All out Power! 100V Gurus! Talk to me about up-grades!

[LI-ghtcycle]

Ok, I am about to join the "dark side"!! :lol:

I'm wanting to see what is possible with a pretty basic mid-drive design and a little shade-tree mechanicing!

I want to make my first foray into the world of ridiculously fast E-Biking!

Here are my main concerns:

1) How to find the limits of a motor and NOT melt it!

2) How beefy do I need to make my Phase & Battery wires to keep things sound at 100V 30A?

3) How much money should I expect to budget for these kinds of up-grades?

I'm wanting to make this my first truly high-end high-power project, all silicone wire, I'm guessing I will need to use 10G starting at the exit of the motor, from the battery and to the controller for phase & battery connections?

I'm also wondering what the best way to manage heat, being an in-runner I don't know if I can ventilate like I could with a out-runner hub motor, and I know that I could make some rudimentary cooling fins of aluminum on the case, however, I'm not against an elaborate active cooling method, I'm thinking some form of water misting might be ideal?

And this motor:

http://www.goldenmotor.com/

(The one to the far right, the 800W)

Spec sheet:

http://www.goldenmotor.com/hubmotors/BLT-800W Performance Curve.jpg

From the listed specs, I am already seeing that this motor is designed to run between 24 - 60V nominal, and being such a large heavy motor, I am hoping it has a pretty good copper fill, but I have no idea about this kind of thing, and I know this isn't a well known motor, but I'm curious to get everyone's input.

Here is what I know:

The motor is listed by the manufacturer as a motor that will run at 1160 RPM's at 48V (on the spec sheet it's actually about 41V) however, at no-load, it will spin at 2800 RPM's.

I have backwards calculated the Kv's and it's a 28.4 KV motor if you go with the "working rpm's" as listed with 1160 @ 41V according to the spec sheet's efficiency rating (correct me if there is a better explanation on that spec sheet, I'm still learning about this) so my thoughts are to slowly work my way up to 100V and see what happens.

My major advantages with how the motor & controller are mounted on the bike now are that I can at a moments notice put my hand down to check the motor & controller to make sure they aren't getting too hot.

I will be building a purpose build frame with the help of my neighbor in most likely 20 inch BMX style steel with extended wheel base for the final prototype to take to the local race track, but I am hoping I can test the various voltages on my current bike and push the limits enough to know if 100V would be too much, or if say 84V or something else in between would better?

Thanks!

 

[wesnewell]

1) The motor has a watt rating. That's a continuous use rating. Most will probably do 50% more continuous. And 500% more for short periods (3-10 minutes).
2) The battery wires are constant current. Phase wires aren't. So the battery wires need to be larger. I ran close to 30A through 24awg without melting the copper. Anything larger than the battery wires from the controller will be safe. 12awg minimum. The larger the better in terms of voltage drop. The phase wires goes to the motor windings so should be at minimum no smaller than that. Again, make them larger than the the wires coming from the motor and you will be safe. The larger the better in terms of voltage drop.
3) I have no idea. I paid $33 for the controller I use at 100V 40A. All depends on how much battery you buy. That's going to be the major cost.

 

[dogman dan]

The first thing you do, is get a thermometer wire into the can. Feels ok, don't cut it. You need to know how much the heat is spiking inside.

Double the rated wattage sounds like a real good rule of thumb to me too. Start at 72v 20 amps, and work your way up from there.

I think flames will shoot out those motors pretty quick, at 100v 40 amps. They do fo hubmotors, why should those similarly rated motors be any different? But 72v 30 amps sounds like you could get away with it for shorter rides.

 

[nechaus]

To me, these motors are a Little to slow the rpm is only 1100 with some type of load for the stock voltage...
Golden motors are pretty crappy...

 

[LI-ghtcycle]

Yeah, you're probably right there D-man, I might need to see about up-grading to a beefier motor for consistent 100V performance.

Maybe the 5Kw motor here:

High Power BLDC Motors -- Amazing Performance beyond your imagination!
Model: HPM5000B -- High Power BLDC Motor
Voltage:24V/36V/48V/72V
Rated Power:3KW-7.5KW
Efficeincy: 88%
Speed: 2000-6000rpm (customizable)
Weight:11Kgs
Casing: Aluminium
Length (height): 126mm
Diameter: 206mm
Shaft: customizable
Features: Compact design,Water resistent, Stainless Steel Shaft, Self Cooling Fan
Applications: Electric car, electric motorcycle, electric tricycle, electric golf carts, fork lift, electric boat, etc.
Drawing(.pdf) 3D View

Buy Now
$446

I bet this one would handle 100V 30A just fine! 8)

I know it's too wimpy for LFP, but I'm not trying to go 90+ MPH just about 50 or so.

 

[LI-ghtcycle]

To me, these motors are a Little to slow the rpm is only 1100 with some type of load for the stock voltage...
Golden motors are pretty crappy...

Well, some people say the same thing about 9C motors, but they work just fine for many of us, even at high voltages properly ventilated and used for short bursts of high speed (maybe not 100V, but 74V pretty commonly).

I'm not looking to try and make any records, just make a splash in the Portland E-Bike community.

 

[nechaus]

That motor is MUCH better, it will bring grins and well worth the extra hundreds ..
if you have about 500 dollars you can really look around and see what you can get best for your buck

 

[Hillhater]

Reading some of the "high power" build threads, i suspect you will have to do some serious thinking (and $$'s) on a suitable controller. ...unless you are happy to just spend big on a Sevcon etc ??

 

[liveforphysics]

Buy the new motor Hal and Accountant are offering. It's $500 or something, and it's everything you could EVER want a hubmotor for a bicycle to be. Makes the second biggest hubs look like a toy.

 

[gensem]

Its 400 or 450 euros for the hub motor. But you should not buy it. There are not many, and I still need 1 or 2 more.

 

[LI-ghtcycle]

Buy the new motor Hal and Accountant are offering. It's $500 or something, and it's everything you could EVER want a hubmotor for a bicycle to be. Makes the second biggest hubs look like a toy.

Frock motor!?

I wana mid-drive!

I am intrigued, is that something in the for sale section? Colossus?