5000W Goldenmotor build

ebiker

10 mW
Joined
Mar 9, 2009
Messages
21
Location
Nuremburg, GERMANY
After reading this forum for months and collecting ideas over ideas I want to present my first build now.

Everything started when I first bought my 1000W 48V Goldenmotor kit from ebay. I took my old Mountainbike and tried to fit the parts to the frame. As battery I bought a 10Ah 48V lifepo4 battery from ebay. The problem was that is was too big to fit into the triangle of my frame. So I had to think of another solution for mounting the battery. As I definitevly didn't want to mount a rack to my bike, the only space to fit the battery was on thr top tube of the frame.

elektrofahrrad_01.jpg
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To make a first test ride and to protect the battery from any kind of water I decided to wrap the frame triangle into some plastic sheets.
elektrofahrrad_04.jpg

First test runs showed a top speed of about 54 km/h. Which felt pretty good, but not as good as I wanted it to be :mrgreen:
Moreover the look of the bike was still pretty worse. So the next step was to build a new canopy around the frame.

I disassembled the frame and cut some aluminum u-profiles which were fitted to the frame triangle. Then the sides were covered with 1mm aluminum sheets.
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After painting and assembling the bike looked like this:
elektrofahrrad_05.jpg
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elektrofahrrad_07.jpg

As I was still not satisfied with the power, I decided to take it to the next level. I bought a 72V 70A Infineon controller from keywin and some lipos from hobbycity. So with that setup pumping about 5000 W into the motor the next test ride showed about 63 km/h top speed and an impressive torque.

[youtube]mXlLhE1VtGA[/youtube]

But this is definitevly not the end of the story. I will completely redo the frame (probably a different frame), install large disc brakes and maybe some time later try to get one of Methods 100A controllers (if he will sell them as complete units, not kits again :mrgreen: )
 
Nice build! It looks very complete and the frame work looks great!

I am actually in the process of building up a goldenmotor bike using the methods controller. Ill be sure to post some performance data:D
 
Hi ebiker,
You have a nice e-bike in Germany. What speed can you go up a 10 % grade? Do you have a method to measure volts and amps? I currently use a 404/408 two speed hub motor at 72 volts with a 35 amp controller in a 20 inch front wheel in my Safety E-Trike. I need better performance going up hills.
My family is originally from Marburg.
Don Gerhardt
 
Im glad someone is following my lead in pushing GM to its limits.

Im going to say a few things that you GM guys should pay attention to..

PLEASE DO AIR COOLING. WITH HOLES BIGGER THAN MY HOLES ON MY BUILD
PLEASE INSTALL A TEMP PROBE.
PLEASE REPLACE PHASE STOCK PHASE WIRES FROM THE AXEL TO THE CONTROLLER.

This motor has a tight axel. I barely got the temp prob in mine. Im not sure if it can accept larger wires. The next best alternative is to leave the stock phase wires in the axel and keep them short as possible and replace the rest of the harness.

You are dumping more power than I will ever touch. I already run 24s 88v @ 45A is plenty for me. I may go to 60A but in no way the GM can take 5000w constant especially in the stock sealed up configuration. On a 4 mile trip around the block at 40-45mph WOT my motor did reach 160-170F. But this was with air cooling and 30F air temps. The motor was probably 30-40 degrees higher after my ride when the bike was not moving air through the motor to cool it. At this point after my ride I could smell the varnish from the windings. The motor runs fine with short bursts but cant take it constant. With the air cooling mod i found that the area between 25-35 mph is the most efficent speed for this bike. 35 mph on my build at 88v. On your build at 72v it would be around 27-28mph. It will use about 800-1200w in this speed range. It can shed the heat in the range pretty well. Even with agressive bouts of acceleration as long as you stay in that range you will be cool. Once you go faster than that over 60% of the energy you dump into the motor would be wasted as heat which is bad. The motor doesnt have the mass to take that type of heat for extended periods like the X5 can. Since you got a controller from keywin you need to sit down and figure out how to program and set up the controller like on my build. My switches keep me legal at 20mph. The switches can select a mode where i can stay in that sweet butter zone with goods speed in the high 20s and low 30s. If you wanna be agressive you can choose the 100-120% modes for the high speed fun. Do this to save and protect your motor. I hate to see someone "FAIL" when I already did it for them.
 
@ gerhardt
What speed can you go up a 10 % grade?
I don't have a 10% grade here, so I can't tell you. Sorry.

@icecube57
On a 4 mile trip around the block at 40-45mph WOT my motor did reach 160-170F.
On my testride (about 7 or 8 miles) the motor was still touchable. And I did mostly acceleration runs. But to replace the phase wires with larger ones is a good idea.
But right now I disassemled that bike. I bought a new, larger frame to fit a large battery box in the triangle. And I think I'm going to replace the motor with a Puma in a 20" wheel for better torque. Let's see if the Puma can take 5000W :mrgreen:
 
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