Connect KT controller with USB

[amberwolf]

If it's 12-72v, it should mean that you can power it directly from your main battery (assuming that is within that range). But you should probably verify that's what they mean first.

As long as it's output signal is a standard "open collector" type, where it is floating, no voltage output, when off, and grounded when on, it would be compatible with any typical ebrake input.


Best guess for the high voltage requirement vs 5v would be if it was intended for a scooter or something that uses a 12v+ lighting system....

 

[Smurf2]

If it's 12-72v, it should mean that you can power it directly from your main battery (assuming that is within that range). But you should probably verify that's what they mean first.

It is unuseful. Because I have 5v out, not 12v out. That means that must pull new wires from the battery, which can be dangerous.
Never mind.


I mean to shorten 1T5 cable, but it looks too messy .. ?

BBSHD Wiring

Hi, I'm trying to make one cable that has the Bafang 8 pin Higo connector on one end and display and throttle on the other (I don't need brake sensors in the wiring) I've cut the 8 pin end from a 1 to 4 waterproof cable and trying to wire that into throttle and display extension cables...

endless-sphere.com

Why he cut the wires where the throttle and display are??
Wouldn't it be easier just to cut 9 wires at half, to get same from the booth side, and just connect the same colors? Is that method can be 100% safe?

 

[amberwolf]

It is unuseful. Because I have 5v out, not 12v out. That means that must pull new wires from the battery, which can be dangerous.
Never mind.

Battery voltage is present in the display-controller cable in two places. B+ and Lock (KSI, ignition, etc).

 

[fill]

I would suggest keeping at least 1 of the brake sensor lines for an emergency stop motor button/switch. Ive re-laced a motor wheel from a bike with no brake sensors, and boy that thing had been ripped apart..

 

[Smurf2]

I would suggest keeping at least 1 of the brake sensor lines for an emergency stop motor button/switch. Ive re-laced a motor wheel from a bike with no brake sensors, and boy that thing had been ripped apart..

I have. Will back to old sensor with outside magnet, which work.

 

[Smurf2]

If nobody knows answer on above question, then next question what will be exact setting for P1 and P2?

I have Rear Hub Bafang motor 500W/48v, G020.500.DC.

Maybe this are correct data.

Bafang SWX02 48V 500W RM G020.500.DC Rear Freewheel Rear Cassette Wheel gear Motor for Electric Bicycle Conversion Kit

Bafang SWX02 48V 500W RM G020.500.DC Rear Freewheel Rear Cassette Wheel gear Motor for Electric Bicycle Conversion Kit

www.pswpower.com

I know that P1 =Motor gear reduction ratio x rotor magnet (pulses) piaces.

I contacted my seller and he told me what you can see on picture.

So, P1 = 100 and P2= 6?

 

[Smurf2]

Hi again.

After I bought a new KT controller, my speed is 38 km/h.
On the old Bafang controller display shows 42 km/h.
All that on fully battery.

I know that maybe exist difference in setup, but I don't remember how much was shown in GPS. But I know that was close, maybe 1+/- km/h.

I mean one day to connect old controller, just for test with GPS, but that needs a work with connectors.

This KT display shows mostly correct with GPS. And I feel like I go little slower than Bafang.

The main question is, can I change max speed "a little" by buying with new KT controller? (like 5-10 km).

I have a 48v battery and a 500w Bafang motor. Controller in picture.

 

[fill]

My understanding is that Max rpm of a motor is more to do with voltage. Amps allow it to maintain that speed under load.. So A 22a controller for example next size up from the 17a with a 48v battery wont necessarily go significantly faster, just be able to climb steeper hills at top speed or pull a higher load.
( EDIT** what speed does the wheel hit when lifted off the ground -no load?? if faster and closer to target Yes a 22a or higher amp controller could help..) - otherwise..

the voltage to rpm relationship is proportional. that is a 10% rise in voltage should increase max rpm by 10%

so if you want a 10mph speed increase over 38mph thats about an increase of lets call it 25% ..

assuming you tested your speed and bike etc with a fully charged 48v battery at 54.6v?
A 72v battery and controller would give you that and some headroom possibly..

An other option would be to seek out a motor designed to run faster in a smaller wheel diameter such as those in commuter folding bikes. re-laced into a bigger wheel and supplied with enough amps to support it, you should get higher speeds at lower volts.

grin (ebikes.ca) have a lot of info on wheels/motors as well as a good knowledgebase and resources..

 

[Smurf2]

assuming you tested your speed and bike etc with a fully charged 48v battery at 54.6v?

Yes, I said above that I'm talking on fully charged battery.

A 72v battery and controller would give you that and some headroom possibly

I will not do big changes like battery, wheel or motor, for now.

Btw. I talking about 38 kmh, not mph

And what about 25ah or 30ah controller. That will be overkill? (if calling like that).

Also, we forget mention that a bigger ah will drain battery faster, right? But I have few km rooms to manipulate.

I'm searching for a video or topic is there someone tested different controllers, I can't find any, for now...

EDIT:
I forget a mention that China classifide aH to the motor whats, i.e. I have to low controller (17Ah) for my 500w motor. My motor need 22ah by looking down description?

15Ah - 250w
17ah - 350w
22ah - 500w
25ah - 750w
30ah - 1000w
35ah - 1500w

https://a.aliexpress.com/_EGXlbJj

 

[fill]

If you lift the drive wheel off the ground and open the throttle is the speed it hits faster than the top speed when you were riding the bike, or just about the same give or take 1-2 miles../km, er hour ?

The voltage NOT amps relate to speed/rpm so if your bike is as fast with you on it as it is with no load providing more amps with a bigger controller will have little effect.

However if your motor runs significantly faster with no load then Yes a higher rated controller will enable you to reach the same/similar speeds when under load aka ridding the bike.

 

[Smurf2]

fill said;
( EDIT** what speed does the wheel hit when lifted off the ground -no load?? if faster and closer to target Yes a 22a or higher amp controller could help..)

If you lift the drive wheel off the ground and open the throttle is the speed it hits faster than the top speed when you were riding the bike, or just about the same give or take 1-2 miles../km, er hour ?

Thank you. That is a great idea!

I tested this morning and on "empty" wheel goes 44.3 km/h on fully battery.
(On load with me goes 38 km/h).

Not had time to check controller settings. But I think that settings are on max (current). If not, I will tell you later.

So, which controller you guys think that will be closer that speed? 22Ah? What about 25Ah?

Second question, bigger controller drain battery faster, right?
Can be damage a battery?

 

[fill]

Sounds like you can benefit from a more powerful controller.

When selecting a controller just ensure the peak drain is BELOW the Maximum Drain of the battery package, if not displayed on the battery case will be a detailed in the BMS specification. and give the controller peak value some overhead for comfort too. so if your battery max drain is 25a dont get a 25a controller but a 22a will give you that comfortable overhead.

IMO Dont rely on configuration settings as systems can reboot/restart/reset, unexpectedly/inadvertently..

 

[Smurf2]

When selecting a controller just ensure the peak drain is BELOW the Maximum Drain of the battery package, if not displayed on the battery case will be a detailed in the BMS specification.

Yes, I will check that!

Futhermore, friend told me that I can modify the controller with a bit of solder iron.. And that might give you more amps.

What do you think of that?

I found video which might be that:

 

[fill]

the 'shunt mod' if relied upon for continuous power supply can stress the other components in the controller leading to overheating and its issues.. afaik best applied when that extra power is needed for short hill climbs etc..

but its sure a lot cheaper than a new controller and depending on your use may last a long time..

 

[Smurf2]

Ok. I connected the other controller, Bafang 18a, with display. The test is compared with the new KT 17a with GPS. Same time, same weather conditions. The test was repeated several times in both directions to eliminate wind.

KT 17a:
Display: 38 kmh
GPS: 39 kmh

Bafang 18a:
Display: 39 kmh
GPS: 43 kmh

So, old Bafang is little faster.