primary mode of operation is most commonly rail trail, to this point. We like to bike for fun and fitness, and recently we could use far more of the latter...





The kits from Paul @ EM3EV were leaps and bounds ahead of what we had to work with last time around, I think they will prove to be reliable enough to keep us in the electric camp for some time. Two 'upgraded' MAC 8T geared hub motors, 12 FET Infineon 40A controllers, and a 14S (50V) 15ah LiMn battery, along with a couple CA v3's. I was happy to be able to program some selectable presets with these kits using the 3-pos. switch on the throttle assembly. I have set up a 350W/15mph 'Economy', a 750W/20mph 'Legal' and an 'OffRoad', unlimited profile. Having the temperature sensor data available at a glance was really very useful when climbing or pushing the limits, I think that is a great addition for longevity.

Yesterday we rode for testing, and also exercise. We turned in about 4 miles on the local streets and hills testing all the modes before hitting a section of rail trail - we rounded out the day at 10.8 miles and just under an hour of saddle time. We stuck to 'Economy' once on the trail and used the motors sparingly - an absolute wonder to be able to pedal without the motors cogging! The trip totals for myself was 11.1 Wh/mi and the wife came in at a miserly 7.7 Wh/mi, over that 10.8 mile distance. Being heavier (220 lbs.) has its disadvantages! I used just over 2ah out of the pack on our little journey, more than half was used during our first 4 miles "mode testing" the various capabilities. My backside will need a little R&R before the next round of testing, but so far I have been thrilled with the performance. I was able to hit 30mph on the level with no issue and could have gone faster I think, given more room to play... It even propelled my wife up a decent hill for her top speed of the day, at 27mph. You should have seen the grin on her face with these things - very happy customers here!

The kits added about 28 lbs. to each bike, which are now tipping the scales at just over ~ 60 lbs. a piece, which I think is quite manageable. The battery location is of course not ideal, but very handy to dismount and carry away with those quick disconnect Topeak bags. The Yukon alloy frames are fairly beefy in general, and I am using some old "Ampedbikes" torque arms to protect the dropouts. Hopefully with the 2KW and the added weight they will manage to hold up well over time, as our riding is generally not terribly demanding

Congrats, I bet they're perfect for a lighter trail/road ride @ 8-25mph with some torque.
Very good kit's by a great company, and best use of ca3 also. (Throttle, 3spd power/speed, and temp control.)

The only thing I may have done is used cheaper lighter hk lipo for 10-15 mi range on that build, helping the overall weight. I feel sure >200$ 8ah lipo would surely give you the power and range while saving weight &space.

Are you running speed, power, or current based ca3 throttle control? Did you use the official or unofficial guide to set them up?

Nice liteweight and energy efficient builds, have fun riding!

Thanks nutspecial!

I did the 15ah as a compromise vs. the first kits I put together years ago, which were 20ah LiFePo4 Prismatic, which was WAY too heavy for everyday stuff. These packs are about 8-10 lbs. and are quite manageable. I think I might do a lightweight LiPo pack for us later on as a short trip/lightweight option, and to have a 2nd battery on longer outings. I'd like to do the northern leg of the local Greenway trail, which runs from Champion, OH all the way to Ashtabula, OH on Lake Erie. That's about a ~ 40 mile one way leg. Our normal rec rides are usually in the 15-30 mile range once we get in better shape.... at least they were when we were human-powered only a few years back!

We've got a single wheel trailer I just got that I'm going to hook up, I need to turn some custom adapters since the axle posts won't work with the hub motors on there. That will give us more gear storage for trips and get some weight off the rear axle. On my bike, I think I'll move my pack to a case just ahead of the seat post upright - less stealth, but better balance. No room on the missus' bike frame for that, though.

The CA's were set up from Paul initially, I left a lot of it alone. I used the unofficial guide as a reference. The throttle's were set up for Thru mode (still are so far), but I prefer to have a torque based throttle like a motorcycle, or any normal "throttle" for that matter, so I'll probably give the Power mode a try. That should try to keep motor output consistent as the battery volts sag.

I checked out your build thread, that's a lot of getup in a light package! My original build parts that I never assembled on mine was a Clyte 5303 (or 5304??) and a Kelly 72V controller. Never got around to that due to the battery issues, but still have the parts. Maybe a full suspension frame for that one later on with the better batteries that are out now. First I have an El Moto project I need to start/finish, a KLR-650 that I've got a HPEVS AC-20 motor kit waiting in the wings for. It's always batteries that are the holdup for me, I always want something better that's just around the corner!!!

I didn't realize the ca could do active power& speed limiting on pass-thru mode. (easy way out on mine- clipped the green wire for pass-by). Yes the current/power modes do look promising. Really handy to have it all setup by Paul- Now I'm thinking about it for the next controller purchase from em3.
Thanks for the info, enjoy the projects, completed and otherwise!

Apparently the limits work in Thru mode, although I'd have to double check that I didn't change them. If the weather clears up today, I plan to do some more testing and configuring of the CA.

I wanted to stealth the wiring and controllers a bit more, so I went ahead and took care of that over the past few days. I moved mine to match the location on the lady's bike, underneath the pannier.



Also painted the controllers black with a thin coat, so they didn't stand out as much from oblique angles - the natural aluminum case is an attention grabber. I figured I'll leave my battery in the rear bag for now as it is much less conspicuous there, I strapped them down internally with some Velcro so they don't bounce and shift, which made a huge difference while riding.



You can see the motor lead is left in a service loop with Velcro ties, which is more than adequate to allow for wheel removal and servicing trailside.

Further mods I'd like to do - get a road bike 52T crankset, Truvativ makes one that fits this PowerSpline bottom bracket, which also needs serviced/replaced as I've noticed some play in the bearings. I need to get the tools and I'll check if this is a cartridge type or serviceable BB and go from there. I need some better kickstands for the added weight. I put a small DC-DC on the lady's bike for the headlight, I plan to get a larger one for mine to run auxiliary 12V items - pumps, lights, radios, etc. A Golf cart dc-dc should be perfect at around 20-30A.

I've done a couple more trips, one myself in town at full power, and we just finished a 20 mile section of rail trail with both rigs today. I was hitting thermal rollback at 100 C halfway through town with full blast accel from stops every block with some decent hills mixed in on this side of town. Traffic contention in 25mph zones was not problematic, as I was catching up to cars easily in block-to-block stop and go. It was just a short trip, 4 3/4 miles with a Wh/mi of 41.5. The 100 C is not a throttle cutoff point but the beginning of rollback - I think it's a nice safe setting and didn't seem to interfere with the return trip. Paul (em3ev) set the hard limit at 130 C which should give the halls some head room. My wife would probably not have the same thermal limit 'issue', being about 100 lbs. lighter. The motor temperature never exceeded 104 C during the trip.

Our 20 mile rail trail was at an average speed of 14.5 mph. I ran "Economy" mode 350W/15mph rollback on the CA, except for one section that runs with a roadway for about 1/2 mile - that was done full power mode, and at top speed. I can keep applying pedal power up to the top speed of about 33mph with this crankset, but I look like a lunatic doing so. I averaged 10.3 Wh/mi and the wife did 7.8 Wh/mi. I hope to see that number drop as we get in better shape, as our average speed should not be increasing on rail trail.

edit: On the rail trail, my motor temps were hovering right around 60 C, not sure on the wife's but I imagine at least 10C cooler.

I got the 52 tooth crankset installed on one bike as a test case, as I wasn't sure how it would bolt up, or if it would clear the chain stay. Good news:



I replaced the BB assembly at the same time, as I was beginning to feel some play in the bearings. I wasn't sure what size the BB was, and getting an exact measurement without a crank puller was basically fruitless. I ordered the special tools needed at the same time as the BB and crankset. Turns out I went from a 113x68 to a 118x68, which happens to have been quite lucky, as the left crank clears the stay by about that same +2.5mm. The 113mm spindle might have cleared at a hair's width, and I think the 52T gear would have been just clear as well, but I didn't try it on the shorter spindle to verify. My chain is too short now, and the first two cogs on the rear are unavailable until I fix that issue. Keeping me off the 11T rear cog as much as possible, as well as making high-speed travel cadence more tolerable, are the main benefits I see for this mod. I am not using a front derailleur, but went with the triple set for a better chainline, and I can still manually switch to a smaller front for long climbs. The 8 speed rear seems like it will give plenty for my normal use cases, as I had no problem with only having 3-8 available today on the ride.

Nothing else exciting to report, except a new trip total. We went ultra conservative on power use today on our standard route, optimizing Wh/mi as well as making it a fitness ride. I ended up with less use than the wife for the first time, by a few tenths of a Wh! We did the 20 mile rail trail circuit and turned in 4.6 Wh/mi! Average speed was down to 12.6 mph (from 14.5 mph). It's been awhile since our previous human powered rides, but the extra weight, drag of the geared motor, as well as the larger tires, seemed to have minimal impact to our speed capability under human-only power. I went with a 60/50 PSI front/rear tire pressure which seemed to keep rolling resistance in check.

The next project I have to work on is a "touring trailer" for longer rides, all the parts are finally here and I am starting on it this week.