Final Checks of my Work

[the_horak]

Hey All. I've been manually installing a KT 30A controller into my bike that came with a proprietary controller originally. I'm done and now I wanna make sure that I am all good.

I had to test and try to figure out how the controller connects to the bike's hall sensors and I think I'm good. No strange noises, smooth acceleration and I'm breaking 30 mph. Is it possible, though, that my hall sensors are not wired correctly? I only ask because I don't know this stuff well and my technician experience has taught me that 'just because something's working, it doesn't mean it doesn't have an issue'. Do I know I'm good because the bike runs?

Throttle only - With my old controller, I would be recording a top speed of around 32-33 mph on a full charge. Now the bike is having trouble breaking 30-31. I've got two 52v batteries powering the 48v controller, just like with the old one. Is it possible that the KT needs some more software tweaking? Or is this just how it is? I know there are differences in registered speed and I wish I did gps testing before I removed the old controller (I do know it was definitely accurate 'enough'). Old controller was 28A/14A.

Last question: I ride throttle only a lot. Any settings I should make sure to enable to ensure that I am getting peak throttle performance at all times?

I know this is long and these questions likely seem stupid, so thank you all.

 

[bengxe]

I don't have any experience with KT specifically, but have you measured the amp draw of the new and old controllers? 28 and 30 are close enough that your 28a controller may have been drawing more than your 30a KT. Does the sticker on your KT not say 30A +-2A? Your old controller probably said something similar. That's what this sounds like to me. It could also be a speed limiter, but you're going past 28mph. It's possible the KT is looking for a higher full throttle voltage signal than your throttle is sending, and that might be a programmable setting. Or like you said, a speedometer calibration difference. Hall sensor problems would show in other ways, like starting from a stop.

 

[the_horak]

28 and 30 are close enough that your 28a controller may have been drawing more than your 30a KT. Does the sticker on your KT not say 30A +-2A? Your old controller probably said something similar. That's what this sounds like to me.

Good point. I never measured current out of the old one. I can measure current out of the new one though. I've got a meter with a current ring at work. The old one didn't have a ± on the label but a tolerance seems reasonable.

It's possible the KT is looking for a higher full throttle voltage signal than your throttle is sending, and that might be a programmable setting. Or like you said, a speedometer calibration difference. Hall sensor problems would show in other ways, like starting from a stop.

Good to know about the hall sensor. I'll get a voltage reading off the throttle to check that.

 

[the_horak]

So I should be good with the motor's hall sensors right?

 

[slaphappygamer]

The difference in speed could be as simple as having the wrong tire size input in the display. Someone recommended to me to have your tire properly inflated. Then mark the tire contact to the ground and roll the bike until that mark contacts the ground again and measure the distance between the 2 marks on the ground. A 27.5 tire could measure at 28.2”. This could effect the speed readout.

Also be sure that your C5 setting is set to 10, to get maximum current, if your battery can sustain it. If the start is too harsh, you can also try settings 00-02. These values will change the way power is ramped and will smooth the start of power delivery while keeping maximum current.

If your hall sensors were an issue, you would hear strange noises from the motor or the motor will try to spin backwards.

Were you perhaps riding into a headwind when speed testing? Or maybe you had a tailwind at the time? And did you Speedtest on the same place?

Having your P4 setting to 0 and C4 set to 03 will ensure you have full power on throttle at any PAS level and from a dead stop.