12p3phPMDC wrote:Gary G? Gary, how many kw are you putting through your Nexus3 setup?
There is a guy in SD named Dave, who has a bike shop in Pacific Beach called Rusty Spokes. He's the one who builds custom choppers using Eteks and Mars motors, running off 36V/50Ah SLAs. All of them use standard Nexus 3 hubs. Not sure how much power he is putting through these, but I'm guessing 5-10kW, in any case.
When I wsa running my Cyclone 1000W setup, it hit peaks of about 2650W, but that is at the battery. I'm currently working on this bike (a 20" Dahon Mariner...) right now. Initially, I'm using the same Cyclone 1000W motor and the 55A controller, but with different gearing. Instead of going through the crank, the motor now drives a jackshaft with a #25 chain drive as a 1st reduction. There is a 24T sprocket on the motor shaft and an 80T sprocket attached to a White Industries ENO freewheel, on the jackshaft. The output of the jackshaft is an 18T track cog which drives a 36T sprocket on the Nexus-3 hub. The crank now has a single 44T chainring, on the standard Cyclone freewheel setup. It drives a 22T sprocket which is also on the Nexus-3 hub. The big reason for doing a dual chain to the rear setup is so I can "reclaim" use of the pedals. It still requires a freewheel on the crank, but now it doesn't have to be an expensive ENO, as it is not carrying the main load anymore.
Doing dual cogs/sprockets on the Nexus hub required a lot of trial and error, and head-scratching, but I finally have a workable solution. What I did was used a Dimension "Big Cheese" 110 BCD adapter plate and then drilled 4 holes to add a 22T 64BCD "granny gear" chainring. Sandwiched in between these is a 16T Nexus cog. I also had to use about a 2" hole saw to open up the hole in the adapter plate, in order fo it to fit over the front portion of the Nexus hub, right behind where the cog slides onto. With this arangement, the 22T sproket is on the outside, and the sprocket the jackshaft drives is on the inside. I'm using a standard Sugino 36T 110 BCD singlespeed chainring, but there are lots of choices here. I have a 53T, but I've seen even larger ones around.
After I get a baseline of the performance with the Cyclone setup, the first thing I will do is replace the controller with one of methods modified 18-FET Infineon controllers, and up the current to about 80A. I'm initially using a 16s5p a123 pack, but I may also try upping the voltage by adding another 8s5p pack. With an 80A limit. the power should go up close to 4kW, and with a 24s/80A configuration, closer to 5.5-6kW. With an 80V setup, I'll change the 18T cog on the jackshaft to a 12T.
After I've killed the Cyclone (gotta stop hanging around with the testosterone kids...
), I will pull out the Cyclone, and install my 3210-10T (kV of 135, vs about 70 for the Cyclone...). With the 16s5p pack alone, I'll change to a 14T motor sprocket,, driving the 80T and go up to a 40T sprocket on the back, driven by the 18T cog. Going up to 24s will again require dropping down to a 12T cog on the jackshaft.
Finally, when the sensored 3220-7Ts are ready (hopefully in the next couple weeks...), I will put this in place of the 3210, and open up the current on the controller to 100A+, and really see if I can start breaking things.
If the Nexus-3 can survive that, I think it can handle most anything. Methods is going to set his 3220 up with a Alfine 8-speed hub, which has a disc brake, and also is supposedly very strong, compared to the other hubs, like the Nexus-3/8. His setup will also put even more power through, as he will use a 24s LiPo setup so about 10 more volts and who knows how many amps.
Once I get the jackshaft mounted, and the basic setup complete, I will take some pics and start a new thread.