KU123 100V Mod: success!

CanadianWinters

CanadianWinters

100 W
Joined
Dec 3, 2011
Messages
196
Location
Alberta, Canada
Hi guys,

this is my first controller mod.
A few weeks ago I got a 72v hua tong controller that I wanted to try on my 500W Bafang HT rear setup.

I tried the hua tong and there was no way to make it work with the Bafang, I spent an entire evening checking the phases and hall wires but there was no way to make it work so I concluded that I probably have a broken/faulty hall sensor :cry: .

The KU123 controller can run sensorless and it works perfectly on my setup but the capacitors inside are 63v and the mosfets 70v or 75v (I can't find the datasheet). I still wanted to try a 20S li-mn makita pack on the bike.

Having a spare KU123 controller I decided to do some surgery and take the mosfets and capacitors from the hua thong and implant them into the KU123.

The photos can give you a more clear explanation:

IMG_0513.JPG

IMG_0514.JPG

IMG_0519.JPG

IMG_0520.JPG

IMG_0522.JPG

IMG_0526.JPG

I tried the bike today and it works great. I hit 55kph :)

The next step is to cut one of the shunt to reduce the Amps to 15-20max (now is 30-35 max) so I don't overheat controller and motor.

I love this cheap controller!!

8)
 
was the hua tong broken in some way? what was the benefit in breaking one controller (which already has the spec you needed) to make another do slightly less? are the KU123 programmable?

edit i just read you can run it sensorless but you could have maybe bought the fet cheap and sold a working controller.
 
whereswally606 said:
was the hua tong broken in some way? what was the benefit in breaking one controller (which already has the spec you needed) to make another do slightly less? are the KU123 programmable?
Click to expand...

I believe I have a faulty hall sensor in my motor so the Hua Tong was not working.


The Hua Thong is sensored, it was not working with my setup. The LVC is somewhat around 60-63V. There is no 3 speed switch.


The KU123 is both sensored/sensorless and it runs great with the bafang.The LVC is at 35.75v, and I have the 3 speed switch.

With the KU123 I have more flexibility with my setups, I can run sensored or sensorless, choose the speed if I want to save battery, change between different packs with different voltages/capacity. With the Hua Tong you are very limited.

This was a very simple mod, if I bought the components separately I would have probably spent the same money or more.
I also didn't want to wait!

8)
 
fair enough, i know what its like when you have the kit on hand and you just want to get started. btw modding the hua tongs lvc is not too difficult and there is a pad to ground to get a low speed setting. I feel it would have been less work to mod the hua tong but yes it would never work sensorless so i understand now why you did it.

btw you should try diagnose the hall and fix it dont you get more torque in a sensored setup.

these are cheap though might get one myself and mod it.

I have two hua tong 72v controllers which ill reserve for my high power build. 80 100 mid drive oh yeah!
 
whereswally606 said:
fair enough, i know what its like when you have the kit on hand and you just want to get started. btw modding the hua tongs lvc is not too difficult and there is a pad to ground to get a low speed setting. I feel it would have been less work to mod the hua tong but yes it would never work sensorless so i understand now why you did it.

btw you should try diagnose the hall and fix it dont you get more torque in a sensored setup.

these are cheap though might get one myself and mod it.

I have two hua tong 72v controllers which ill reserve for my high power build. 80 100 mid drive oh yeah!
Click to expand...

Man, It was so frustrating trying all those phases and halls combinations and none of them worked..so I decided to go ahead and do controller surgery :)

I will order the hall sensors for the motor on my next digikey order, I am working on a bicycle computer based on arduino and I still need to decide what components to order for that project.

I was thinking that maybe I can try to take the Hua Tong up to 150V now, I just need to order the fets and caps :). Maybe it's good for my next build too..:)

Do you have a link to you high power build?
 
Here is a video with the performance.


[youtube]adSGuz7nuNc[/youtube]

The motor is a rear bafang 500W 36v 201rpm.
The battery is made with 20s4p Makita-Konion cells.

8)
 
I have to try this on my code 11. 285rpm @ 48v
What is the uf rating on the hua tong caps?
 
Hi bonald,

the big cap on the power side is a 1000uF I don't remember the ratings of the other two on the mosfets side, but as you can see from the photos the're quite big :).

The bike has amazing torque but I try to be gentle with the throttle to not ruin the gears.
 
Every controller really SHOULD offer a way of sensorless operation, seeing the failure rate of hall sensors. Hell if the $13 KU63 can do it.. I like the programmability of Infineon controllers but had to switch one recently for the KU123 too.
 
I have the KU120 controller. 63v caps.
Not really like the one you have. here's a pic of mine.

wHeKMl.jpg

LZlvgl.jpg
 
quick google search shows bmsbattery as supplier, also found page which gives a circuit dia for ku63
http://www.avdweb.nl/solar-bike/electronics/ku63-motor-controller.html

interesting on that page it shows board as refly brand, same as crystalyte used for a while before changing to xiecheng ( I think)
 
those are not IRFB4110 mosfets. you can buy those mosfets on ebay from china cheaper than the time it takes to unsolder them.

usually they are like 20 mosfets for $15 free shipping buy it now. they are not real.
 
bonald said:
I have the KU120 controller. 63v caps.
Not really like the one you have. here's a pic of mine.

wHeKMl.jpg

LZlvgl.jpg
Click to expand...

They look the same. If not they're very similar. Look at the second photo in my first post.

Every controller really SHOULD offer a way of sensorless operation, seeing the failure rate of hall sensors. Hell if the $13 KU63 can do it.. I like the programmability of Infineon controllers but had to switch one recently for the KU123 too.
Click to expand...

I totally agree Miuan!I love the KU controllers for very this reason!

where do you get ku123 controllers from?
Click to expand...

Yes BMSbattery is where I got it :) .

those are not IRFB4110 mosfets. you can buy those mosfets on ebay from china cheaper than the time it takes to unsolder them.

usually they are like 20 mosfets for $15 free shipping buy it now. they are not real.
Click to expand...

Hi dnmun, in the photo you can actually see that they are the chinese "fb4410z", I think they're even worse than the fake chinese irfb4110.

I wanted to do this mod soon. Waiting 3+ weeks for this mosfets from china was not an option, we may get the first snow before they get here LOL.


I hope this simple mod is useful to anyone who wants to go up to 100V sensorless for cheap. I have been looking for it on ES but I didn't find anything.
 
regarding my highpower build, Ive got the parts like the motor, 80 100, a burties linear optical board in place of hall sensors, a frame: a norco savage DH, some acs southpaw freewheels, some planetary gearing (i may for go these and do a belt reduction) a hua tong controller 72v and a shit load of zippy 40c lipo. what i dont have is a decent bracket thinking of copying an ego kit/gng style idea and i also have no time or money at the moment. but when i do build it ill do a thread on here.
 
potatorage said:
How did you get the screws holding the heatsink block to the case off? I stripped the screws but they still won't budge.
Click to expand...

They came off quite easily. You need to have the right screwdriver though, they're really easy to ruin.

Alternatively you can drill the screws.
 
Did you replace 2 64V caps (those on the opposite side of the board from fets) with just one bigger?

Havn't you re-calculate low-voltage part of the board? I thought resistors (3 bigger of them near 2 caps) should be replaced too to reduce voltage of board's low-voltage part.

Could you update this topiс and confirm your controller is still ok?
 
Hi,

the controller is still working perfectly. I am using it on a 9C 2807 motor now. No problems.

Yes I used only one big capacitor because the capacitance was the same of the other two in parallel. I don't recall the values right now.

I only used this controller on a 20S li-mn maximum, so 84v fully charged. I made no other mods and everything seems fine.
 
Impressive. Your successful expirement encourages me to do the same thing. Though I plan to split it into 2 steps:
1. Replace caps and use 16s lipo config (67V charged)
2. Replace fets and use 20s lipo config (84V charged)

And thanks a lot.
 
Yes, I am very pleased with this controller. I love the fact that is sensorless and it doesn't "complain" too much at the start from a dead stop in sensorless mode even with a DD motor.

Let me know how your mod goes :) .
 
I've got some minor updates with my controller. I've replaced all 63V caps with 100V ones and removed one (of two) shunt. Surprisingly, this won't affect bike performance at all! Top speed is the same as well as acceleration.
I still have got no addational battery to check my config with higher voltage, so patience is my second name :wink:
 
16S lipo config is tested and confirmed to do well. The controller withstand such overvoltage with ease.
 
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