How many watts can you safely feed a 9c?

El_Steak

El_Steak

10 kW
Joined
Aug 11, 2009
Messages
638
Location
Gatineau, Quebec
Just ordered a big kahuna 100v / 100a controller from Methods. Got all the bells and whistles like regen, 3-speed throttle and cruise control. Way overkill, but it's going to be the last controller I'll need in a long time ;)

I'm now looking at the different possibilities for my battery setup. I want headways but I'm not sure how big I can go with my nine continent, 2806 rear motor.

I'm considering 72v (20 cells) in a 26inch wheel or maybe 86v (24 cells) in a 20inch wheel.

At 30-40 amps, both setups are fairly efficient (>80%) at my target speed of 55-60km/h. I think that the 20inch wheel setup would really haul asss, but I'm a concerned about heat issues, phase wires shorting, etc.

Any thoughts?
 
Smaller wheels are alot less stress on the motor. You should ask methods about the 9c he is runnning them again!
 
Arlo1 said:
Smaller wheels are alot less stress on the motor.
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Yeah, the 20 inch wheel sounds like the way to go for fun and efficiency. Just have to deal with pedal clearance issues.


Arlo1 said:
You should ask methods about the 9c he is runnning them again!
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Didn't he just blow up his third X5 on Friday? :shock:
 
Yeh something like that. I run my x5 just as hard but I have a x5304 in a 20 inch wheel. So it spins faster and cools better and has more gear reduction due to the size so the amps that are needed to get the same acceleration are alot less!
 
I run my front 20" wheel 9C motor in the back of a BMX ( no chain ) at 48v 50 amps, not much for hills around here but i pull 1000w constant and 2000w + when accelerating, Methods runs his at 100v 100 amps but after a few hard launches they get too hot to handle..

Safely, 50 amps is no problem imo. voltage depends on wheel size and winding type.
 
torker said:
Dr bass did a hillclimb ride with his wife and toasted a 9c Not sure what v/a he was running. Have to search for that thread.http://endless-sphere.com/forums/viewtopic.php?f=3&t=12369 I think this is it.
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Yep, I saw that one last night. It's the thread that got me worried ;)

He was running 2 x 15ah ping packs in parallel at 48 volts (54v). He was using a 50 amp controller.

I think that the problem was that the climb was so steep that he wasn't able to go much faster than 10-15 km/h. At those speeds, the motor is extremely inefficient (30-40%). I guess the remaining 60-70% becomes excess heat.

The same motor in a 20 inch wheel would have allowed him to go faster, bringing the motor in a more efficient bracket and providing additional air cooling from the higher speed.
 
Ypedal said:
I run my front 20" wheel 9C motor in the back of a BMX ( no chain ) at 48v 50 amps
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Is that with your brand spanking new 48v10ah Headway pack? :D

Do you have the 2807 (9x7) or 2806 (10x6) in your 20 inch wheel?

What's your top speed with that setup?
 
I'm sure a 20" wheel would have helped alot . YPedal You say not much for hills around here but how does it do when climbing? Also what spped do you get with 48V 50A and 20" ? Is that a 2806 or ? I ask because I want to do a rear motor setup for backroads/some hills.
 
Cool video.. I guess that must be the 2806 So does it seem to pull up hills ok? Do you have any offroad vids of that setup.?
 
Nice video. It looks scarier when you watch it like that than when you are actually riding the bike.

I'm surprised to see you can get up 50km/h with a 2806 in a 20 inch wheel. I get the same top speed when I use this motor in a 26" wheel @48volts / 35 amps

Maybe you have 16 cells in your pack? (The ping pack I used only has 15s)
 
If you want to take a look at my thread here: http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=13447 I am using a 9c in 20" wheel on my recumbent. I am running 14s limn (51v) with a controller that limits me to about 68a, with peaks of 84a. When accelerating, I can give it wot and it will pull 68a up to about 39mph, and above that the current starts dropping, and rests at 30-34a when cruising at 43-44mph.
 
The rest of the question is for how long. Dr Bass found out how long.
 
Thanks for all the comments on the 9c motor. I use a Crystalyte 404/408 two speed front hub motor in a front 20 inch wheel at 72 volts with a 35 amp controller. I can operate at 35 mph on level grades. I have been able to operate at over 2200 watts without any problem so far. I failed my previous 20 amp controller on hills. I am interested in a motor that has better performance on hills. The Crystalyte 500 series motor is too heavy for my application.
Don Gerhardt
 
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