mounting a hub-motor, torque-arm, .. man thats hard work

[kraeuterbutter]

hmm..
Variante 1 ist zu teuer
Variante 2: da feil ich wohl 2 Wochen dran rum, oder ?
kenn mich mit Metallen nicht so aus..
ich habs mehr mit Balsaholz
und aufgrund meiner langjährigen Balasa-Holz-Erfahrung kann ich sagen: so eine Drehmoment-Platte würde aus Balsaholz nicht halten

 

[Tiberius]

Na, ganz einfach.
Eines 4-jahriges Madchen kann es tun. (Wenn man die Maschine schon habt.)

2:
Fuer Bafang Motor, der Schlitz ist 10 x 12 mm. Bohrst du 10 mm Loch. Woche 1: Feilst 1 mm bei eine Seite. Woche 2: Feilst 1 mm bei andere Seite.

Oder 3, die Balsaholz Variante:
Nimst du die Platte aus Balsaholz, drueckst es in Sand. Und darin den geschmolzen Stahl giesst.

Entschuldigen bitte, mein Deutsch ist nicht so gut.

Nick

 

[kraeuterbutter]

hm...
i have some plumb here from sylvesterßs "plumb - casting"

maybe i can use the balsaholz and the sand to make a plate from plumb


however:
we have managed to make some technical drawings so far

besides: your German is very good, for sure lot better than my English

 

[Tiberius]

Langloch = Schlitz? Meines billiges Woerterbuch hat es nicht.

Nur die Breite vom Motorachse Langloch ist kritische*. Der anderer Loch etwas Spiel haben kann.

*To make a test mount for my Bafang motor I used a 10 mm end mill. "End mill" or "Slot drill" will not be in my dictionary either.

Nick

 

[kraeuterbutter]

"Langloch":
"Loch" = hole
"lang" = long

so a "langloch" is not a perfect circle, but a half circle, two straight lines, and a half circle

for dictionary:
mabye the best (online) one:
LEO Deutsch-Englisches Wörterbuch

(and if there is something not explained, they have a forum were a lot of native speakers (in both directions) can help you)

leo.org says:
end mill = Fingerfräser, Schaftfräser
hmm.. even in German i don´t know what that is

oh, for "Langloch" leo.org says:
slot [tech.]
elongated hole [aviat.] [tech.]
long hole [tech.]
long slot [tech.]
oblong hole [aviat.] [tech.]
slot hole [tech.]
slotted hole [engin.]

 

[Tiberius]

leo.org says:
end mill = Fingerfräser, Schaftfräser
hmm.. even in German i don´t know what that is

Sounds right. The German manual for the Maximat says Fräsarbeiten for Milling.

Here are slot drill and end mills
Chronos Ltd Milling Cutters

Nick

 

[kraeuterbutter]

so.. some progress with my bike..

new brakes, new brake and gear-cables, new gearchanger, ...



i also grinded the fork so much, that the axel of the motor could now be inserted completle and the washer fits:

so: also i have grinded the fork, you can see: the torque washer does not work like it should..
i would have to grind another 4mm away so it work
but than the fork would be realy weakend, so i don´t wana do that..
-> friend will make the torque plate

 

[kraeuterbutter]

here a pic how i wided my fork:

lying on my back,
two feets in one strap, the two hands hold the other strap and than pulling!!
girlfriend inserts the wheel

and here a picture that shows, why my girlfriend is a little bit angry with me:

our bedroom - a bike-workshop in the moment

so:
here now, how far iam in the moment:

i have only mounted one big apple so far, because i didn´t knew if it would also fit at the rear-fork..
it does, so another one was ordered

i did a - powerless - testride with the bike, and:
the Schalbe Big Apple definitly is worth the money !!
in some situations its smoother to ride than my other mountainbike with front-suspension-fork !!
so the ads were not promissing too much

in the moment iam wondering: should i mount the controller in the saddle-bag or in the black box as on the picture...
what do you think ?

 

[flecc]

The black box keeps the cables short so maximises the current transfer efficiency as long as the cables from the battery are thick enough.

You'll need to take your girlfriend and straps out riding with you in case you have to change an inner tube.
.

 

[Tiberius]

It would be better to put the controller near the motor rather than near the battery.

Battery to controller: 2 wires, steady current.

Controller to motor : 3 + 5 wires. Switching at high frequency.

Nick

 

[kraeuterbutter]

hi flecc..
yes, this was also what i was thinking..
(specially because iam conditioned by rc-modellflying with currents of 100-200A and there always trying to keep wires as short as possible)

i used the tool from Gerd Giese
HERE:
http://www.elektromodellflug.de/Uploads/Ltg_bg_V1.xls

its German, but you only need to fill in 4 cells:
line 2: the length of the wire (only one wire counts, you don´t need to double)
line 3: the cross section of the wire in mm²
line 4: the innerrestistance of the connector (see list:    Elektromodellflug - Hochstromstecker )
line 5: you don´t need to change this
line 6: part of the result
line 7: the max. current that can happen (e.g. 20A for an ebike)
line 8: the RESULT: the amount of volts that are lost through the wire

so:
when i mount the box in the saddle-bag i have about 120cm more wire-length than mounting it like on the foto in front..

so: 1,2m wirelength means:
with 1mm² wire and 15A current: 0.66Volt lost
with 1,5mm² wire and 15A current: 0.44Volt lost
with 2,5mm² wire and 15A current: 0.27Volt lost

so: on a hilly section with my 33Volt and 15A max. current
i will see another 0.66Volt loose when i mount the controller in the saddle-bag
so about 2% less power compared to mounting in front

on normal driving in flat area with less current (7A):
with 1mm² wire and 7A current: 0.31Volt lost
with 1,5mm² wire and 7A current: 0.21Volt lost
with 2,5mm² wire and 7A current: 0.13Volt lost

so about 1% less power compared to mounting in front
or: instead of 231Watt it would be 229Watt

----------------

i see with this:
wirelength seems to be much much less critically than in our rc-modells (with often low voltage, e.g. 10Volt and high currents, e.g. 200A)

so it even appears to me, that 1mm² would be enough and looses are far less than 1Volt

----------------

so the mainreason for mounting would be: were does it look best

is this correct so far ?
or do i have a big mistake in my thoughts ?

 

[kraeuterbutter]

@Tiberius:
thats funny..
i always thought that too (keep wires between motor-controller as short as possible)

but - at least for rc-components - its other way true..

"keep all wires as short as possible" -> thats always true..
but: if you have no other choice, than its better to make the wires between motor and controller longer instead of making the wires between controller and battery longer..

reason: when the wires between controller and battery are too long, and the inner resistance of the battery is maybe also high (not inline-soldered cells for example) than it can destroy the controller..

iam not sure how and if you can transforme this rules also to the e-bike components..
and if it is (life)critical for the controller when the wires from the battery become too long (it would be 70cm in my example instead of 10cm for the controller<-> battery wires)

 

[john]

The current from controller to motor is generally greater than the current from battery to controller, so more losses would be expected there.

I believe the reason for keeping the battery wires short is that too much inductance on this side can blow the MOSFET's in the controller .

 

[kraeuterbutter]

hmm.. that with the currents is another thing i have noticed other way round at controllers from rC-hobby..
just when looking at the wire-diameter:

for example:

this controller from Kontronik is the half size of my bike-controller
but it can handle 63Volt, 120A continous and 200A for 15 seconds
it also costs 10times as much

nevertheless you can see: battery-wires have more diameter than the cables going to the motor

or here another controller (25Volt, 80A/100A) in my electric helicopter:
picture: http://www.kraeuterbutter.at/Bilder2/AcrobatSE/Umbau Orbit 20-12/Motor_eingebaut_DSCF1460.jpg
4mm² cables from the battery, 2,5mm² cables to the motor

 

[kraeuterbutter]

so..
also its not difficult enough, iam nevertheless tending to mount the controller under the seat int he little sattle-bag, also it means longer wires (at 36V and that low currents should not of that big problem)

to make it EVEN worse:
i was looking on my bike, the steel frame
-> i want to wire it INSIDE the frame !

what do you think ?

the outer diameter of the two thin horizontal tubes is only 14mm
so i guess: about 12mm inside

it would be hard to get the cables inside there..


my idea:
i make two holes..
then i put the bike 90° upside (frontwheel is located over the rearwheel)
with a thread and a little weight on it, i let the thread go throught he tube
and put the little weight out at the other hole on the downside

then i can pull some more threads through it

on the threads i fix a single wire.. and now i can pull this single wire through into the tube and out at the other hole

what do you think ?
10 wires through a 12mm inner-diameter tube with the holes not on the ends of the tube but on the sides ?!??

 

[john]

to make it EVEN worse:
i was looking on my bike, the steel frame
-> i want to wire it INSIDE the frame !

what do you think ?

I think it is possible, but tricky. But you already have some cables outside the frame, is another cable or two going to be an issue?

 

[kraeuterbutter]

well.. its not one or two...

in fact it would be
23 cables !!

yes, some are combined by silicon-rubber,
but nevertheless..

 

[Tiberius]

That will be a lot of work.
There is also the danger of cutting the insulation on the wires on on the sharp edges of the holes.

Nick

 

[kraeuterbutter]

yes, cutting wires..
a problem i was also thinking about..

hmm.. maybe i can defuse the problem with my dremel and a grinder

but another - well - problem has occured:
the seat-post
when i want to remove the seat, i have to pull it out ~30cm
so the cables need to be 30cm longer as realy needed

 

[john]

but another - well - problem has occured:
the seat-post
when i want to remove the seat, i have to pull it out ~30cm
so the cables need to be 30cm longer as realy needed

I had my controller mounted at various places on the frame. Currently it is just in front of the carrier, on the two mounting posts that run from the carrier to the down-tube (but you don't seem to have these on yours).

I would have a slight worry about overheating with the controller in a bag, mine is in an aluminium box.