Long range Qulbix 75

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Motormark   10 mW

10 mW
Posts: 27
Joined: Jun 23 2016 2:03am

Long range Qulbix 75

Post by Motormark » Dec 20 2017 12:49pm

I’m starting a new build.
I’m an amputee, Right leg, and my girlfriend is a fanatic ATB rider and in the weekends she go on trips for trips from 40km -80km (25/50mls), mostly singletrack.
A few weeks ago a friend lend me his Bultaco elektric ATB (2Kw motor, 50V/26ah 1,3KwH) to ride along with her.
The Bultaco Brinco
The battery lasted only 35km (22mls) It Is impossible to buy a lager battery for the Bultaco, and i started looking for other options.

Battery had to last for 80Km single track. Bultaco did 35km with 1,3kwh, so it must be 3kwh.
Motor power 2kw
Light if possible
Compact, because we have to transport a normal ATB en My MTB ebike in a Citroen Berlingo.
Durable, fail proof. Since i have only one leg, and cannot walk if the bike fails.
Budget 

After several weeks searching on the internet, i decided to build my own.

With the info i found here on the forum here i went for:
Qulbix frame.
Build my own Battery 72V/44,8 Ah 3,2KwH
Kelly controller KBS72121X
Cycle Analyst V3
A donor ATB bike fort he parts
A Crown or cromotorV3 (for reasons of finance, the first motor wil ba a Crystalyte Gmotor thati have from a preveus project.

The people at Qulbix told me that i needed a 140 wide frame to fit this large battery, but my calculations told me that i can do with an 75 small frame, and i want the controller inside the frame.

At this point i received almost all the parts i need, en started building.
First the design of the battery. It’s not easy to cramp a 3,3Kwh battery +controller inside a Qulbix 75 frame.
Battery design
IMG_20171214_124538_2_resized_20171220_063005548.jpg (234.51 KiB) Viewed 635 times
Next is to finish the battery and mount it together wit the controller.
To be continued…..
Tips from you, experienced builders are always welcome.

felix991   1 mW

1 mW
Posts: 19
Joined: Sep 26 2017 6:48am
Location: DFW, Texas, USA

Re: Long range Qulbix 75

Post by felix991 » Jan 01 2018 10:07am

I think you mean Qulbix 76r frame. I too just finished one of these and I love it. I was going to build a pack like yours but at the last minute I found the 16Ah lipo packs on Battery King and bought those instead. I am running 4 in series to give me 68v at 16Ah and on a Edge 1500W hub motor I am getting about 30 miles on a charge and a top speed way faster than I want to go. 50+

Since I just finished mine I have not had a chance to add a build thread on here yet but will here in the next week or so. You should also start a build thread on your bike. If you are going to buid your own battery pack there is another member here selling a car battery operated spot welder for batter tabs that is way better than any of the battery tab welders you can get on aliexpress or ebay.

Search the threads for JP Spot welder. I have one on order. They are about 165.00. I too will eventually build a pack like yours but the lipo route was fast and easy. They were on sale for 83.00 each a few months ago but have now went to 99.00 but watt to watt they are cheaper than the 18650 but a little more pain in the ass to charge. I plan on buiding a custom BMS to charge the lipo and if that does not work out then I will go back to the 18650. My last bike which I still have has the 18650 in a 52V 20A steup and I have rode that bike over 1800 miles.

The Qulbix is a lot heavier bike and I went from 19Wh to 37Wh in this new fram with moto rims and tires. The ride and stability of the new frame is off the chart compared to the converted MTB frame but I did not expect to loose so much power and to be honest that is using the power sparingly. If I ride hard on it, that jumps to about 55Wh per mile.

I was going to use the 3000W Mxus and I am glad I did not. The 1500W Edge has plenty of power and speed and I could not imagine a larger motor at this point. I am running the 1500W at almost 2800W but it never gets hot. I also incorporated a 3-way switch for Hi-med-lo power which equates to 50%, 75% and 110% (yes you can over drive those) but to be honest I spend most of my riding in 50% mode to save power and other than the super fast take offs and wheelies I really dont miss the power and the top speed is still 30mph.

This was my first all out build and I am interested in seeing yours completed as well. Start a build thread...

Motormark   10 mW

10 mW
Posts: 27
Joined: Jun 23 2016 2:03am

Trial and error 1

Post by Motormark » Jan 06 2018 5:56am

Trial and error.

Because of the battery is so big, and uses 96% of the frame's space, I need to build the battery first.
After a few attempts with a professional welder machine we figured out that the machine have a "stick securety" and cut the current at schortcuts.
Last edited by Motormark on Jan 06 2018 6:19am, edited 1 time in total.

Motormark   10 mW

10 mW
Posts: 27
Joined: Jun 23 2016 2:03am

Trial and error 2

Post by Motormark » Jan 06 2018 6:10am

Now used al professional spotwelder fron the automobile industry.
We attached a external footswitch and wires from the electrodes to our homemade handheld spotwelder.
This time we started with minumum current and minimun time setting. With little succes.
As we increased the current and time, we started to have some hopefull results, but at the point where we realy began to see good spotwelds, the major fuse in the workshop blow every time.
Up to plan C.....

Motormark   10 mW

10 mW
Posts: 27
Joined: Jun 23 2016 2:03am

Re: Long range Qulbix 75

Post by Motormark » Jan 18 2018 2:05pm

160 Amp is to much for this BMS

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