# Controller and battery power test



## V96400A (Mar 13, 2011)

I have an electric motorcycle that I DIY'd in 2010 with the following: 
ADC k91-4003, Kelly KDZ120v400a, 31 TSLYP40AHA, kilovac contactor, mini BMS
and I want to test the output power of the Kelly. The issue is, I don't yet have an ammeter and am not concerned with specific power output. What I want to do is (using parts I already have, because I am not yet ready to buy an ammeter) connect an extra contactor that would remain off until I approach the speed at which the motorcycle stop accelerating (which is 60-65 up ~8% grade through a windy {not curvy, blowing} canyon). I would have two switches on the handle bars to switch off the contactor that provides battery current to the controller and immediately switch on the contactor that would provide battery current directly to the motor. The real issue I think I have is the difference in voltage that the controller supplies at the switching time vs the amount of battery pack voltage that would be suddenly engaged. I once put full pack voltage, 99.2 volts through a contactor to the motor (because I am crazy like that) and I shattered the sprocket on the motor shaft. I have video of this on my youtube channel (noleanderthegreat). 
So I am trying to wend my way through finding what approximate voltage I would be at under full load using the controller because I wouldn't want to just go try it out without doing all the theoretical scenarios (I'm not crazy like that), because of the potential of losing control of the rear-end at 60+mph. 
I have an understanding of the way the controller works to a point. I am not clear on how fast the transistors are switching per a given motor speed, but I am pretty sure that the transistors are never T-on, constant to allow non-PWM'd battery current. I will also be measuring voltage at the motor when I am under the target load and if there's too much of a difference, I won't be actually testing this out; I know a guy who will though. 
Anybody have any comments or concerns about my idea or even measured the output current of one of the Kelly controllers? I have read on forums that the claims are false and I won't buy another Kelly product, because I am done supporting China (I mean it!). I am aiming for a Soliton Jr some sweet, sweet day. Until then, I need to get up this pass without grandma in her Prius honking at me, expecting a motorcyclist on a bike that looks like it should be fast to be going...fast. zai jian


----------



## Qer (May 7, 2008)

Pardon my french but that idea is moronic and has been beaten to death several times in this forum.

If top speed is achieved because the controller is fully on and there's nothing more that the pack can give you'll just be adding weight (and open up for total fuck ups).

If top speed is achieved because the controller goes into temp derating (not unlikely considering the brand you've selected) just as little as 10 Volts would cause a current kick that could potentially weld the contactor shut and give you a torque enough to make the rear tire spin wildly which, in that case, means you might end up having to choose between:


Releasing the cluth, which means you will regain the control of the MC at the cost of sitting on top of an electric motor that will start to disassemble yourself between your legs.
Not releasing the clutch and "ride it out" with a spinning and smoking rear tire.
So, you're ready to expire your life already or do you want to hang on to it a wee bit longer?


----------



## drgrieve (Apr 14, 2011)

I haven't heard of any performance reports on thunder sky 40ah. I don;t think they could put out 10C or 400 amps without sagging very badly.

Perhaps 6C @ 20% voltage sag. But this is a WAG. 

That would give you 31*40*3.3*6 / 1.2 = 20 kW to the motor. Which would be ~16 kW motor output. That should be plenty for a bike to move? I have no idea about bikes I must say.

Perhaps look at other factors - loose connections - limit settings on controller - temp derating - is the controller or motor getting hot? Not sure if your controller can monitor motor temp? Also check your throttle is sending full acceleration signal.

Of heard of other folks have the above issues when not getting performance expected. Of course you might have a faulty controller?


----------



## V96400A (Mar 13, 2011)

I am going to ignore the first guy's response, he didn't even read my post and speaks like an moron. Thanks for the response drgrieve. I have checked controller settings for temperature, current, motor speed, power profile and throttle input. I originally suspected that I had the throttle set to 3 wire, when I have a hall effect, but actually changing that setting made no difference (I tried to gain a better understanding of what would happen). The motor and controller barely feel warm and I have a huge heat sink on the controller. 

I am thinking that the controller just isn't putting out enough power to get me through the steep, windy pass. I am also trying to get a sense of a logical upgrade to get the power I need. I am not sure whether I should increase the voltage to 120 (the motor shouldn't mind because I won't over speed it, so it won't over volt and spark excessively) or get a controller with higher amp rating, but not another kelly. What I have learned in all this is that you should always overestimate your power and needs (especially if you don't know the math to calc-it -out), even though I thought I overestimated my power requirements, under this one instance, I don't have the power. 
Under every other circumstance, the bike is peppy, passes traffic easily in the city and my gps/speedo tells me my top speed is at least 78 mph on the level with no wind and fully inflated tires. 
My batteries are still new enough to add some extra cells to get the extra voltage, but I don't know if I should do that and get the controller upgrade.


----------



## palmer_md (Jul 22, 2011)

V96400A said:


> I have read on forums that the claims are false and I won't buy another Kelly product, because I am done supporting China (I mean it!). *I am aiming for a Soliton Jr some sweet, sweet day.*





Qer (aka first guy) said:


> Pardon my french but that idea is moronic and has been beaten to death several times in this forum.





V96400A said:


> I am going to ignore the first guy's response, he didn't even read my post and speaks like an moron.


This is too much...haha.


----------



## EVfun (Mar 14, 2010)

Why don't you measure the voltage on the motor at the speed where you stop accelerating? If it is very close to the pack voltage at that point then the controller isn't limiting your performance. It is just on 100%, doing the same thing a bypass contactor would do. In that case you would need more voltage to make the motor draw more amps at that rpm.

Bypass contactors are exceedingly dangerous. They have the nasty habit of welding themselves on when you try to open them. It takes a very small voltage difference to draw hundreds of amps because a series motor basically looks like a short circuit with a back voltage. They are kinda like a giant zener diode, where the zener voltage varies with rpm and load.


----------



## V96400A (Mar 13, 2011)

I have read about that potential for the contactor to weld shut and I am happy to hear some good responses. I have tested full battery pack current to the contactor and that one time I did it, the contacts did not appear to have suffered. When I tried using the contactor to directly control the motor, I was aware of the potential and I took precautions to make it as safe as I could and I was not on the vehicle. 
I understand that it doesn't seem like the most wise thing to do, but those members who wish to speak down on people should consider how many of us never knew an electric vehicle existed just a short time ago (2008 for me). I am an orphan with no family, nor do I have friends who are EV experts to run my ideas by and these forums are the only place I have to go for quick information (I have read obsessively about EVs since 2009). I hate most of the EV community, because so many of the elders act like everyone should know (or search through thousands of forums to find) that contactors are not meant to switch high power. Those of you who are aware of the newbies and assist with information, I really am thankful and wish you the best.


----------

