controller for running Q100H at 48 volts, and motor maintenance

[quuxman]

I've been quite happy using my Q100H (front wheel motor) for the last few years with the controller it came with from bmsbattery.com (S06S), but now I'd like to change the controller to run on 48V. I want a new controller for 3 reasons: first I'd like to get a better battery and have it work on both my bikes, secondly my existing controller overheats after about 1k feet of climbing while the motor isn't even warm, so I'd like a higher amperage controller. And third, a small speed and power boost for the Q100H would be a nice bonus. Ideally I want a controller rated for around 20 amps that I can limit to 15-17 amps (by modifying the shunt?) to eliminate my overheating problem entirely.

Is anybody using a Q100H at 48 volts without any issues? I was going to order a KU93 from bmsbattery.com but I found this thread about the new controllers shutting off at higher throttle:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=58720

The controllers from e-crazyman were also suggested, and this may be a decent option (though no PAS input):
https://www.ebay.ca/itm/48V-600W-brushless-controller-for-E-bike-scooter/300352534034

I also have a question on Q100H maintenance. I've ridden it 2500 miles and over the last 500 or so, it has gotten noticeably louder (maybe 50% more, though still very quiet compared to my MAC setup) along with an increase in vibration. Is it worth disassembling it? I can't figure out how to get the case off. I have a gear puller but I want to be sure how to proceed before I start forcing things.

 

[docw009]

If you are using a KT LCD display, you could try another KT controller. Like this one for 25A.

https://www.ebay.com/itm/Electric-Brushless-Controller-For-Ebike-KT-9-Mosfet-Sine-Wave-36V-48V-25A-500W/223494790537?hash=item340953dd89:g:QYkAAOSwmkBcE3~R

I believe the covers on the Q100H's screw in into the motor.

 

[motomech]

.... my existing controller overheats after about 1k feet of climbing while the motor isn't even warm, so I'd like a higher amperage controller.

I doubt your controller is overheating (too hot to hold in your hand?), because my experiences w/ Q100 C's and H's is the first thing that really overheats are the phase wire connectors (I know that because they melted), then the phase wires themselves. I agree the motor stays cool, especially when it's on the frt.
Be still, you don't want any more than 20 Amps on a 48V system, what you want is a large controller case to shed the heat, like a 9 FET job. This is the controller I've been using w/ my Q100's for years;

https://www.ebay.com/itm/48V-350W-9MOSFET-ebike-Electric-Bicycle-Brushless-Motor-Controller-with-LED/223971278277?hash=item3425ba7dc5:m:mgxcwDHTuIgK4sxrLPhfyrQ&var=522736001534
It's not a sine wave and it's only a 3-speed PAS, but on a low speed "assist" bike, 3 speeds are enough and there is no big gaps. I've used the sine waves before, but like you said, they are wimpy and the more one rides, the less needed is all the data. I actually prefer the sealth-y LED unit. It's a 17 Amp controller, but shunt modd'ing it will bring it up to 19 - 20 Amps. Try it stock first. More watts are better, up to a point, as it helps keep the bike moving faster up the hill for longer, keeping in a more efficent rpm range. I don't know what kind of forks you have, but this controller will be stronger than the KT, so sure your torque arm(s) are solid. I use one on each side just to be sure.

Is anybody using a Q100H at 48 volts without any issues?

Yeah, a 36V pack is a waist of space. Actually, the last couple of years, I run the Low geared "201" on 52 Volts for a decent top speed and it climbs like crazy (for a mini). It's my fav. combo.

The noise and the roughness is no doubt one of the whl. bearings, probably on the right side. You can know, if it gets louder when the bike is leaning to turn. I had a right side bearing go bad, so I took it out and showed it to a bearing, belt and chain supply and they matched it up.
Yes the side cover screws off (lefty loosey). The rears are a bear because the free whel. gear tightens it. They require a special wrench be made. The frt.s are usually not so bad and there are a couple of "dirt floor" tricks that can work.
If you want to try it, let me know and we can go over them.

 

[quuxman]

I believe the covers on the Q100H's screw in into the motor.

How do you twist off the cover? I tried putting longer bolts into the three screw holes to torque against, but the bolts just bent and the cover didn't budge at all.

I'm pretty sure it's the controller overheating. It gets too hot to touch, like hot enough to fry an egg. It doesn't turn off entirely, it seems to switch to walk mode where it ignores the throttle, looses all power, and chugs along at a few mph. Pretty weird behavior for overheating, but that's what it does.

I'm using the SLCD1 display, which is nice for the speedometer and odometer but I really wish it reported watt hours
https://bmsbattery.com/home/548-16155-s-lcd1-e-bike-lcd-meter-ebike-kit.html#/196-voltage-24v_36v

Forgot to mention I have the 201 speed version of the Q100H

Thanks for the link motomech, that looks like a reasonable option, probably without any modification at all. I wouldn't want to go over 17A anyway.

The 25A one docw009 linked would be way too powerful and would require modification. I'd be too worried about melting my motor or its cables.

 

[docw009]

How do you twist off the cover? I believe BMSbattery sent someone a tool. It's long bar of steel that screws into three of the screw holes you were talking about.

I've got a Q128 with a fried speed sensor. I didn't even try to open it. I just put on an external sensor.