Single-speed track stealth ultralight

You can do that, sure. But you are limited to rims that don't have alternating tilt or stagger in their holes, which is not very many of them. And when truing, you have in effect half as many places to pull on the rim-- the same basic problem as paired-spoke wheels.

You would run into the problem that paired-spoke wheels were designed to circumvent, which is the rim zigzagging from side to side when the opposing spokes are too far apart from each other.
 
Chalo said:
You can do that, sure. But you are limited to rims that don't have alternating tilt or stagger in their holes, which is not very many of them. And when truing, you have in effect half as many places to pull on the rim-- the same basic problem as paired-spoke wheels.

You would run into the problem that paired-spoke wheels were designed to circumvent, which is the rim zigzagging from side to side when the opposing spokes are too far apart from each other.

I also tried a 2 cross pattern, but it probably suffers the same flaws:36AlignedFlangeHoles2Cross.jpg
 
Thanks for the input. You guys had pretty much the same ideas I did today... I guess my options are:

  1. get 9 longer spokes and 9 shorter spokes with a length difference +/- the length of what the offset should be
  2. try to do a 1 cross or pseudo-radial lacing that may not be strong enough for Atlanta potholes
  3. try and get BMS Battery to send me a new motor or outer shell for my existing motor
  4. take the hit and get a different motor from another source

This friggin' sucks. I really don't want to have to have 3 different length spokes on my wheel so I can do a 2 cross. And I really don't think a radial lacing pattern would be strong enough to use for a daily commuter in Atlanta Ga. We have seriously shitty roads here. It's more like paved potholes rather than streets with some potholes in them.

I've emailed BMS Battery hoping that I hear back from them and they'll provide warranty service for this manufacturing defect.

Just so I can plan for the worst case scenario, what would a comparably small hub motor be? Are there any Bafang hubs that are around that 100-110mm size that are available from a US source?
 
Radially laced wheels are every bit as strong as cross-laced wheels, except in torsion. Your hub shell doesn't even allow true radial lacing, so the amount of torque that the small motor can put out shouldn't be a problem.
 
Good news!

BMSbattery is going to send me a new Q100H shell along with tools and instructions to change-out the defective hub shell for a good one.

I'm actually looking forward to having specialized tools for taking the hub apart; they may prove to be handy to have in the future. I know some people have made rigs to take these apart, so I'll post pics of what they send when they arrive for comparison.
 
That is good news indeed. Let us know when it all comes together.
 
BTW, there is one other option you didn't list: --redrilling one flange of the hub with the correct hole placement, in-between the existing holes. ;)

It'd be a bit weaker flange than usual, but I suspect it's strong enough to work fine like that.


(I redrilled my MXUS's flange for smaller holes than what it came with, so I could use regular bicycle spokes on it without washers or other bandaids to keep the heads from just coming right thru the giant holes it came with--no issues with the flange yet, despite the loads and potholes)
https://endless-sphere.com/forums/viewtopic.php?f=2&t=86180
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1261116&hilit=mxus%2A+spoke%2A+hole%2A+drill%2A#p1261116

Hopefully the new parts and tools they're sending you will fix the issue, but if not, you do have the above as an option. :)
 
Huh, that's a good suggestion too. I hadn't thought of trying to drill a new set of holes in the flange. It's good to hear that that technique worked for you. Hopefully it won't be necessary, but I'll keep it in mind.

While I wait for the new hub shell and tools, I got some other goodies for the build. My Phaserunner and the last bits I need to build the battery pack arrived, so I'll have some stuff to keep me busy while I wait to finish the wheel.
 
zro-1 said:
This may be useful to the rest of the forum: I was able to decipher the info printed on the motor casing. Here's what the motor reads:

AKM17062901002
AAD3620A
H


AKM = the manufacturer, Akiema (or however that's spelled)
170629 = the date of manufacture (2017-06-29)
01002 = The motor model and version (0100 = Q100, 2 = version 2)

AAD = I haven't been able to figure that out yet, but I believe it is the code for the style of gears/brakes the motor can use (freewheel + disk/rim brake)
36 = 36 volts (yeah, I'll follow that :D :wink: )
20A = 20 amps
H = the H-series of the Q100
I have two, recently purchased (12/2017) Q100H 328 - Both front hubs.
Gears - motor 15t / first stage planets 36t / second stage planets 23t / final ring 78t

Ratio = 8.139

AKM17092301002
AAD3616A-H
QC-PASS round sticker stating "16 Inches" (white/green)

AKM17092301017
AAD3616A-H
QC-PASS round sticker stating "16 Inches" (white/green)
 
That's great info Papa! Thank you for sharing it on this thread.

I got my pack welded and the BMS and solid state switched hot-glued in place. I'll post some pics of that in a few minutes.
 
OK, so here's the pics of the pack in progress...

First I used the very nice welder by Aulakiria to weld the parallel connections
IMG_0121.jpg

Then I knocked out the series connections
IMG_0123.jpg

I tested the voltage after the welding was done and the pack read at a nice steady 49.95V. I did test each cell ahead of time to make sure they were all ok, and every cell read ~3.64V (back when I first got the cells from Vruzend).

Next was placing the BMS and the on/off solid sate switch. I got the BMS from Vruzend as well, and I got the solid state switch from Luna Cycle.
IMG_0125.jpg

I still need to solder all the wires to the battery, but I'm going to wait till tomorrow after work to do that.


EDIT:
I took this pack apart and I did indeed damage the insulation on the batteries by welding the 3rd middle series strip. I got insanely lucky that I didn't weld a short into the pack and set my house on fire. DO NOT weld series strips in the middle of your cell pairs!
 
I got the BMS and on/off switch all wired in tonight. I verified the on/off switch is working correctly and I'm testing the BMS by hooking it up to the charger now.

IMG_0129.jpg
Wires all soldered on

IMG_0130.jpg
Closeup of the balance wires and primary discharge wires

IMG_0131.jpg
Charger port and on/off button

IMG_0132.jpg
Same, showing the button illuminated when the power is on.
 
Well. I got my battery shrink-wrapped and into the seat bag, and I hated it. It made the bike feel really top-heavy and running wires cleanly was going to be a pain in the ass. So... I decided I'd deconstruct it and make a backpack battery.

EDIT:
I think that a lot of my first impressions were due to the major change in rides. I was coming from a crazy-heavy old-school FS MTB with a BBSHD and battery on the down tube, to a super-light no suspension track style single speed frame. The ride was so different from what I was used to I think I jumped to conclusions about the battery being in a seat-bag. As I'd gotten some miles under the new frame, I realized that a lot of what I thought was the battery weight was just the change in weight ratio between myself and the bike. I mis-interpreted the nimbleness of the bike to the batteries tossing the bike around. By no means should you discard the idea of a seat-bag battery based on that one comment I made. I was probably very wrong. Back to the original post....

I recently got a really nice waterproof backpack from Timbuk2 that will perfectly fit a 13s2p battery down in the bottom of it. So that's what I'm going to do.

Here's the plan: newBatteryLayout.jpg

I'll post pics of it when it's done.
 
zro-1 said:
Well. I got my battery shrink-wrapped and into the seat bag, and I hated it. It made the bike feel really top-heavy and running wires cleanly was going to be a pain in the ass. So... I decided I'd deconstruct it and make a backpack battery.

Isn't moving the batteries even higher (onto your back) going to make the entire system -- you and the bike -- even more top heavy?
 
Yes. But the weight is on me, rather than being on the bike. With the battery pack in the seat bag it felt like the bike wanted to tip over more than I intended it to. If the weight is on me I figure my body will compensate better.

I know before I was saying that I already had a bunch of weight on my back and didn't want more, but after feeling the weight at the top of the bike (basically between my legs) I wasn't happy with it.

If I wasn't going for a stealthy build, I'd just toss the battery down in the triangle and be done with it, but I don't want a big battery in there.

My game plan now is to attach a magnetic connector to the bottom of the seat and have the battery in my backpack.
 
zro-1 said:
Yes. But the weight is on me, rather than being on the bike. With the battery pack in the seat bag it felt like the bike wanted to tip over more than I intended it to. If the weight is on me I figure my body will compensate better.

I know before I was saying that I already had a bunch of weight on my back and didn't want more, but after feeling the weight at the top of the bike (basically between my legs) I wasn't happy with it.

If I wasn't going for a stealthy build, I'd just toss the battery down in the triangle and be done with it, but I don't want a big battery in there.

My game plan now is to attach a magnetic connector to the bottom of the seat and have the battery in my backpack.

Struck me that you might fit your 26 batteries like this:junk.jpg. And if they were housed in some sort of semi-rigid container of the right color, it would almost disappear.

Then I guess it'd be whether you could live with a Q factor to clear an extra 20mm each side of the downtube.
 
I actually had considered that but gave it up pretty quickly.

  1. Its even more bulky/wider than a downtube battery
  2. It'll still look like I have shit strapped to my bike
  3. I'm tired of wide Q factors
  4. I wear a backpack anyway commuting and shopping
  5. I finally have a comfortable waterproof backpack that I don't feel puts a battery at risk
  6. There's now a magnetic connector in case I fall off the bike

Most of my previous concerns were with having something that could go into thermal runaway and burst into flames on my back, but with a BMS, magnetic connector, and a padded, waterproof bag, I think it should be ok. And nothing is more stealthy than a battery in a backpack. The only things on my bike will be the controller and motor.
 
Consider adding a rigid backboard to the long backpack battery... it will probably save you grief and only add a little weight and volume. Another trick is to wrap each cell in Scotch Shipping Strapping tape before gluing. Once you try it with a high temperature glue gun you'll see the mechanical advantage, plus it will improve durability and insulation between cells.

What part of Atlanta?
 
I got the backpack battery built. I'm very happy with the results.

Pics:
new-bat-1.jpg

new-bat-2.jpg

new-bat-3.jpg

new-bat-4.jpg

new-bat-5.jpg

new-bat-6.jpg

I also ordered both ends of a Rosenberger magnetic port for the discharge wire connection which will go under my seat. The connector is rated for 60V/30A and my battery will only be 54.6V (peak)/20A (max) so it should work perfectly. I couldn't find it on Luna any more, so I ordered it from Mouser. Here's the links if you want to get a set. It was $10 less on mouser than what Luna had been asking.

http://www.mouser.com/search/ProductDetail.aspx?r=476%2dC003%2d03%2d1000%2dC
http://www.mouser.com/search/ProductDetail.aspx?r=476%2dC003%2dB1%2d1000%2dC

I'm still waiting on BMSbattery to send me the replacement shell for the Q100H
 
Nice job that will work great in the water bladder section in a day pack,the last few days Ive been testing a 13s6p pack in a daypack the weight is inconsequential it does take up space so Im thinking for grocery runs to throw the 1/3 smaller 36v pack on the bikes back half rack for more pack space , problem solved.
For longer runs will carry one on the bike one in the day pack sharing the weight.
 
Yeah, this pack fits great in both the bladder pocket of my camelback day pack (vertically) as well as in the bottom of my timbuk2 laptop backpack (horizontally). It's a bit heavy with both my laptop and battery in the big bag, but the weight is nicely distributed, so it's not a huge deal. It feels like carrying around a 2nd gen iPad in terms of weight. I don't have a scale to weigh it with though.

I took a pic of the battery next to a 3s1p 5Ah Turnigy Graphine battery for size comparison (this is 13s2p 7Ah)
battery-size.jpg
 
Very small footprint , high capacity cells are the way to go. Im just using 2200 mah batteries so they take up a fair amount of space. 20 cells @ 36v is 4.4AH using 2200mah cells vs 7AH for 3500mah batteries
 
Yeah, 18650s have come a long way. This is 26 cells (but I know what you mean). I'm using LG MJ1's in my pack. I had shopped around and I found that getting them from Vruzend was the best bet for me. They are in Florida (so just 1 state over from me) so the shipping is much better, and they sell them in 2-packs for $9.99 (~$4.99 per cell) which when I factored in the shipping was the best deal in town for me.

Specs:
  • Nominal capacity: 3500 mAh
  • Nominal voltage: 3.635 V
  • Standard charge: 1.7 A
  • Maximum discharge current: 10 A
  • Cycles until 80% life remaining: 400 cycles

edit: All of the cells arrived between 3.634 and 3.637 volts
 
zro-1 said:
Yeah, this pack fits great in both the bladder pocket of my camelback day pack (vertically) as well as in the bottom of my timbuk2 laptop backpack (horizontally). It's a bit heavy with both my laptop and battery in the big bag, but the weight is nicely distributed, so it's not a huge deal. It feels like carrying around a 2nd gen iPad in terms of weight. I don't have a scale to weigh it with though.

It should be right around 2.5 lbs.
 
eCue said:
Very small footprint , high capacity cells are the way to go. Im just using 2200 mah batteries so they take up a fair amount of space. 20 cells @ 36v is 4.4AH using 2200mah cells vs 7AH for 3500mah batteries

Sure, but you probably paid $1.50 per cell. Factor in the capacity deficit, and you paid about half per amp hour.

The higher capacity cells are certainly the way to go for an ultralight/stealth (true meaning of the term) build though. Projects like this have me seriously thinking about electrifying my old Trek 1400.
 
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