Who will be the 1st to run Dual MY1020's?

[Matt Gruber]

Not me!(i have an empty bike path to ride on with a 20 mph speed limit)

But u guys forced to ride in traffic, seems 2 1020's would give enough power at a low price
2x$90=$180 for 2400 watts
even three! for $270 3600 watts!

[xyster]

Can you provide link(s)?

[Matt Gruber]

Can you provide link(s)?

to what? U have to build it yourself. TNC sells the 1020's
Oh...I see.... proof of concept? well, Tim Obrien at powerpackmotors.com has been selling dual motor kits for years

[safe]

I had dreamed of making mine a "Twin 750" a while ago. There are actually even advantages in that you can get more power WITHOUT needing to have more rpms like the overvolting solutions. This means that gear ratios are easier to deal with. The BEST part is that EFFICIENCY GOES UP because you don't have to overamp as much to get the same power...

[Toorbough ULL-Zeveigh]

After having wiped out twice on the hard pack with churned up iceing sugar on top, in the middle of an intersection the week between Christmas & New Years, I'm tempted to go AWD. Either with twin hubs on a Surly Pugsley http://www.surlybikes.com/pugsley.html which can take up to 4 inch tyres or somehow wedge in a crank drive on a Christini AWD. http://christinibicycles.com/bikes-longtravel.php

I thought there were safety hazards to motorizing both wheels without some kind of closed loop feedback to monitor wheelslip or some such. That there is a danger of losing control under particular conditions of steering input. Any truth to that? Also would 29ers make good AWD candidates? Primarily intended for use on snow & ice.[/i]

[safe]

I thought there were safety hazards to motorizing both wheels without some kind of closed loop feedback to monitor wheelslip or some such.

I was thinking of a "Twin" motor configuration so that the motors were physically connected before the chain going to the rear wheel. The advantage is that you can find motors that run at lower rpms and that makes gearing easier.

But the idea of "Twin" Hub motors is good too.

Any time you can get the "Efficiency Peak" and the "Power Peak" to be the same (which means a pretty low current limit on the controller) then that "spreads the joy" of improved efficiency across the entire powerband.

It's better to have two hub motors running at half the amps than one hub motor that is overamped. It's just overall BETTER.... (there is NEVER a case when overamping bets oversizing... oversizing always wins)

But the added weight might be annoying... however, if you got two small, light weight and high efficiency hub motors that might be really good... (it would even improve the weight issues that people have with these 5304's that weigh in at 25 lbs)

[fechter]

With two brushed motors, you could have a series/parallel switch on the motors. Series for low speed/high torque and parallel for high speed.

One disadvantage of dual motors is the core and friction losses from both motors will always be present unless you have some kind of freewheel clutch between them that allows only one motor to turn under low load conditions.

If a single motor takes 2 amps to run at no load, then two motors would take 4 amps (even if you only feed power to one). The no-load current is essentially all wasted power.

[Matt Gruber]

for 30-60 mph that's 30-100 amps.
a 2 amp loss is a bargain!
.
i wonder if a car AC clutch could disengage #2? i don't see why not, except it may draw as much power to ENGAGE. could be an advantage in racing where an amp could make u win.

[safe]

I'll post this chart again. Two 20 amp motors are better than one 40 amp motor.

The bottom line is that efficiency "trumps" friction by far. When you are dealing with motors that have only a few amps as their no load speed the losses due to overamping dwarf everything else.

And you don't need all this "fancy" stuff either.

Just run two smaller and lighter hub motors at low current limits... it's ALWAYS better than one hub that throws away energy with nothing to show for it.

Study the chart... it's true for all motors that are presently overamped.

High voltage and low amps on both would be best...

[xyster]

Because the x5's are too heavy for serious off-road use, but I love their torque, I'm planning as my second bike a dual AWD with twin brushless hubmotors. Two 8lb Puma's each connected to it's own 72v40a controller, both controllers connected to a single throttle and a 90v lithium manganese battery pack. Should be 7,200 watts that way. Pretty good for 16 lbs of motors. Second choice would be dual 408s or 4011s.

[Matt Gruber]

safe
so why did u decide against dual 1020's?

[safe]

safe
so why did u decide against dual 1020's?

I haven't necessarily decided against them. For my old bike (the one I already have) I'm going to just keep it as it is with no more modifications. For my two new ones planned this spring (the moment the garage stays warm enough to make working there enjoyable) I plan to have the motor as a "bolt on" item. So I might have a multitude of motors that I'll experiment with and maybe even a Twin someday. So I'm leaving my options open.

You can get the same "effect" as Twin 1020's if you use a PMG 132, but then you pay $800. Even the Transmagnetics motor would be nice. So I'll be trying a lot of stuff depending on how things work out.

Right now I have a 750 Watt MY1020E3 and a 1200 Watt MY1020 to start with for each bike...

[Mathurin]

[offtopic]

After having wiped out twice on the hard pack with churned up iceing sugar on top[...]

Try running about 4/5th the pressure in your front tire.
Or, try studding your front tire.

All bikes always have the danger of loosing control under particular conditions of steering input, that's not specific to winter. All the wheel slip monitoring needed is built into the rider. At least with front motor + legs on the rear.

And yeah, I've been eyeballing the Pugsley for a while, too...
http://www.loyno.edu/~sphickey/stable/pugsley/


Other options:

Turner bikes


http://forums.mtbr.com/showthread.php?t=174333


Moots, light & expensive

Note that the rims have holes drilled into them.
http://forums.mtbr.com/showthread.php?t=180382

Sexy drilled snowcat rim:


[/offtopic]

[xyster]

Wow! Great looking off-road bikes. Which means they're almost certainly way out of my price range

[fechter]

Why does the Moots have a gear cluster on the front wheel? 2WD?
I like the coffee thermos on the front fork...

[Mathurin]

That Moots Snoots is built for the Iditasport, it's a human-powered winter journey tracing Alaska's Iditarod Trail. It's a 1840km race/survival challenge event, support is limited to boxes of food and clothing sent to checkpoints prior to the start. Being self-reliant is critical, and it's the reason for things like the front gear cluster. The thermos, forks and downtube are designed to carry fuel on this bike. I suppose you could use them to carry coffee, though. But I like that the Moots weighs next to nothing, being made of titanium. For myself, a cro-mo Pugsley is more realistic.

[Toorbough ULL-Zeveigh]

I thought there were safety hazards to motorizing both wheels without some kind of closed loop feedback to monitor wheelslip or some such.

I was thinking of a "Twin" motor configuration so that the motors were physically connected before the chain going to the rear wheel. The advantage is that you can find motors that run at lower rpms and that makes gearing easier.

But the idea of "Twin" Hub motors is good too.

Any time you can get the "Efficiency Peak" and the "Power Peak" to be the same (which means a pretty low current limit on the controller) then that "spreads the joy" of improved efficiency across the entire powerband.

It's better to have two hub motors running at half the amps than one hub motor that is overamped. It's just overall BETTER.... (there is NEVER a case when overamping bets oversizing... oversizing always wins)

But the added weight might be annoying... however, if you got two small, light weight and high efficiency hub motors that might be really good... (it would even improve the weight issues that people have with these 5304's that weigh in at 25 lbs)

My apologies. It's because of where my mind's been at recently that I jumped to the conclusion that this was an AWD thread.

Rather than go back & delete my previous posting, I'll just attach this & live with the shame & humiliation of my mistake.

[BiGH]

lol i think its a spacing thing? maybe they only could get rear rims that thick with the rear hub installed?

either way that would be a cool bike to econvert with dual motors using slick baloon tyres!