Archive for the ‘Bikes’ Category.

Stabmixer – Electric Outboard Project

Ever since I was a kid, i wanted an electric outboard motor to use with a light rubber boat (without a hard floor). I actually even started experimenting when i was 12, but that didn’t work out at all.

Now, many years later, I wanted to give it a try again, my goal was a lightweight electric outboard, driving a chain inside a tube down to the propeller. Unfortunately, it all went wrong after I’ve made a prototype that was running the chain directly through the water. It worked so well, that I’ve decided to keep the chain outside. What I built is good for more than 1kw, but my intex excursion has it’s limits at around 6kph, which requires roughly 400watts.

The part’s I’ve used are:

Battery: 12s4p 18650 High drain (powertool) cells.
Motor: Chinese no-name Hub, good for about 1000w continues
Gear Ratio: 22×14
Propeller: JXF 15×13 / 381 x 330mm
Other Parts: Aluminium Rods, Steel Plates, Road frame parts, Buttom Bracket, Bolts, Nuts, Washers, Stem, Handlebar.

Be sure to check out the videos:

 

Blendwirkung V2 – The Uetliberg descent bike light

Blendwirkung V1 was a road light, that was built based on a Luxeon 1 LED (which was relatively new back then in ~2005). I have used it for a while, until I’ve decided that it was just too big and heavy.

Many years later, after I’ve moved my Magicshine from the handlebar to the helmet, and added the beautiful Lux-RC / Easy2Led Light to the handlebar. I began to think about a cordless solution on the helmet, as I really didn’t like the battery in the backpack, running a cable to the helmet. I’ve decided to go old school with this, and use NiMH, as I don’t want any LiXX battery on my helmet. This could be paranoid, but I just don’t like the idea at all.

 

 

I only use this light for the descent of our weekly Uetliberg-Run, so runtime wasn’t a big criteria.  I just wanted high output for about 20minutes on the existing 2/3 sub C NiMH cells that I’ve had lying arround. In the end I went for these components:

  • 2x Nanjg 110 Boost driver, ~950mA each – so Output is almost 2A
  • 1x CREE XM-L2 T6 4C LED – this is warm white, you gotta love it in the woods.
  • 1x TIR Optic, it’s either 20 or 25 degree, I don’t remember.
  • 2x 2500 mAh Sub-C NiMH high power cells.
  • Various Alloy sheet + part of an old heatsink

The light pulls arround 6Amps from the battery, which makes it difficult to find a good switch, since the one I initially installed was fried after about 10 toggles, I’ve removed it and don’t have a switch at the moment. It’s no beauty, but its brighter than most other lights I’ve seen on the Uetliberg, and it was most likely the cheapest as well. Have been using it many times – still love it. This light cannot be used stationary, as it needs some air flow to keep the temperature down.

BionX 250HT hub motor bearing replacement / disassembly, reassembly

The bearings in my BionX hub motor began to die at around 6500km, and now completely worn out at around 9500km. The wheel had a lot of play, and power consumption went up by about 30-40%. Surprisingly, I couldn’t find a lot of info on the web.

As always, this is not a complete guide, but I try to point out those parts of the procedure that were not straight forward to me. If you’ve done it yourself and have something to contribute, please do so using the comments function.

Tools / Parts needed:

  • Bearings:  SS 6003 2RS   Stainless Steel 17 x 35 x 10 mm
  • Strain Gauge: Mine survived
  • M8 bolts + nuts or similar, as tool (see below)
  • Freewheel removal tool
  • Spoke key
  • Hydraulic press
  • Bearing puller
  • Straight puller

I didn’t do it in the same order as I recommend here, but I think this is the best order to do it.

First step – Take the hub apart:

Remove the Freewheel

Remove the torque blocker (pressed onto the axle, brake side). Mine was just cone-shaped, but the newer ones seem to have a notch, so don’t try to rotate it, use a straight puller to remove it.

IMG_2175

IMG_2187

Remove the spokes on the brake side, this should suffice / I’ve left the drive side spokes in place. Mark the hub, so that you know how to align the halves when reassembling. I’ve used 9 M8 bolts and nuts to actually press on the inner walls of the hub shells. It was surprisingly easy to get it apart by doing so.

IMG_2171

Second Step – Remove the bearings:

The bearing on the brake side covers the strain gauge, which measures torque applied through the pedals. I have read, that this will usually break during disassemble – luckily mine didnt. The bearing came off the axle / stayed in the hub shell. Getting it out of the shell was a job for a hammer + some alloy tubing.

To remove the drive side from the inner part of the motor, we have used a hydraulic press (sorry I somehow missed to take pictures). So this wasn’t easy, and I needed help from someone with the right tools. It eventually came out, and the bearing stayed on the axle.

Removing that bearing is quite difficult, as you don’t have much room below it, to actually use a puller tool. Luckily the mechanic had something like this (with barely enough room to house the cables while pulling):

9082A

 

Third Step – Reassembly:

 

With that bearing out of the way, it was time to clean the axles, place the new bearings onto the shaft. Add new silicone to protect the strain gauge, as well as replacing any heat shrink that has been removed. I then continued with adding the brake / magnetic side, but I’m not sure if it wouldn’t be easier to first push the axle onto the brake side, as there’s no magnetic involved.

Anyway, since I was back at my workshop, I didn’t have the hydraulic press available, and I’ve used my bench vice to gently press the hub halves together (lots of rotating / small steps were involved).

Add spokes, true the wheel go for a ride.

Conclusion:

It’s running smooth again, so it was worth it. It took me about 5 hours to do it, If I’ve had the right tools from the beginning, it would have been much less. So if you want to do this, be sure that you have access to the right tools.

Yet another Lux-RC / Easy2Led bike light

Training off-road during the colder days often also means that it’s getting quite dark. There are lots of bike lights on the market, most of them are either too expensive or not 100% satisfying. There’s however a simple solution using components from Lux-Rc and Easy2Led.

Lux-Rc light engine:

A small board, 3 leds and a boost regulator is already integrated, different configurations are available

Easy2Led light housing:

A good fit for the L33X light engine from Lux-Rc, in addition you’ll need a handlebar mount (Lupine or the Chinese equivalent that can be ordered at Lux-Rc), cables, battery, a momentary switch.

Battery:

Input voltage depends on the light engine, mine is optimized for 2s Li-Ion batteries, I’m not going into detail about building a Li-Ion battery pack. This is dangerous, and you should know what you do, or better leave it. My battery pack has some additional heat-shrink tubing over each individual cell, heat shrink tube over the whole pack, and then a layer of plastidip liquid rubber on top of the heat-shrink tubing. Additionally, I’ve added some foamed rubber on the side that touches the frame when the Pack is mounted to my bike.

Oh yeah, and please use a little less thermal glue, maybe 1/3rd of what I’ve used should be enough.

Balancing the Magicshine MJ-836 Bike Light Battery

There are many reports about unbalanced Li-Ion cells in Magicshine Bike lights. This can lead into overcharged cells, which is dangerous, or at least will damage the cells. The charger which comes with the light does not have any balancing capabilities, the battery itself only has some very limited under/over voltage protection.

To solve this problem, you’ll need to modify the battery (add a balancing connector), and use a different charger, or external balancer. I’ll use my hobby charger, which has an integrated balancer.

This is no complete guide, it needs common sense, and some knowledge about electronics. You should also know, that working with Li-XX cells is dangerous.

If you don’t know how Li-XX balancing works, please read:
http://scriptasylum.com/rc_speed/lipo.html
http://www.rcgroups.com/forums/showthread.php?t=599316
before starting to modify your battery pack.

Adding the balancing connector:

Open up the pack:

The interesting part is the four 18650 cells, remove the top of the pack (shown on the left):

Add a new wire which will end as your balancing connector, this is connected to the “middle” of the pack, the pack is 2S2P.

Your Magicshine Pack should now look like that:

The next Step is to put back the isolation, and bring the balancer wire out of the case. this can be done through the original cable exit:

I’ve added a 2mm banana connector, some heat shrink tube, and a cable tie:

Finished Pack, charging:

test

As you can see, the connections were made as follows:

– from the battery goes to – of the charger, and pin1 of the balancer.
newly made balancing wire goes to pin2 of the charger
+ goes to + of the charger, and pin3 of the balancer.