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| https://endless-sphere.com/forums/viewtopic.php?f=28&t=65549 |
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| http://www.astroflight.com/
Mid
Mount Motor Mod
I
think I have finally found the best way to have a stump pulling gear
for my MtGoat CycleTruck; use a direct drive hubmotor with the mid
mounted Cyclone mid-drive motor with a single speed gear reduction
ratio behind the seat post on a rear extension. This will use the hub
motor as the high gear. Then torque will slowly shift to the mid
mount motor. Yet still use power from both motors.
That
way I will not have to use a absurdly slow gear ratio to climb the
steep hills. But I will need to figure out exactly the right
gear-ratio to use from the mid-mount motor mod. If your hills are
steeper than an average geared hubmotor can deal with a mid-drive
motor can be geared down lower than any geared hubmotor. A 3000watt
cyclone motor is just barely strong enough to climb our 16% grades
with 400lbs total combined weight. So you could use the larger
cyclone motor. But without the higher gears to cruise with, a DD hub
will help better than using the human powered drive chain and
sprockets.
To
find the right gear ratio I would need to start with a 42t sprocket
cassette because it is almost too slow with a 40t chainring on the
crank using my 17inch tire [my front wheel is even smaller; 20”].
Justin says the direct drive hub motor should be running at the same
time for hill climbing so the mid motor so it won't fight the core
losses from the hub motor. The low geared mid-motor should have a
little more power than the hub motor at the steepest part of the
climb; because the hub motor is very inefficient when climbing the
hills.
It
maybe good to mount the direct drive hub motor in my [16” rim]
front wheel. But I may also need a larger battery pack because I will
be climbing the steep hills faster. I don't know how much extra power
will be needed by the extra controller etc.
You
need two controllers. So
learn to build them:
DC-Motor-Controller-for-Electric-Bicycle These two lectures tell all about how to use two motors for better hill climbing. The full version of the lecture is here: “A guide to multi-motor (2WD and 3WD) ebike drive system" |
Two hub motors; one geared
Two motors; one mid-drive:
2WD
Yuba Mundo V4
(Build Thread)
Two
stage reduction (for single hill climbing gear):
2" diameter pulley ÷ 12.5” rim pulley (on the drive wheel)= 6.25:1
ratio x 7:1 ratio (primary reduction) = 43.75:1 ratio = close to 12
mph
 |
This
thread tells a lot about how
to rig two motors to one bike:
|
Dual motor
“You
can do this with One battery pack, One throttle, One 3-Way &
Cruise & EBrake using Two controllers paralleled, Two motors
individually tied to each controller, and Two CAs - one for
each.
The overall power is divided somewhat arbitrarily
between the two controllers depending on load.
-
Going
uphill, both will pull evenly.
-
On
somewhat of a flat whilst in Cruise Control, one will take the lead
and the other will go into "slip mode"; pull enough
current so that it essentially freewheels... however on the
slightest increase in load - it will pick up the slack until Cruise
cannot be held.
I
don't measure Amps; I measure pack Voltage because the shunts have
been modified by trace-beefing and I do not have equipment capable of
measuring scant ohms accurately, so I just measure voltage. I know
the battery capacity, I know from experience how to set the amount of
theoretical current to the wheels, and thus am able to calculate
roughly the overall power consumption. The CAs validate this by using
Miles per charge; I know how many miles I should have covered by
x-amount of voltage drop - which is not exactly linear, but then I
understand that too.”
The overall power is divided somewhat arbitrarily between the two controllers depending on load.
Going
uphill, both will pull evenly.
On
somewhat of a flat whilst in Cruise Control, one will take the lead
and the other will go into "slip mode"; pull enough
current so that it essentially freewheels... however on the
slightest increase in load - it will pick up the slack until Cruise
cannot be held.
From
this thread:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=29833
two-speed-gearboxes
Mid-drives / Zero Trail Steering / Variable Speed Crank / Tilting trike technology
/ how to motorize a big vehicle/ Hub Motors / How much power do you really need?
/ how to motorize a big vehicle/ Hub Motors / How much power do you really need?
Thanks for sharing this blog,such a nice information.
ReplyDeletewww.siemens-abb-motor.com