StefEbike for my wonderful disabled wife

[thundercamel]

I need to get updating this year! I did some maintenance for the season on both bikes, though my wife's StefEbike only needed about 10% of the work. Cleaned and lubed both chains, do people actually lube shifters and cables like the manual says? I only read about that yesterday, so I suppose it couldn't hurt.

My bike now has new tires, new tubes, the new rear wheel and motor Ebikeling sent me, new 11-28 tooth DNP gearset, and I shimmed/adjusted the handlebars and seat for more comfort and no wobble. I like the Marathon Cross tires a lot, and the bike overall is better than last year, but my center of mass is still so damn high through the turns Even my relatively low cadence lets me keep assisting the motor cruising at 24mph, so my battery life is better now at those speeds, though still less range than if I limit the speed to 15mph. I still have yet to try the possible regen input I wired to the EBS pad in the controller, mentioned on the first page...

My family got to enjoy a trip to the Independence Grove forest preserve and a park hopping in the neighborhood All images can be opened in a new tab for full resolution.

My son helped me by fishing for tools

Shiny! (for now)

Still brown so far around here

My son is now 3, and his attitude has now changed to more of a "let's get going mama!" His smiles and giggles are directly proportional to the speed at which he's traveling, which confirms that we were stopped at the time of this picture.

These geese sitting on their nests last week must be currently covered in snow. I was wearing shorts recording this for goodness sake!
[youtube]SPd5o2Vu0xI[/youtube]

 

[thundercamel]

My oldest nephew stayed at our house over the weekend. The weather was too nice on Sunday to not ride the trails! Unfortunately my wife was feeling under the weather yesterday. She dropped the three of us off at the trailhead and we rode ~20 miles home. My son enjoyed counting all the dogs he saw

I heard a lot of comments like, "That's a cool seat!" "I've never seen one like that before!" and one of the bikers that I passed said, "You're fully loaded!"

The last hill to climb before my house I was going to sneak behind the buildings, but a full car with windows down was ablaze with chatter like "look at all that!" There was a green traffic arrow, so I took to the road instead, and in typical fashion for my bike it shut off since it was the last hill again, lol!

Usually at this spot the battery voltage hits my conservatively high pack low voltage cutoff, which I need to lower. This time, the smart BMS temperature sensors hit my high limit, so I need to get used to unzipping my triangle bag for breezy ventilation now that the motor controller is in there and the days are warmer.

 

[thundercamel]

Changed the StefEbike handlebar to a North Road style, and sacrificed the placement of the rear shifter to make the throttle more comfortable. I'd like to switch both bikes to trigger shifters and try twist throttles when funds aren't as tight. The wife likes the upright riding position, and less pressure on her wrists.

 

[thundercamel]

On the controller, I can see a pad on the board marked "EBS" with no wire attached. It may actually be capable of regen but just doen't have the wires hooked up. The layout looks like the typical "Infineon" style, but hard to say based on just the looks.

So I finally tried out the EBS pad on my bike's controller in an effort to find regenerative braking. Fechter suggested I check it out, and I've found some references in other threads as well. When the controller is on, the EBS pad floats to 5 volts. Pulling it down to ground does not initiate regen, nor does it enable the brake levers to initiate regen. In fact it exhibited no behavior other than making the motor jump forward every time a brake lever was released. Totally bizarre!
2022 UPDATE: Connecting the EBS pad to ground DOES enable regen!

I'm going to have to do more research and get a further understanding of this controller. I already have a couple Infineon threads to read, but am open to suggestions :wink:

Infineon Controller Technical
XPD: open-source keywin e-bike lab replacement

 

[thundercamel]

I finally got to rebuilding the StefEbike battery, because I never liked having the second rack over the rear wheel. Making the aluminum battery box has been the most difficult part, using a jigsaw, vise, hammer, drill and tap. Pictures galore; open as a new tab for full resolution:

Designing an arrangement with the hexagon pattern was fun!

Pulling my negative wire straight down earned me a boo boo. I layered another nickel strip over that.

Tried to actually lay out the BMS wires nicely this time and tape everything down. Still haven't bothered to test the PTC fuses that I bought for each BMS wire.

All the parts of the box that I ended up with:

Drilled and tapped six of these to hold the side panels on.

I showed my wife a few choices on vinyl, and this was her favorite

I forced myself to install the 48/36/26 crankset since I wouldn't want to remove this box later to adjust the shifter/derailleur. I'm not sure if the derailleur is supposed to match the chainring size, but I could BARELY get it set to work with all three gears. The original was a 42/34/24. I had to chop the front of the derailleur off so it wouldn't hit the battery box; I don't even know why that's there? The chain only ever touches the lower portion.

Empty box:

Full box, and I still hope to tuck all these wires and plugs in around the edge

 

[thundercamel]

How this project has been going so far:

What is further delaying this project:

 

[thundercamel]

Went for a brief ride in the rain last night! It's definitely got a little more kick to it without as much voltage sag, and the basic battery life LED's don't droop to red whenever you're on throttle anymore. Even though the goal was to get rid of the rack over the rear wheel, we had gotten so used to it that now it looks like something's missing!

Still need to mount the rear tail lights and fenders on both bikes. I'm interested to see how the vinyl will look in direct sunlight, and how the battery temperature will be. With the larger chainring and cleaner overall look, this thing looks made for speed

 

[pwd]

Nice work on the new pack. What cells and what cell holders did you use?

 

[thundercamel]

Absolutely beautiful day yesterday! My wife liked the increased power of her bike, and it looks great! We encountered a pre-built fat tire ebike, which I blew by on the uphill as a demonstration of DIY superiority. He was friendly and we all chatted for a few minutes

It looks like I forgot to mention on here that I got my friend a pair of CEmoto folding ebikes for practically free. A friendly guy I met last year on the trails first asked if anyone wanted to buy a pair of broken ebikes. I ended up helping him diagnose the problem, but by this year he said they were just taking up space. I threw him the $47 in my wallet and gave them to my friend for his birthday! The cheap 2000 mAh cells dated 2013-12-20 had built up too much internal resistance to spin the wheel barely. My friend bought replacement MJ1 cells and I welded it up for him. It helps him up the hills, but the geared motor stops drawing power around 18mph, we think from back EMF. I'm considering changing the battery from 10s4p to 14s3p, modding the BMS and controller, and seeing what that does.

 

[thundercamel]

Nice work on the new pack. What cells and what cell holders did you use?

Thanks! I need to update my parts list in the first post, but the cell holders are these in both 10P and 13P from aliexpress, and the cells are the same LG MJ1 cells from last year. I just removed the 3.5 amp vruzend caps to make a honeycomb/hexagon spot welded arrangement. I did glue everything with this glue, that another member recommended.

 

[qwerkus]

Love the work. Very inspiring. But are you sure you want to go V Brakes only with that huge motor ? Sounds very dangerous to me, especially when it starts pouring.

 

[wturber]

Love the work. Very inspiring. But are you sure you want to go V Brakes only with that huge motor ? Sounds very dangerous to me, especially when it starts pouring.

Ya know. Somehow I managed to ride bikes for decades and always managed to stop in time using rim brakes. I did the same as a kid with my one speed coaster brake equipped Schwinn Typhoon as well. It was a simple thing. You adjust how you ride to what the bike can do. Riding without a good understanding of and consideration for your bike's stopping power is what is dangerous.

I agree that disc brakes are better in wet weather. But I always just gave a slight press to my rim brakes to squeegee the water off and all was good. And if the conditions were really wet and that didn't work well, I just slowed down - which made sense because the tires would have lower traction in the wet and visibility would typically be worse as well.

 

[Chalo]

Love the work. Very inspiring. But are you sure you want to go V Brakes only with that huge motor ? Sounds very dangerous to me, especially when it starts pouring.

Ya know. Somehow I managed to ride bikes for decades and always managed to stop in time using rim brakes.

Yep. From all the hype about discs, you'd think they don't get wet. But they do, which makes them noisy and changes their braking characteristics for the worse. Coaster and drum (and electric motor) brakes are unaffected by rain, but all the rest of them require accommodation by the rider because their performance changes when wet.

Like you point out, it's not necessarily a good thing to have strong braking when you have weak adhesion between the tire and the road surface.

Also, not all disc brakes are strong. I work on weak ones pretty often. Yesterday I replaced pads and cleaned rotors of some OEM Promax discs that became better after servicing, but did not become good.

 

[thundercamel]

Thanks! Both of our bikes have v-brakes, and I have them dialed in to be tight before the lever hits the handlebar. They can emergency stop pretty well. They're only used for leisure, so my wife has never gotten caught in the rain, and I have twice. Got soaked, and I didn't notice any problems stopping, but I don't push turning or stopping performance to the limit; just battery range gets tested regularly.

I did briefly test the disk brakes that came with my friend's CEmoto bikes, and I would say they were better overall. We do laugh at the occasional squeak they make vs. the occasional squeal of my rim brakes. I just won't spend the time or expense when our forks don't have caliper mounting points (not sure how the rear mounts) and these aren't all weather performance machines.

 

[neptronix]

Wonderful bikes, mate! I love the large self built batteries in particular.

You are doing your family a great service by keeping them physically active.

 

[thundercamel]

Wonderful bikes, mate! I love the large self built batteries in particular.

You are doing your family a great service by keeping them physically active.

Great to have you check out my build thread

I appreciate all the comments from everybody! We will be riding with some friends in Wisconsin tomorrow.

 

[thundercamel]

Holy moly, we got a 5 day old baby foster girl placed with us yesterday!

 

[wturber]

Holy moly, we got a 5 day old baby foster girl placed with us yesterday!

Lucky girl.

 

[thundercamel]

Lucky girl.

Thanks man! She's been a good girl, and my son is stuck to me even more than before

I rode to work for the first time today! 20.0 miles all on public roads, which is why I was hesitant to try before. At first I just left the throttle at 100%, but didn't want to risk the battery coming up short, so I settled into my 26mph pedaling speed. The trip is normally 45 minutes with traffic, and sometimes 52 minutes on bad days. It took me 52 minutes biking with a few checks of the map on my phone, so I can get that time lower now that I've done the route, and can push the battery a little further.

 

[thundercamel]

And here was my ride home Friday. Since the battery was hot off the charger, I used more of the throttle on the downhill sections where my pedaling couldn't keep up, and for the last third just left the throttle at 100%. Even though I was moving faster, the afternoon had way more traffic, and crossing roads took longer waiting for a gap. The trip ended up taking 52 minutes again, just like the morning.

I'd like to do this more often, but the motor was pretty toasty. I'm going to get some statorade for sure, but I do have a spray can of insulating varnish to apply first. It would also be nice to replace my 48t chainring with a 60t so I could keep assisting the motor at high speeds, but I'd like to keep my front derailleur functioning for when I ride with non e-bike friends. The largest 5x100mm ramped chainring I can find is 53t, and it's flat while my original looks to be offset.

Also my wrists and throttle thumb were sore for a couple days afterwards

Open images as a new tab for full resolution:

 

[wturber]

And here was my ride home Friday. Since the battery was hot off the charger, I used more of the throttle on the downhill sections where my pedaling couldn't keep up, and for the last third just left the throttle at 100%.

Perhaps consider just coasting on the steeper downhills to conserve battery and let the motor cool down a bit. I use about 150 watts max when going downhill and zero assist once I'm going faster than 28 mph.

You are spending a lot of time near 30 mph. Make sure your brakes, tires and the rest of the bike are top-notch working condition. And be especially vigilant for motorists and road debris at those speeds. It may feel great, but you are likely pushing the limits of what the bike and normal human reflexes can reasonably handle. Personally, I've settled on target road speeds of 25 mph and only go much faster (36 mph or so) on relatively brief downhill sections. If you have to do something in a panic at 35 mph, you may find the bike isn't quite up to the task.

 

[thundercamel]

This is all very good advice, and 26mph does seem to be my comfy high speed as my bike currently stands. That first trip was mostly a test of how quickly I could make the commute compared with driving. I did receive some statorade to hopefully keep the coils healthy if I do this on a regular basis. Road debris I was able to see far enough ahead to avoid easily enough. My biggest concern is having to hope that motorists give me a little room for the few sections where pavement doesn't extend past the white line at all.

I got a never used 700c suspension fork with disk and v-brake mounts for super cheap on ebay, even though I knew the steerer tube wouldn't be tall enough for my frame. The tube looks to be pressed into the fork, and I do have a hydraulic press... I'm afraid the tube has a flare at the base that is custom to SR Suntour. I also read a claim about RockShox being a one time press design, and becoming damaged if you press out the tube. Still, there's a chance I could get it working, possibly with a shop welding in a section of the same size tubing near the bottom.

 

[2old]

There's a big family that depends on you; messing around with the steerer of a front fork seems risky. Check Amazon for inexpensive alternatives that, while not superb, should suffice for road or light off road.

 

[thundercamel]

Of course I did that first. The only compatible result was this. If it doesn't even have a disc caliper mounting point, I'm not going to bother.

The other option is to buy this and convert my headset to threadless, which would be another expense.

My family trusts my ability to safely inspect and work on my bikes and cars.

Here's an example of the welding I mentioned: [youtube]HNbJ9dadNYo[/youtube]

 

[thundercamel]

I did ride a few more times to work (20 miles each way), and felt the need to try out my wife's StefEbike for the trip. Even though it's too small of a bike for me, it's a nicer experience, lol! I believe it's the fatter tires that I mostly like, and handlebar second.

From an electrical standpoint with the same battery between the two bikes, hers is way more efficient. The controller draws 26 amps as opposed to 30, and the motor winding starts to hit back EMF around 30 mph and current draw starts to drop. I never had so much state of charge remaining when I got to work! I was looking forward to a full throttle ride home with the knowledge that there was no way I could drain the battery. Of course, three miles from work directly after the busiest road I have to cross, I nailed a pothole in the tiny section of gravel road I go through as I was turning my head back forward and got my first pinch flat ever.

Thankfully my friend was available to pick me up. I put a patch on each hole, but the next morning it was flat again, so I must have done something wrong. Since the tire is getting worn anyway, got a new beefy tire for the rear, and some puncture resistant tubes. Holy moly, those tubes are beasts! Even the box they came in is three times the size of normal tubes! I'd like to confirm that people like Neppy are using these when they still have puncture issues, because this combined with the new Marathon MTB tire seems invincible!

Also picked up a new to bike to experiment with: