Supertux's Second E-Bike: Yet Another BBS02

Supertux1 · Jul 18, 2014

Knowing nothing about bikes, I bought this Motobecane 29er two years ago (2012) to be the basis of my first e-bike.
I rode it hundreds of miles while waiting for parts for my first ebike and discovered it was not the optimal platform for a commuter ebike.
Eventually I bought another bike for that and that build is detailed here: http://endless-sphere.com/forums/viewtopic.php?f=6&t=51147

After a few thousand miles on my commuter bike, I brushed the dust off this 29er and made it an awesome "dirt" bike.

I had to remove some nice hydraulic brakes in favor of the cheap Chinese cable pull handles, but replaced those with BB7's and bigger discs so it's all good.

I replaced the Bafang BBS02 thumb throttle with a half-twist throttle so as not to interfere with my shifters. I pulled apart the BBS02 thumb throttle and it's a hall sensor type. I chopped the funky Bafang connector off it and spliced it into the half twist from ebikes.ca. It works. Now my controls are the same for both ebikes.

The sprocket I have is a 10 speed SRAM (PG-1070 I think) in the range of 11-36T with a KMC 10 speed chain with a 'MissingLink' connector.
I drove this straight up a very steep hill in granny gear #3, no pedal, the motor and gears strained, but no problems. Top record speed has been
31mph which is the limit built into the controller/display (50kph). It could go faster.

I suspect the Bafang BBS02 is labeled at "750W" for legal reasons, but it is capable of so much more: (Theoretically: 58v @ 25A = 1450 W)

Indeed this one is limited to 25A:

Even with all my shenanigans riding up grass hills and whatever else 'off road' I could find on the way to work,
this is still more efficient than my MAC 10T geared hub motor under the same conditions. 10 miles / 200Wh = 20 Wh/mi:

Here's a complete parts list: (TL;DR Price: $2521)
(Not including shipping or special bike tools needed to make bikes, zip ties and other small stuff

Supertux1 · Jul 18, 2014

Future Plans:

o Reverse engineer the serial protocol between the C961 display and the controller unit.
Emulate C961 display with an Arduino with inputs for brakes, speed and throttle.

o Find out where the speed limit is enforced, remove it. Controller? Display Unit?

o Crack open the case and add a temperature sensor to the coils, draw out JST-SM terminated leads for PAS, controller power on and throttle.
(If possible, controller is 'potted' in resin and may not be accessible, may have to tap into wire harness.)

o Integrate a CAv3 DPS / remote shunt into the system.

o Possibly add an IGH (Nuvinci N360) to the rear wheel. Maybe. Might be too heavy for dropping rear wheel off cliffs.
Add servo control to IGH. Interface servo with Arduino, handlebar mounted electronic 'shifter' (or Automatic based on current, speed, throttle etc...

)

spinningmagnets · Jul 18, 2014

18,5-Ah? Daaaayum!

At a your logged low amp-draw, that pack will never get warm, much less hot. It should last years...

Supertux1 · Jul 18, 2014

spinningmagnets said:
18,5-Ah? Daaaayum!

At a your logged low amp-draw, that pack will never get warm, much less hot. It should last years...

At 14s9p, I've never had this pack warm at all. It's already two years old and still has a lot of life left in it. I expected 3 years but it's going to have a much longer serviceable life than that. I guess charging to %90, discharging conservatively between charges and not beating the crap out of it pays off!

This battery also goes in the MAC 10T build and has a max draw of 30A there. (MAC overheats (80 degrees celsius) long before battery gets low.)

The new mid drive will be even gentler on it.

Range test this weekend, hoping to beat my MAC's best record of 45 miles.

I will be sad when I have to retire this battery but I am sure it's replacement will be even more awesome.

Supertux1 · Jul 18, 2014

Although not strictly electric in nature, I added my standard anti theft / anti flat / no fail braking / comfort system to this bike as well.

Pinhead Locking Skewers on the front, seat and rear tires:
o In addition to giving more security, they are unlikely to loosen like a standard skewer with a lever might.
o Requires a special tool to remove or loosen the bolts.

Rhinos Dillos Tire Liners + Slime Tube:
o I have added these to four bikes, my two ebikes, gfs' eMotion ebike and her normal bike and have yet to get a flat on any of them.
o Adds weight, but who cares! Electric!

Avid BB7 Brakes:
o The best mechanical brakes money can buy and field serviceable.
o Won't interfere with most hub motor covers.
o Pair with 200mm rotor on the rear and 180mm rotor on the front for maximum stoppage & heat dissipation.
(Did You Know? Front forks have a maximum disc diameter rating.)

Ergon GP2 Handle Bar Grip:
o Ergonometric grip supports you palms for long rides, no carpal issues.
o Side horns let you change grip to avoid cramps.
o Easy to saw off a chunk of the right hand grip to make room for half twist throttles.

I put a comfort seat that is split down the middle and bends to my butt shape on it.
I am debating putting another suspension seatpost (Thudbuster / Thudbuster ST) on this bike. Most of the time I ride it standing on the pedals.

ebikesvi · Jul 21, 2014

Thanks for the specs, I've got a lower end Motobecane Fantom and waiting for a BSS02 to arrive for my first bike build.

Did you consider any means of using the hydraulic brakes? I guess BB7 200s will do but I've got a couple 15 degree plus hills to negotiate and hope to try the hydraulics.

Haven't got a Nuvinci on order yet but think I'll want it. I don't do a whole lot of dropping the rear wheel off cliffs these days.

Charlie

Supertux1 said:
Knowing nothing about bikes, I bought this Motobecane 29er two years ago (2012) to be the basis of my first e-bike.
I rode it hundreds of miles while waiting for parts for my first ebike and discovered it was not the optimal platform for a commuter ebike.
Eventually I bought another bike for that and that build is detailed here: http://endless-sphere.com/forums/viewtopic.php?f=6&t=51147

Supertux1 · Jul 22, 2014

ebikesvi said:
Thanks for the specs, I've got a lower end Motobecane Fantom and waiting for a BSS02 to arrive for my first bike build.

Did you consider any means of using the hydraulic brakes? I guess BB7 200s will do but I've got a couple 15 degree plus hills to negotiate and hope to try the hydraulics.

Haven't got a Nuvinci on order yet but think I'll want it. I don't do a whole lot of dropping the rear wheel off cliffs these days.

Charlie

There's lots of ways of getting hydraulic brakes to work, most require building a switch into the brake pull which adds
complexity and something else to fail/maintain. Hydraulics are great, but if you ever have to open one up it can be a mess and a bleed kit is necessary. I like the simplicity of being able to adjust my brakes on the road with just a simple multi-tool.

There are some commercial options as well, but seem to be OEM-only, eg: http://www.tektro.com/_english/01_products/01_prodetail.php?pid=155&sortname=Disc&sort=1&fid=1
(You may find them on eBay sometimes too.)

With hills the issue isn't how the pads get compressed but more how your rotors and pads deal with the heat.
Bigger better rotors are the best solution for that.

The thing that is currently discouraging me from the Nuvinci is the weight of the thing and the shifter design.
I have a hub motor in my other bike and it gets slammed pretty hard when the wheel drops.

Kepler · Jul 22, 2014

Nice build. Well done.

Curious about the 14S9P 18650 battery set-up. With the BBS factory set to 41V LVC and adjustable to a max 43V, do you ever hit this voltage? Also do you know what the BMS LVC is set to on a 14S 18650 pack?

I want to build an 18650 pack for my BBS drive but aren't sure whether to go 13S or 14S. 14S with 43V cutout is just under 3.1V per cell as compared to the 13S with a 41V cutout being 3.15V per cell.

Supertux1 · Jul 23, 2014

Kepler said:
Nice build. Well done.

Curious about the 14S9P 18650 battery set-up. With the BBS factory set to 41V LVC and adjustable to a max 43V, do you ever hit this voltage? Also do you know what the BMS LVC is set to on a 14S 18650 pack?

I want to build an 18650 pack for my BBS drive but aren't sure whether to go 13S or 14S. 14S with 43V cutout is just under 3.1V per cell as compared to the 13S with a 41V cutout being 3.15V per cell.

Thanks! This was a very simple and (relatively) cheap build, no wheel lacing etc...

I think it took me about 2 hours to slap everything on and go for a quick test ride.

Issues so far have been that the bolt holding the left crank on is not reverse threaded so it wants to undo itself all the time.
I've really got to crank tight on it to the point where I think I might be in the bolt snapping zone. I've tried blue loctite.
Next will be a different bolt, maybe a lock-washer (nordlock) and finally red loctite. :shock:

(Please talk me out of this one.)

I don't know if my chain is the right length. I didn't add or remove any links to it. For the first few aggressive rides I had
an issue of the chain falling off to the inside or the outside between the ring and the guard when making gear changes.
I solved this issue by putting the original front derailleur back on and setting the stop screws to make it not move. It drags
on the granny gear because the chainline is angulated so much but it's not a huge issue, just an annoyance. That solved the
chain falling off issues.

I never ride my packs anywhere near LVC in regular use so I honestly don't know what the lower limits are of the BBS02 or the pack.
( I don't have a programming cable or software for the new BBS02 yet. ) The datasheet for the cell has the minimum discharge cutoff voltage at 2.75V, which would be 38.5V in a 14s and I think that's way too low. This is the same datasheet that says it's a 10C cell and that's BS, so proceed carefully... The 3v lipo rule is probably best and that would be 42V, on my CAv3 equipped bike I have the CAv3 LVC at 46 volts.

Last weekend I rode it until either the BBS02 or the BMS turned things off and that was at about 46 volts too. I wasn't able to look
at my watt meter in real time so that was a stopped no load voltage. I think once you get down to 46 volts no load, heavy 25-30A amperage draws can pull it down into that low 41/42/43V range where things start to trip. These cells can be drawn on heavy but will drop the voltage quite a bit under load.

It's probably not a good idea to always rely on your BMS / BBS02 LVC to tell you when your ride is done anyway.
You generally want to quit well before that to preserve the pack integrity and longevity.

Get the 14S pack, it'll charge up to 58V or so fresh off the charger which is just under the limit (60V-ish) of overvolting most 48v stuff.
For many miles you'll get the benefits of a few extra volts (more speed) which is noticeable. I spend the majority of my time riding at about 55V.

Kepler · Jul 23, 2014

Keeping it simple is what its all about with these drives.

Got no idea why your left-hand side crank bolt is coming loose. With tapered cranks you shouldn't need a left-hand tread on the left side as it is just pushing the crank onto the taper. Mine have never come loose but I do lean on them hard when tightening the bolts up. Definitely don't use red loctite on this component.

Looking at your picture, the chain length looks fine. The locked out front dérailleur is a must though.

Thanks for the feedback on battery cell count choice.

ebikesvi · Jul 24, 2014

Thanks for the reply, I was considering the steepness issue as one of finger fatigue as well as stopping capacity. I have a Currie Metro with BB5 / 160s that I took down the hill and those were smoking the brakes by midway down so I slowed to a crawl and vowed to look for something with both higher stopping capacity and less finger strain for regular use. Ability to maintain on the road is also a big consideration so maybe I'll look at the 200mm BB7s. I think I'll try the installed Tektro 180 hydraulics on the BSS02 build first to see how they compare against the Avid BB5 160s as a next step. Also look forward to trying going up the steeper slopes with the BSS02.

There's lots of ways of getting hydraulic brakes to work, most require building a switch into the brake pull which adds
complexity and something else to fail/maintain. Hydraulics are great, but if you ever have to open one up it can be a mess and a bleed kit is necessary. I like the simplicity of being able to adjust my brakes on the road with just a simple multi-tool.

There are some commercial options as well, but seem to be OEM-only, eg: http://www.tektro.com/_english/01_products/01_prodetail.php?pid=155&sortname=Disc&sort=1&fid=1

Supertux1 · Jul 26, 2014

I found the issue to my crank always getting loose, it wasn't on far enough because of the anodizing / paint where the parts mate so while riding it would work it's way loose.

I scraped some of it off on both sides and we'll see how it fits now.

Adding the front derailleur back has held up great, no issues.

Supertux1 · Jul 30, 2014

Here's a riding video showing a good mix of trail, bush-wacking, and some on road performance.

[youtube]5zkaDKd9-MY[/youtube]

Supertux1 · Jul 31, 2014

I'm going to try winter riding with this one.

Here are my future tires:

http://www.schwalbe.com/en/spike-reader/ice-spiker-pro.html

scfoster · Dec 13, 2014

Supertux1 said:
I found the issue to my crank always getting loose, it wasn't on far enough because of the anodizing / paint where the parts mate so while riding it would work it's way loose.

I scraped some of it off on both sides and we'll see how it fits now.

Adding the front derailleur back has held up great, no issues.

I'm facing the same issue with the left crank coming loose, so I'll take a look. Thanks.

Looks like the BBS02 is more to your liking for commutes over the Mac Hub. Can you give your opinion?

Switched to a smaller battery since my commute is only 5.5 miles each way (shown in the picture below). No point lugging the extra weight with the larger battery. Everything goes in the PakRak commuter bag with the PakRak seat post mount system, which is rated for 22lbs.

scfoster · Jan 10, 2015

Supertux1 said:
I'm going to try winter riding with this one.

Here are my future tires:

http://www.schwalbe.com/en/spike-reader/ice-spiker-pro.html

Did you ever get the studded tires installed?

Supertux1 · May 21, 2015

I got the studded tires and they worked awesomely after carefully breaking the studs in and provided there's not too much snow.

Rode it on the lake about 25 miles per hour quite safely, no sharp turns though.

Fat Bikes were out and like WTF?

10943699_10103949681922647_4928124834498512940_n_zpsmnmq6m5q.jpg

Supertux1 · May 21, 2015

scfoster said:
Supertux1 said:

I found the issue to my crank always getting loose, it wasn't on far enough because of the anodizing / paint where the parts mate so while riding it would work it's way loose.

I scraped some of it off on both sides and we'll see how it fits now.

Adding the front derailleur back has held up great, no issues.

Click to expand...

I'm facing the same issue with the left crank coming loose, so I'll take a look. Thanks.

Looks like the BBS02 is more to your liking for commutes over the Mac Hub. Can you give your opinion?

Switched to a smaller battery since my commute is only 5.5 miles each way (shown in the picture below). No point lugging the extra weight with the larger battery. Everything goes in the PakRak commuter bag with the PakRak seat post mount system, which is rated for 22lbs.

Sorry for the late replies I've been out of the scene for awhile, but still riding!
The pack is doing fine too, 2.5 years of hard riding and still enough to get me 10 miles to work.

Here's my thoughts on commuting with them both:

I like to ride both bikes WOT as fast as possible whenever I can because I'm impatient.

The BBS02 is a faster commute due to the gearing and 29 inch wheels. I hit 42mph with it down a hill once and even today 35 mph is possible on flat ground provided enough time to get up there. Has slick-ish 2" tires that I keep at 65psi for speed. It never overheats. I shift accordingly and I don't let off the throttle when shifting up or down. Always keep the chain clean and oiled. I broke a KMC quick link once. ($5) I think my cassette clutch is getting weak/noisy because it's not used to being driven up near vertical hills in granny gear @ 1500W. I have a lot more fun with this bike riding into work because I ride it 'wherever' without worry and it can keep up with traffic on the 25-30 mph roads.

Because I ride fast @25-30 Amps 50v, the MAC-10T has thermal problems around mile 8 of my commute and I have crawl along at 20mph or risk thermal shutdown from the CA. I've noticed that this bike is more efficient on the battery though because I have the CA set to regulate amperage, and I have a three position switch to only let it use 350W which is the sweet spot for 20mph cruising on slick tires (45 miles when the battery was new.) It's also got more cargo options with the rack and the upright handlebars are more comfortable for the long hauls, plus generator lights. It's like an ebike minivan, all it needs is an LCD TV.

Supertux1 · May 21, 2015

scfoster said:
Switched to a smaller battery since my commute is only 5.5 miles each way (shown in the picture below). No point lugging the extra weight with the larger battery. Everything goes in the PakRak commuter bag with the PakRak seat post mount system, which is rated for 22lbs.

I have a Toppeak seat post rack that I can fit on the BBS02 mountain bike if I remove the rear fender, so all my slide on commuting bags and
even a Toppeak rail grocery basket will fit.

I can throw a few beers in there, motor on over to my favorite spot, remove the rack and replace the fender and tear around because it's all levers and no tools.

Supertux1 · May 28, 2015

I just bought two of these in the 35c size for fun, red, because LOOK AT ME!:

http://www.amazon.com/gp/product/B00KXXH2SM

Supertux's Second E-Bike: Yet Another BBS02

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