pierce

My wife has a Specialized Globe Carmel step-through, 26" tires, v-brakes, SR fork, 3x7 speed... I'd fitted a Moxey suspension seat post to it and a nice soft seat... she hardly never rides, and when she does, she goes /so/ slow I find it painful to stay with her, I could darn near walk as fast.


so in the hopes we could spend more 2-wheel time together, I decided to try electrifying her bike.


bought a 1KW rear wheel with controller, and a 48V 18AH battery pack (865 WHr) that came with a rack it slots into.... hooked it up with the 'motorcycle' style throttle because the crank sensor seemed really primitive.







taken it for a half dozen test rides.... We live up a 300' hill thats 6-8% grade, so any ride involves a steep climb home for about 5/8 mile.... note we're both out of shape, 60-something.


discovered it works great, goes like stink until things sstart to get hot, then throttles down to like 300W but still power assists. I've done 15 miles of brisk riding and it still got up the hill and still had 2 bars. I've been leaving the front shifter in high, and just using the rear shifter, using 4 or 5 for accelerating and hills, 7 once i'm at speed. it can easily maintail the fastest I can pedal comfortably on flat ground with very light pedal effort and only using 200-300W.


discovered the power controller and the motor get hot after a 10-15 mile long brisk ride... in fact, first such ride, the bullet connectors on the hub-motor horness melted their insulators, which I replaced with silicon fusion tape. even now, the wiring gets rather hot, as does the controller brick, and the motor hub itself is pretty warm too. once it gets hot, it seems to limit the power output to around 300 watts, but actually that's plenty to get around, even up my hill when it was overheated, I maintained 10-15 MPH in gear H-5 not pedaling very hard witht he motor output at around 250-300W at full throttle...





I do believe i'm gonna leave the 750W limiter enabled in the future, I just uncorked it for todays short test ride down to the brewery to fill my growler

pierce

So... I'm already plotting my next ebike build... Thinking of using a mid-drive TSDZ2 on my 700c hybrid town-bike, and a smaller/lighter battery pack, maybe 36V 10AH (360watt*hour). The TSDZ2 is torque sensing pedal assist, so no throttle at all, just a gain control.

said hybrid as it was shortly after I built it up a few years ago...



thinking if I electrify this, I'll ditch the front derailleur, and just run a 48 or 52T ring, and use all 8 rear gears with a wide range freewheel. right now it has 48T-38T-28T which is perfect for my out-of-shape, the 48:13 is about as fast as I can sustain on level without a headwind, and the 28:26 lowest gear can crawl me up most any hill. but with 300 or so watts of assist, I expect that will be plenty. I do wish they had a 52-42 for this middrive, its got a funny crank offset, so its not easy to use generic sprockets and maintain a decent chainline.

Doc_Wui

Pretty nice. Does your wife like riding it?

pierce

so far, I haven't gotten her out of the driveway. she thought it was pretty cool going around the driveway... she vetoed my removing the motorcycle throttle and using the pedal sensor, hah hah.

I need to fix MY bike up (install new chain, and general lube-n-tune) so I can tag along (human powered), then go for a ride with her.

oh, I left out the best part of the build...

1000W 48V wheel motor kit with controls, display, motor controller, and rear wheel, $200
48V 18AH 865 watt*hour battery pack rack... $365
2009 Globe Carmel 1 woman's (bought as NOS in 2012)... $150

I'm *WAY* under $1000 even figuring the extra stuff I've bought for it, like the used Moxey suspension seat post (NLA since Cane Creek beat them to a patent with the same concept).

that reminds me, I should replace the rubber elastomer block on the Moxey, its hardened and doesn't have the right give anymore. the original Moxey block was way too soft for my wife and I (ok, we're both plus sized), so I found a rubber car spring spacer block was perfect, trim the ears off it, and wedge it into the Moxey, voila!

pierce

so the first thing I learned, a 1000W hub motor, and a 860 WH battery pack are *HEAVY*.

that combined with the somewhat unwieldy 'dutch bike' geometry of this Specialized Globe Carmel step-through, the original kick stand was very unstable.

After taking the pic above of the bike last week, I installed one of these 2-legged stands, but I'm not that happy with it. The right side leg pivots over and folds up with the left side normally folds. thats cool, and it mostly works, but when deployed, sometimes the right side leg is not real solid unless you're careful to ensure its fully extended.. Also, even with both feet at their shortest setting, its a bit too high for this 26" bike, the front wheel goes way off the ground. Maybe I should try removing the plastic feet, but then it would have a narrower base.

I should take some pics of this stand on the bike in various positions to explain this better.



CyclingDeal Heavy Duty Double Kickstand

Doc_Wui

When I built my fatbike, I didn't reuse the axle mounted side stand because I had added too much there, with a rear hub motor, torque arm and a disk brake adapter. My side stands on that 55 pound bike are problematic and eventually break.

Should have gotten an all metal pletscher center stand.
https://www.bikewagon.com/accessorie...320mm-silver-1

My wife would not ride your bike as 1000W kits don't generally use controllers that support slow speed riding. Low speed maneuvers can be tricky if the first assist level wants to go faster than you want. Let us know how it works.

I started by converting my son's old MTB. Cost $500 for motor/battery. Found it a lot of fun. I next did a fast mid drive, but have decided we (wife and i) like light weight bikes that are easy to pedal.

pierce

i discovered that allen screw on the 'back' was kinda loose, tightened it up, and it seems better.

I tried removing the plastic feet, didn't really help much, only lowered the front wheel about an inch, its still high in the air.

re: the 1000W kit, set to the 'street legal' 750W, the throttle gives pretty fine speed control, I'm not using the crank sensor at all... and rear wheel drive is a lot less skittish than front wheel drive.

anyways, here's some pics of this stand on the bike..









its all metal except the plastic feet covers, which can be used to raise the bike even higher.

pressed001

I can see your problem getting the right chainrings and chainline. Can't think of any solution right off the bat.

Hope your wife enjoys the bike. 750w is a lot of power on a bike. If the cables are getting too hot then they are simply too thin!

As a very fit cyclist (not pro or even close), I can put down 175w for 4 hours and that's working hard for 4 hours. 300w would be great! I could sip a mai tai and enjoy the scenery more!

pierce

If I do that middrive kit, I'll probably get the 750W version then run it at 36V where its peak 500W (it supports this). being able to fly up a hill while lightly spinning in a fairly high gear is awesome!

pierce

p.s. I'm a very out of shape 225 lb 64 yr old ... I doubt I could output 100 watts to save my life right now. I have been a fairly fit long distance cyclist in the past, but its been 20+ years.

pierce

sooooo. This thing overheats pretty quickly if you take it for a spirted ride. By the time I get to the bottom of the grade I live on, its so warm, its only outputting 250-350 watts even at full throttle. I can lightly pedal in H5 up the steepest part, doing 10-11 MPH, and in H6 up the rest, doing 15-17 MPH. this so beats grinding up that hill in granny gear on my ligthweight and sweating and panting.

I'm going to play around with the current limiter. it was originally set to 30A, effectively unlimited (the brick is rated at 26A output in 1000W mode), today I had it set to 20A, it didn't behave much differently. I think I'm going to try 10A, goal being to keep it from getting too hot. at 48V, 10A is 480 watts which is plenty of assist.

Today I took it for another 15 mile spin in town, riding hard on the throttle, lots of 'motorcycle' riding at speed today... I hooked the charger up to a power monitor (mFi Mini), its on the final legs of the charge, and has taken 480 watt*hours off the line so far. Its supposed to be 48V 18AH, 864 watt*hours.

its funny, when you're hard on the throttle the battery indicator will drop down to 2 bars, but you coast/pedal without power for awhile, and it would bounce back to all 5 bars. so the battery gauge isn't very useful. I apparently only used 50% today.


Best part of an ebike? I don't mind coming to a full stop at every stop sign... I drop 2 gears before I stop, then when its my turn, full power and pedal-shift-pedal-shift-pedal, cruise... heh.

MikeyMK

The pedal sensors are good. It's just do much better to ride PAS. I ripped my sensor when my chain came off, and had to use thumb shift - doesn't take long to get cramp and general discomfort. I can't see a twister being much better.

PAS is more natural, and means you have assistance when riding no-handed (for those of us who do).

Doc_Wui

Pierce, looks like the controller is in the bag. No air flow in there. I put mine out in the open air, clamped with a pair of u-straps to the frame. I used copper plated strap from the plumbing department at Home Depot, Painted them black later.

pierce

yeah, I bagged it for at least some protection against weather, probably not a great idea but its definitely not even remotely waterproof. I originally had temp mounted it on top of the rack, I might have to go back to that, and hide the big ugly bundle of wiring under some sort of plastic tube

powell

All the weight on the back ? Over rear wheel?
Not good idea.
Have you tried other locations for battery?

pierce

Well, there's nowhere else on that bike to put a battery that large other than that rack. even a smaller battery, if I had to mount it on the downtube, my wife wouldn't be able to step through, her hips and knees won't let her swing her leg over the seat.

yes, the bike is very tail heavy, but it doesn't have much of a tenancy to wheelie unless you really throw yourself back. hence my thinking mid-drive and water-bottle battery for my lighter weight hybrid build.

pierce

I agree, but the twist grip isn't that bad, I rode a motorcycle for 20 years and 80K miles. a thumb trigger throttle would definitely be annoying.

the "PAS" sensor that came with this kit is just a cadence detector, so the power it offers isn't proportional to your effort, its just an arbitrary albeit tunable (5 steps?) amount.

MikeyMK

Yeah, it only detects movement, but that's fine, you decide for yourself how much you wanna help the motor..

My grips are ergo, so twist no good for me. Thumb is great as a booster. Plus PAS is a legal requirement over here.

Can't you turn the rack back to front, any lower, or push the battery further forward? Anything to help distribution. Still, looks okay. Just powering up bumps could make the front very light. Tried imounting the rack on the fork..?

I agree on getting the computer out. Wires face down, they're fine. Mine have always been half covered, just a rain drip over the top, but wind turbulence cools it.

Whatever the details, that looks like a great little leisure/cruiser bike for her.

pierce

the rack pretty much has to be where it is, if its any farther forward (which it was when I first assembled it), its both quite tilted, and the Moxie suspension seatpost runs into the battery. also, i'm at the limit for wire lengths.

I've got some green, blue, yellow PP30 connectors coming in a couple days, when they get here, I'm going to rewire the controller, and take it out of the bag, bolt it to the top of the rack as far forward as I can. the controller really doesn't weigh much so doesn't impact the balance.

in spite of the rear weight, the bike does NOT have a tendency to wheelie unless you throw your weight back while whomping on the pedals... I just weighed the whole thing with a bathroom scale... me == 225. me holding bike == 288 lbs. QED, bike 63 lbs.


have I mentioned how much I hate JST-SM connectors? everything but the three main power wires and the battery leads are JST-SM, ugh.

Sean Rogers

I am interested in making my Hummer also. But it is a foldable type. Will it be a great thing to do?

pierce

huh, thought I'd already replied, must not have submitted

anyways, on a folder, I do believe I would use a mid drive, like a 350-500W TSDZ2, https://www.amazon.com/TongSheng-Ver.../dp/B01JP6M3AE (but undoubtably available elsewhere cheaper).

a 36V 'water bottle' battery pack would likely fit on a folder if it has a bottle mount... It might be a little tricky running the wiring past the hinges.

Doc_Wui

Let's see a pic of this "Hummer". I've done two light weight folders. Bought a heavy weight one.

Yes, you have to put in cable slack so you can fold the bike. First time I folded mine, when I unfolded later I found I had stretched out the throttle cable and pulled the connectors apart.

pierce

btw, I *highly* recommend using spiral cable wrap on any such cabling....






(yes, I added the headlight wire after I wrapped the rest, so now I need to redo it)

MikeyMK

I'd use a hub for a folder, as it's more space efficient. The small motors are nowhere near as heavy as the large ones, because they're a casing containing a pair of dril motors, whereas the large hubs are actually one big motor with the windings around a cast iron wheel.

Depending on the design of the bike, a thin rack battery might be best, as it can stay on the bike when folded. Some 10ah 36v batteries are really compact now, and that's a lot on a folder.

DucHuy

I really like a bike like this because it's convenient for me when traveling at a close distance but I can't afford it.