Kelly controller - lost power with full throttle

I just got a Kelly KEB72601X controller. What I'm experiencing is when I full throttle for a couple seconds, the power completely drops out as if I've hit some limit, but then afterwards if I wait a second or so, I can throttle back up again (it's not my battery bms). If I don't full throttle, I can ride around fine.

I've played with the phase/battery max settings from very low to very high, as well as the lower voltage cutoff, put that super low, and still experience the issue, so I'm guessing it's related to something else? Not sure how to troubleshoot this.

anyone have experience with this?

Does it also do this when the wheel is in the air?

I'm guessing you need to change the deadzone of the throttle in the kelly programm. try going from 80 to 100.

Is it setting an LED fault code?

Thanks for the tip eee291, I changed the "Brake sensor ending point" that was set at 80% to 100%. It still is shutting down, but, it feels like it is happening later than it was before, so not as crappy of a ride.

It doesn't do this in the air, just when riding.

Tommycat, no the controller is displaying green LED.

I experimented a little, on a straightaway when I'm at about 20mph, I WOD and it shuts down after about 3 seconds. So then I got up to about 20mph again and only WOD for 2sec, then back to ~50% throttle, then back to WOD, and keep doing that, and it lets me continue to get more speed. It's just when I leave it WOD for more than 3 sec it shuts down.

I also shuts down quicker, depending on how fast I'm going, for example from a dead stop, if I WOD, it will shut down much quicker.

Not sure if that helps with the diagnosis, but that's where I'm at.

The best thing to do here would be to take screen shots of the programming values you are using and post them up.

How many peak amps is the motor pulling on launch?

brumbrum said:

The best thing to do here would be to take screen shots of the programming values you are using and post them up.

How many peak amps is the motor pulling on launch?

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^^^^^ +1
Sure sounds like a current problem...working with no motor load. Motor can take 80 amps max- 56 nominal, controller-60 amps max output. What can your battery continuously sustain ?

But on over amp draw doesn't the controller just back off a little to acceptable values? Sounds like your losing it all....? Could you maintain WOT continuously after power loss, thru stopping and checking the LEDs for a fault code...

If it is one of the newer Sine Wave controllers... (which I have experimented with a few of) they all cut out under hard acceleration, which absolutely sucks. In communication with Fany from Kelly she basically admitted that this issue was inherent to the cheap Sine Wave controllers they make (and obviously hadn't got it sorted before releasing them). The older square wave type are so much better IMO - and I've never had one cut out under full throttle (unless at LVC). Unfortunately you may have a lemon.

So fun times, I experimented a bit more with the numbers and eventually the battery crapped out, wouldn’t recharge. I took it apart and discovered some nickel strip burnt out, losing the connectivity with some of the cells. I fixed it up, but while I was there i noticed the cells are Samsung 18650 29E, which have a continuous discharge of 2.75amps, peak of 4.8. It’s a 20s7p, so the seller bullshitted me saying it could handle 50amp continuous and 150 peak. In any case, seems like I’m trying to pull way too much current out of this battery. I’m gonna dial the settings way back and see how that goes.

I was waiting on a cycle analyst for this new controller so wasn’t able to see the numbers, I just received it today, so I should have better info in the future.

I’m also finishing up a custom battery build 20s7p with Samsung 25R cells, which should be able to discharge much more current, plenty more than what my current battery. I’ll be curious to see how that one plays out.

Also as mentioned, good idea, I’m gonna WOT and after it shuts off, will check the controller LED to see if it’s showing an error.

If the nickel strip actually burned out, it probably isn't even nickel. Dunno what it would have to be to burn out under whatever current passed thru it, but I've seen some very high currents on some very thin wires and they didn't burn out, even enclosed inside things. :/

After fixing up the battery, as mentioned it was working again, but then pooped out again. I took a closer look at my motor phase connections and realized they were melted together. They are 45 amp APPoles so no surprise there, I’m pulling around somewhere around 60amps. I’m ordering some 8mm bullet connectors, but in the mean time switched them to XT90s, long story short, everything seems to be working fine now for the most part. It’s only tripped off once on me when accelerating from a stop, but otherwise it’s working well. So seems like my shitty connection was the culprit, or, something related to that.

NeedForSpeed said:

I took a closer look at my motor phase connections and realized they were melted together. They are 45 amp APPoles so no surprise there,

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Actually, it's probably not the current rating of the connector, it's probably either the crimping of contact to wire, or it's too large a wire (insulation thickness, usually) preventing the wire from being able to easily move in the housing, so that the contacts can float and self-align.

If the contacts can't float and self-align, then they don't mate flat with the other contact, and resistance is very high.

If the wire is too stiff or tied in place close to the connectors, or is bent in a way that pries the contacts at angles to each other, it'll also prevent alignment.


That's the disadvantage to the powerpole design, and has turned out to be the cause of many of the melted PPs I've seen. (bad crimps is another main one)

Another cause, related to the above, is non-genuine PPs, which often have weaker springs that don't force alignment of contacts nearly as well as originals do. Their housing plastic is also often softer, so ti deforms easier even before it gets hot from the current thru the high-resistance connection.

The larger PPs, PP75 or SB50, etc., have stronger springs, harder contact casings, etc., so it's less of an issue than with PP45s.

I’m pulling around somewhere around 60amps.

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FWIW, the battery amps have nothing to do with the phase amps (which can be much higher).