Fully, converted (finished today).

[bbushwacker]

Hey everyone,

I have been browsing this forum lots and was happy to find advice on real-life issues.

Mine were completely homemade, and I was told that I was compensating subconsciously not having a motorbike (which is a wild speculation without evidence).
I had to have a solid fully (own a fast non-e commuter) as multipurpose for BC trails/commuting etc. and the budget was limited -- thanks to Gord and bikerescue, I bought an affordable specialised SX frame (04) with springs. It had to be this frame, seriously.

Trouble began, as pure DH the frame came with no rim-brakes. I did not want to go with single brake (off-road+trails, weight!). No big deal, ebikes have this front-disc ezee. This is a bomber jr fork, 20mm through. Adapters from 12-20mm are fairly easy to machine (found a workshop) and the crucial torque-limiter was supposed to go through the fork dropout.

Reality check with ebikes. Axle is too short, will allow only 5mm on each side for washers/nuts. Thought that was nuts and considered giving it a try, but fortunately they seem to have just the right stuff around, so I got a rear ezee, with disc and flywheel (fits in perfectly) kinda-prototype from them. (Heaps of thanks!)

Assembly was straightforward, discs were made to fit and it rolls! Now I need to solve where to put the battery (48V/NiCd 8Ah, pretty darn heavy~10kg). Thought about the top beam of the frame or, below held in place by two under-frame bottle-holder screws and some straps. Any suggestions, there?

Anyways, big thanks to ebike, Justin and his awesome team and bikerescue (Gord's team). The entire process took five weeks and it appears to have worked out! The knobby tires produce quite some drag, but with some pedaling biking in Broadway traffic was a breeze.

Cheers everyone and thanks for the stuff on the forum.

 

[AussieJester]

Nice looking bike congrats I would place the battery as low down as possible, front tube would be the spot i would go for if there is enough clearance.

Best of luck

Kim

 

[bbushwacker]

- this is what I was hoping, too. Clearance is (for my experience) insane, so that should work. Has anyone tried to attach batteries to the frame by the drink-bottle holders? Would only be the positioning that goes over the threads, as straps should prevent it from dropping, holding the weight. I try to avoid duct tape for its BAUHAUS-aesthetics.

Thanks, this forum really works!

 

[docnjoj]

As usual, Aussie is right! U can use velcro or alloy straps and even woods strips cemented with good adhesive to attach sidecovers to. It has all been done here! weight central and reasonably low, with some minor exceptions ! Read the center of gravity thread! Some real racers give suggestions!
otherDoc

 

[dogman dan]

On these full suspension bikes, I have often thought, putting a few of the batteries on the top tube, and a few on a rear rack would be a good compromise. keep the rear rack under 5 k and it's doubtfull that it would be that much of a bother. Very nice, It's exacty what I've been wanting. My next build is starting Wednesday when my motor arrives.

 

[bbushwacker]

Thanks for the posts. I just noticed today that apparently the NiCd's are improving with every cycle. The first ride was more like. Ah. That is what everyone is talking about, then.

Today on the fifth charge, I started to have fun, rather than seeing it as a functional, somewhat useful tool.
Throttle is not digital any more, there is more than get on, 100%-bzzzz-0%, get off.
I had to let go of the throttle for some surprisingly good moments.
This is cruising! I am about to send Justin an email...

Still need to install the batteries...
Will keep you posted, however, the hurray-molecules that some e-gland in my brain produces signal >whatever, let's go for a ride<

(The fun centre in my brain, however started to wonder what happens at 72V. (Question: Is there something like volt envy? Yes, there is a Y-chromosome involved.))

 

[Link]

(Question: Is there something like volt envy? Yes, there is a Y-chromosome involved.))

More like kW/kWh envy, but you've got the basic idea.

 

[docnjoj]

Nicads would rule if they were a little more energy dense and a lot less toxic! I luv em!
otherDoc

 

[bbushwacker]

Battery mounting on the frame is not trivial with rear suspension bikes as the rear racks are fixed to the seat post only.
Fixing this really took much longer than it should have. I was carrying the 48v8Ahr battery in my backpack, while researching for options.
I found an seat post rack that claimed to hold 12kg and tied the battery in one of those trunk bags on the rack. Several issues emerged, one, the bag was heavily insulated, easy, the padding had to go; the centre of gravity was high and far at the rear end, which had an unpleasant impact on the bikes' handling on trails; small drops and stairs mean a lot of stress for the butt joint and I was suspecting that I was outside operating limits for the rack.
When I bought the rack, I had checked the inverted angle, just as an option, but now I have just flipped the entire assembly. The battery now rests on the frame, held in place by the straps on the rack. Handling improved dramatically and I am not afraid of snapping the rack on trails. As it is a downhill frame with a very much relaxed, laid back seating position, the width of the battery is not really interfering with the small amount of pedaling on hills.

Next installation was Justin's 6V DC/DC converter. Plugs between battery and controller, done in two minutes and so worth the money! My old dual bike lights that used a clunky NiCd (dead) had a new purpose and were mounted with one of the sturdy U-lock holders right on the fork. The halogen lamp is very bright, but not-so-useful for night riding on trails, as it moves with the handle bar. Helmet mounted would be the way to go. But for commuting, I feel much safer with the lurking you-know-this-guy-is-going-to-come-out-right-in-front-of-you-car, as they don't any more.

A CA was finally installed, when my budget had recovered. These should come with every bike! I see now, what and when I burn most of the batteries capacity.

Here is a question: I have limited the controller to 17Amp max (because the one of previous controllers' MOSFETs was fried, after four 25Amp fuses blew over the last two months with the 48V setup, and this was not the first one according to Justin) and 39V low. Now I get randomly anywhere from 5Ahr to 6.5Ahr before the output drops to under 200W. Final voltages come back up to 46.5-48.0V after 5 minutes recovery without discharge. I should get well over 7Ahrs out of a 8Ahr battery, shouldn't I? Are these settings too conservative?

48V/8Ahr NiCd battery, Ezee controller and motor on a heavy bike (estimated 30kg); range 15-20km with minimal assist (me-bike) and between 17.2 to 20.7 Whrs/km consumed. Max speed on the flat: 34km/hr at 750W.
Justin offers Crystalyte controllers that would allow to go up to 25Amps for this setup (limited for the battery). Does anyone have experience with the change in torque, that would be the result?

Thanks for any input and cheers!
Bjoern

 

[AussieJester]

Really like how you mounted the battery very clever use of 'standard' rack, just mounted backwards :: wink ::
Whole setup looks good, some more pics wouldnt hurt though Maybe a vid or two if you can also
of the bike in action...nice job anywayz mate congrats looks pro

KiM

 

[bbushwacker]

Here are two more pics. Please note that you can chose the angle when buying seat post racks for some manufacturers. This was a no-frills axiom. Rack&bag $75, but I removed additional side bags.

 

[AussieJester]

Surprised someone hasnt thought of this before reversing a standard rack i mean... (apologies if they have) I havent seen it ... ingenious for those with limited tools/know who dont have the means to fabricate cutom mounting system, DEFINITELY more attractive than the usual method seen here ie. Duct tape and more Duct tape :-S

KiM

 

[dogman dan]

Look at the same rear rack and see something nobody else did. I love it! That's the difference between seeing and merely looking, as most do.

 

[Ypedal]

Nice bike !!! i'm building something for a local guy very similar to this with a rear eZee.. i hope the disk brake lines up properly.... gulp..

Mounting heavy packs to the downtube of these frames is a frickin challenge when you have limited tools and experience with this stuff.. but it can be done if you want it bad enough !

That bar looks a tad close to the privates..

Using the water bottle mounts is not enough for the weight of the pack, but it can be used to bolt a block and prevent the pack from spinning side to side or down..

see:
http://www.ypedal.com/Chaos2.htm

 

[Mark_A_W]

I notice the Shimano Deore shifters - they look like 9 speed to me.


So, what cluster is fitted? And does it play nicely with the 9 speed shifters?


Very nice build - I like it. Careful of your nuts though...

 

[bbushwacker]

Ypedal, you are so right about the battery position on the down tube. That was the first place I have been testing (...and trying to wiggle holders in place, etc.) but finally I did not have enough confidence in the threads of the bottle holder, even if tied up. You appear to have that solved well with the chaos2, although I did not recognize a stop/block that would prevent the battery from engaging in downward movements, are the straps holding it tight enough?

Fiddling the caliper over the disk brake was a bit of an issue, but just took some swearing, time, and the right combination of spacer washers. The eZee's rear geometry is in fact good-natured.

Mark, the freewheel is a standard 7-something. I did not care so much, as anything more than one gear would have been accepted. I am no sprocket-maniac and this became less important with the ebike (can actually not really sort the 27 speeds of my commuter me-bike). Yes, the shifter is a 9 speed. I am using 9, 7 (one up) and 5 (two up) without any adjustment. The XT derailleur, when well lubricated seems to comply.

Hehe, was worried about that clearance, too. Normal operations are totally fine as the bike sinks in as soon as there is weight on the shocks. When I have to get off, either controlled or fast, I rather move to the rear. Thought about those padded moto-cross seats, but I guess a half a meter of thick heating pipe insulation would do without being optically offensive.

Thanks for those comments!

If anyone has suggestions for the CA settings mentioned above, I would like to hear them, too!

Cheers!
Bjoern