£300 budget for kit improvement

[KirstinS]

£300 budget for kit improvements

Right – this time I actually have £300 in my mucky paws so I want to canvass opinion before I hit Buy at bms battery

1) What I actually really need is a new 36 volt battery (mine is really on its last legs)
2) What I’d like is a bit more torque
3) Maybe also a little more top end speed - not crucial but I don’t want less

I currently have a 8fun 250w front motor, Ku65 controller (which they no longer seem to sell as it was) and 36v bottle battery (9ah old style). I do sometimes overvolt to 48v and get c23mph. I’d like to retain this option

My thoughts are to get

1) A 36v new style bottle battery http://www.bmsbattery.com/36v/683-bottle-ebike-battery.html
2) A q100H motor (201rpm) http://www.bmsbattery.com/ebike-kits/632-250w350w-q-85100sx-motor-e-bike-kit.html
3) A new/spare controller ? I think this is what they now call the type 1 ku63/65 http://www.bmsbattery.com/controller/692-hall-sensorsensorless-250watts-brushless-hub-motor-controller.html
4) A couple of spare thumb throttles and some torque arms whilst I’m there – totals about 20 bucks

That lots comes to 297 USD plus I’m guessing another 200 USD in shipping (I cannot actually tell for sure as BMS say they have to ship by TNT but don’t included this in the shipping options at checkout)

That’s about 300quid

Given the requirements and budgets – is there a better/cheaper/alternative way ?

 

[Deleted member 4366]

Your present motor might be more powerful than a Q100H. I think it would go quite well with one of those 48v batteries with the included 20A sine wave controllers. Maybe put a couple of crimps in the shunt, which is accessible, to get the current down to 17 or 18A. You can always solder it to get it back afterwards. They come with the other stuff too, so it would be easy to swap. Torque arms as well.

 

[KirstinS]

thanks d8veh but my 8fun is sensorless only motor (3 pins) - this wont play nicely with that will it ?

Also the BB torque sensor wont fit my bike. Not really an issue if this has an indepadnt throttle - thats what I use all the time anyway.

Finally - not sure what this means

"2. It only fits the motor with inner speed sensor. Please make sure your motor has inner speed sensor. It doesn't fit the external speed sensor.

"

 

[KirstinS]

Your present motor might be more powerful than a Q100H. I think it would go quite well with one of those 48v batteries with the included 20A sine wave controllers. Maybe put a couple of crimps in the shunt, which is accessible, to get the current down to 17 or 18A. You can always solder it to get it back afterwards. They come with the other stuff too, so it would be easy to swap. Torque arms as well.

Question for you D8veh having put a little more thought into it (and whilst i wait for BMS to get back to me on the sine wave/ sensorless motor point)

If I were to get a ku93 (36v version, 20a) and run 48v through it then, I think, this would have same effect as the 48v 20a battery sinewave combo ? This controller can def take sensorless

might need to cut the shunt back a little as you suggest . And the caps are 63v from my research so could even up the voltage a wee bit more As long as i'm bery careful abut the amps

 

[Deleted member 4366]

I forgot that your motor is sensorless.

"2. It only fits the motor with inner speed sensor. Please make sure your motor has inner speed sensor. It doesn't fit the external speed sensor.

Some motors have an internal speed sensor, which is basically a hall sensor and a magnet. They use the 9th middle wire in the normal 9-pin motor connectors, which is a white wire. It's no big problem for someone with your competence. You can use any speed sensor, even a 2-wire one of a cycle computer. You just have to solder or otherwise join the signal wire to the white wire inside the controller and the other to a 5v pad. If you have a three-wire sensor, you need to connect to ground as well.. Without the speed sensor, the controller will go to sleep after some minutes.

Cwah didn't mention a speed sensor in his setup, so I've asked him how it works. Maybe the Q100H has a speed sensor in it.

I'm still waiting for someone to try the Q128H, which might be a hidden diamond. The old Q128 was gutless, but if they've changed the magnets and coil wire, it could be a nice half-way house between the BPM and Q100.

The KU 93 is 36v and 48v, so no problem with that, but you have to cut back the current. 22A at 48v is a lot for a sensorless SWX type motor. Those motors make a bit of a rasping noise at 20A and 36v, so it'll be worse any higher, especially with the less accurate timing from sensorless.

 

[KirstinS]

Thanks d8veh

I veering towards a ku93 ( cutting back shunt) and 36v bottle battery (with 3s booster) to get my 48v

I'll have a look at the 128h - might be guinea pig for that one

Edit - ahh that one is rear only, no good for me as I have hub gears