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Andres

Here's what the install ends up looking like on my . I haven't cleaned up the zip ties yet because the battery is only temporary (I'm going to get a smaller one that fits better).

Instead of the standard anchor bracket, I screwed a chain tensioner into that anchor bolt hole (cycles.eco/collections/tsdz2-a) because eccentric bottom bracket + chainstay. There's some foam protecting the frame in case the motor moves.

Drivetrain side of the bottom brackets/crank. The new tsdz2 chain guard and cranks are black and shiny. There's a rusty old (power grips) pedal installed. There's a small cog peeking out from the chainring/guard at 8 o'clock, which pushes against the chain to keep it from being loose and falling off.
Zoomed in on the underside of the bottom bracket/motor, non-drivetrain side. You can see the small chain tensioner cog bolted into the motor. The Motor hangs down below the bottom bracket, under the white frame. There's some cables bunched up under there, too, and sloppily zip-tied.
Zoomed in on the front of the motor, again non-drivetrain side. The black motor hangs below the frame, and nestled between the white bike frame and black motor is a piece of grey (partially crushed) foam. Another unclipped zip tie is on the frame, holding a (not visibe battery) cable.
Non-drivetrain side, zoomed out, viewing the bottom bracket/motor. The chainring is in the background, the motor hangs below the bottom bracket, and there's another rusty old pedal attached to the brand new crank arm. Sloppy black zip ties hold motor wires to the frame. There's a black eccentric bottom bracket visible that the motor is attached to; the bolts for the eccentric BB are visible over the motor's silver lock ring. The eccentric BB is adjusted so that the bottom bracket is at 6 o-clock, because the motor is expected to be installed in a normal bottom bracket with minimal space between the BB shell and BB.
#BikeNerdStuff#BikeTooter#EBikeConversion
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Andres

You can see the bolt hole that I installed the chain tensioner into here (second pic): social.ridetrans.it/@Andres4NY

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Andres

This motor feels just like a Bosch mid-drive (at least on the Cetma, w/ 48V battery), btw. I thought it might feel different unless I installed the open source firmware or made tweaks, but it just feels natural (right down to feeling like you're pedaling through molasses when the motor shuts off due to hitting the speed limit).

I'm super impressed. It's only a $300 motor.

The throttle feels terrible, though, so I'm going to uninstall it. Wife and I agreed we don't need it.

kevinschaper

@Andres4NY omg, the throttle ramp up is SO slow, and as soon as you touch it, the bike stops doing the torque sensing.

I was curious if you did the open source firmware. I shredded my nylon gear (big hill, not a surprise), and replaced it with metal and it worked pretty well after that. I’ve been tempted to buy a pre-converted open source one.

Andres

@kevinschaper Yeah, the funny thing is they sent me the wrong throttle so I waited an extra week for the replacement before doing the install. I should've just finished the install earlier and skipped the throttle!

I might do the open source firmware at some point, but so far no plans. Other improvements (like a new rain cover/new box, and new brake calipers) are much higher priority.

kevinschaper

@Andres4NY I also have still never found a good place for the battery on my Cetma. Under the bench was ok till I took the bench out, behind the box is bad because the battery won’t come off. It would be nice to find something that could fit inside the main triangle (quadrilateral?).

Andres

@kevinschaper I'm shopping around for batteries. I'm going to install the current one (Hailong G70) elsewhere; likely on the bottom of the Kombi's downtube. I have some leads on different sized batteries that might work, but need to do more research.

Andres

@kevinschaper So UPP has a bunch of different sizes and shapes (aliexpress.com/store/110082555 , with their US stock also on amazon.com/s?me=A323YRGVBR4QGU). I was hopeful that I could fit one of the silverfish or rack batteries, but they just don't fit. I also have the extra restriction that I want to be able to pull out the battery without a hassle, which means no triangle batteries (100 velcro straps) or square batteries (unplugging wires).

The only thing that'll fit appears to be their bottle batteries..

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Andres

@kevinschaper ...which are limited to between 7A and 10.5A at 48V. But given how awesome some of them are (battery plugs into the bottle cage, the bottle cage is attached & wired to the bike), I'm thinking it might make sense to just have multiple < 10A batteries that I just plug in when needed. Longer trip, bring an extra battery? aliexpress.com/store/group/48V

login.aliexpress.comBuy Products Online from China Wholesalers at Aliexpress.com
Andres

@kevinschaper I decided to keep the G70 hailong battery shared between the bikes, but installed off to the side like so. There's a key lock on one side and the power button on the other, so if it were centered one or the other would be unreachable.

This Cetma came with a Luna wolfpack battery, which was strapped where the back of the box is. During rides it shakes up and down and bends the plastic platform; this is a lot more stable since it partially rests on the metal frame.

top-down view of the back of the cetma box. Inside the box are some orange pumpkins. Behind the box but in front of the steer tube is a black hailong ebike batter. It kinda looks like it's hanging off the edge of the bike.
view from the back of the same battery/bike. Here you can see that the back of the battery touches the steer tube, and extends left from there (parallel to the back of the bike box).
The battery is gone now, but the battery mount is visible where it once was.
close-up view of the battery mount, showing how it's screwed down to the black plastic platform.
Rik @ bikescape.org

@Andres4NY I really like the torque sensing - makes it so easy to get going from a dead stop. The throttle is rather useless but I’m keeping mine in case I get in a situation where I can’t pedal (bad left knee acts up sometimes).

Rik @ bikescape.org

@Andres4NY Looks great! Right now I have my battery tucked behind the saddle and rear rack. It will either end up on the box platform or on the rear rack.

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