KT Current Control versus Luishi Speed Control

Jodel

Pedelecer
Oct 9, 2020
173
140
I know that Cadence has recently made some observations regarding his favourable experience of a KT system. In the event that there may be some interest in hearing of another comparison between these two different ways of operating an ebike, here’s my subjective view having replaced the 17 Amp Luishi controller on my solo with a 15 Amp KT version.

To set my comments in context, I’m now in my late sixties, with a dodgy arthritic ankle and only a fraction of the strength and fitness I had as a young man (hence the move to an ebike) so keep that in mind when interpreting my observations. I’m around 70Kgs and still work as hard as I can, so hopefully the motor doesn’t have too much to do.

My Woosh kits (DWG22C – Luishi controller) were bought for my tandem and subsequently for a solo bike. Given my size / weight, that torquey motor is probably a bit OTT for a solo, but I wanted to keep parts commonality in the event of any repairs being required in future.

Speed control on the tandem:

I’ve done about 5,000 miles on the tandem and the motor assist has been excellent. Starting off on a tandem can be a bit of a challenge and the instant shove from the motor is a great thing to have. We use throttle to help us start off before the pedal assist chimes in after about ¼ turn of the cranks.

The programmed levels of assist correspond very roughly to 8, 11, 14.5, 15 and 15.5 mph. We normally only use Levels 1 -3 and often ride above the set speed level so that there is no assist from the motor.

Plus points:
Speed control gives full power from rest and this is very handy when constantly baulked / slowed by pedestrians / dog walkers on shared cycle paths. Cycling in slow moving stop-start type traffic is also made simpler by the instant full power shove of the motor with just a brief turn of the pedals.

There is little ‘fiddling’ needed once a given power / speed level is set as the motor just increases power as required. Gusty headwinds are compensated for without you having to do anything. Similarly, on undulating roads the motor just supplies the required power if you slow down a bit on a gradient.

Negatives:
the speed control is quite slow to react if you are oscillating just above / below a chosen speed level. Although the sheer mass of the tandem + riders tends to mask any oscillation of speed, the Luishi controller seems to have a ‘window’ of about plus or minus 1 mph before it reacts. That doesn’t sound much but it is noticeable. The KT seems to react faster and within plus or minus 0.5 mph (or less).

I have brake cut offs fitted on the tandem and without these, slow speed work would be more awkward as the motor just chimes in at full power with an off / on feeling.

Current control on the solo:

I’ve only done around 100 miles on my solo since converting it to the KT system, but the differences are quite noticeable. With current control the motor is engaged constantly regardless of the assist level until the cut off speed of 15.5 mph is reached. This gives a more ‘natural’ cycling feeling as you tend gear down for slopes rather than have the motor just ramp up the power.

Plus points:
a more natural cycling experience.

You have the opportunity to customise or tune / refine whatever you want from the controller. For example, you can set the maximum desired current delivery and the individual power levels from 0 to 5 then provide a % of that maximum power level. I believe these levels are pre-set at 0, 13%, 20%, 33% 50% and 100%. BUT it is also possible to further select how the motor reacts varying from Weaker / Normal / Stronger. These further settings really do make a difference and it makes it possible to set up the bike pretty much exactly as you’d like it.

I use Marathon Plus tyres which are great for avoiding punctures, but tend to feel ‘dead’ and like peddling through treacle. The constant supply of power to the motor masks this feeling quite significantly.

On the LCD 3 display, being able to see the wattage drawn by the motor is great. I also like being able to see the battery voltage in real time too.

Minus points:
The motor won’t ‘automatically’ compensate for a gradient, you either pedal harder, gear down or turn up the power manually. So potentially more ‘fiddling’ with the power levels or gear changing as road conditions change. Alternatively, using a burst of throttle if a sharp incline is encountered can do the trick.

In summary, I can see advantages and disadvantages to both systems. My initial thoughts were that speed control works well on a big heavy machine like a tandem. On a solo, it’s a harder call but I’m tending to favour current control for that application. I suspect current control is one of those things which you grow to like and adapt your riding style accordingly so I'll probably stick with the KT system now.

How would current control work on the tandem? Well, I’ll answer that one when my (larger) KT controller arrives and is fitted in due course…..
 
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saneagle

Esteemed Pedelecer
Oct 10, 2010
6,996
3,237
Telford
I know that Cadence has recently made some observations regarding his favourable experience of a KT system. In the event that there may be some interest in hearing of another comparison between these two different ways of operating an ebike, here’s my subjective view having replaced the 17 Amp Luishi controller on my solo with a 15 Amp KT version.

To set my comments in context, I’m now in my late sixties, with a dodgy arthritic ankle and only a fraction of the strength and fitness I had as a young man (hence the move to an ebike) so keep that in mind when interpreting my observations. I’m around 70Kgs and still work as hard as I can, so hopefully the motor doesn’t have too much to do.

My Woosh kits (DWG22C – Luishi controller) were bought for my tandem and subsequently for a solo bike. Given my size / weight, that torquey motor is probably a bit OTT for a solo, but I wanted to keep parts commonality in the event of any repairs being required in future.

Speed control on the tandem:

I’ve done about 5,000 miles on the tandem and the motor assist has been excellent. Starting off on a tandem can be a bit of a challenge and the instant shove from the motor is a great thing to have. We use throttle to help us start off before the pedal assist chimes in after about ¼ turn of the cranks.

The programmed levels of assist correspond very roughly to 8, 11, 14.5, 15 and 15.5 mph. We normally only use Levels 1 -3 and often ride above the set speed level so that there is no assist from the motor.

Plus points:
Speed control gives full power from rest and this is very handy when constantly baulked / slowed by pedestrians / dog walkers on shared cycle paths. Cycling in slow moving stop-start type traffic is also made simpler by the instant full power shove of the motor with just a brief turn of the pedals.

There is little ‘fiddling’ needed once a given power / speed level is set as the motor just increases power as required. Gusty headwinds are compensated for without you having to do anything. Similarly, on undulating roads the motor just supplies the required power if you slow down a bit on a gradient.

Negatives:
the speed control is quite slow to react if you are oscillating just above / below a chosen speed level. Although the sheer mass of the tandem + riders tends to mask any oscillation of speed, the Luishi controller seems to have a ‘window’ of about plus or minus 1 mph before it reacts. That doesn’t sound much but it is noticeable. The KT seems to react faster and within plus or minus 0.5 mph (or less).

I have brake cut offs fitted on the tandem and without these, slow speed work would be more awkward as the motor just chimes in at full power with an off / on feeling.

Current control on the solo:

I’ve only done around 100 miles on my solo since converting it to the KT system, but the differences are quite noticeable. With current control the motor is engaged constantly regardless of the assist level until the cut off speed of 15.5 mph is reached. This gives a more ‘natural’ cycling feeling as you tend gear down for slopes rather than have the motor just ramp up the power.

Plus points:
a more natural cycling experience.

You have the opportunity to customise or tune / refine whatever you want from the controller. For example, you can set the maximum desired current delivery and the individual power levels from 0 to 5 then provide a % of that maximum power level. I believe these levels are pre-set at 0, 13%, 20%, 33% 50% and 100%. BUT it is also possible to further select how the motor reacts varying from Weaker / Normal / Stronger. These further settings really do make a difference and it makes it possible to set up the bike pretty much exactly as you’d like it.

I use Marathon Plus tyres which are great for avoiding punctures, but tend to feel ‘dead’ and like peddling through treacle. The constant supply of power to the motor masks this feeling quite significantly.

On the LCD 3 display, being able to see the wattage drawn by the motor is great. I also like being able to see the battery voltage in real time too.

Minus points:
The motor won’t ‘automatically’ compensate for a gradient, you either pedal harder, gear down or turn up the power manually. So potentially more ‘fiddling’ with the power levels or gear changing as road conditions change. Alternatively, using a burst of throttle if a sharp incline is encountered can do the trick.

In summary, I can see advantages and disadvantages to both systems. My initial thoughts were that speed control works well on a big heavy machine like a tandem. On a solo, it’s a harder call but I’m tending to favour current control for that application. I suspect current control is one of those things which you grow to like and adapt your riding style accordingly so I'll probably stick with the KT system now.

How would current control work on the tandem? Well, I’ll answer that one when my (larger) KT controller arrives and is fitted in due course…..
Why didn't you fit the throttle as an instant max power over-ride for the PAS power level? You don't even need a throttle. A simple push-button switch would do it.
 

Jodel

Pedelecer
Oct 9, 2020
173
140
saneagle - sorry, should have made it clearer. I have fitted a throttle to the KT system too - as you say, the instant power boost is useful, especially for an old codger! Really like the facility of the C14 parameter to make fairly subtle changes to the power levels. I'm now interested to see how I get on with a KT on the tandem. Hopefully that might happen before the winter cold and salty roads keep me off the road.
 

Sturmey

Esteemed Pedelecer
Jan 26, 2018
648
354
68
Ireland
Why didn't you fit the throttle as an instant max power over-ride for the PAS power level? You don't even need a throttle. A simple push-button switch would do it.
I tried the push button switch throttle yesterday with a Kt controller and it works well but I needed to put a silicon diode in series to get it to work as was getting an '01 info' error when pushing the button without it.
 
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guerney

Esteemed Pedelecer
Sep 7, 2021
11,530
3,276
I tried the push button switch throttle yesterday with a Kt controller and it works well but I needed to put a silicon diode in series to get it to work as was getting an '01 info' error when pushing the button without it.
Hey that's cool. Why did the diode make your legal throttle work? For an extra layer of deception, so that your throttle switch is only enabled in the unlikely scenario where the cop ignorant of pedelec law is sitting on the saddle, perhaps you could slip a pressure switch inside the seat which connects to your throttle button?

https://www.ebay.co.uk/itm/314108721197
 
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matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,962
1,415
Hey that's cool. Why did the diode make your legal throttle work? For an extra layer of deception, so that your throttle switch is only enabled in the unlikely scenario where the cop ignorant of pedelec law is sitting on the saddle, perhaps you could slip a pressure switch inside the seat which connects to your throttle button?

https://www.ebay.co.uk/itm/314108721197
There is a standard range of voltage that is interpreted as throttle input. Something like 1V to 4V. 5V is an out of range error. Diode will drop enough voltage to look like full throttle.
 
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Sturmey

Esteemed Pedelecer
Jan 26, 2018
648
354
68
Ireland
Hey that's cool. Why did the diode make your legal throttle work? For an extra layer of deception, so that your throttle switch is only enabled in the unlikely scenario where the cop ignorant of pedelec law is sitting on the saddle, perhaps you could slip a pressure switch inside the seat which connects to your throttle button?
Wire the throttle with two light gauge tin coated solid wire straight into the female throttle connector and lightly taped in so it can be instantly pulled out with one hand in an emergency. Blank of the negative with something to avoid any mishaps when wiring/rewiring.
 
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guerney

Esteemed Pedelecer
Sep 7, 2021
11,530
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There is a standard range of voltage that is interpreted as throttle input. Something like 1V to 4V. 5V is an out of range error. Diode will drop enough voltage to look like full throttle.
Thank you for explaining that @matthewslack.


Wire the throttle with two light gauge tin coated solid wire straight into the female throttle connector and lightly taped in so it can be instantly pulled out with one hand in an emergency. Blank of the negative with something to avoid any mishaps when wiring/rewiring.
I don't have a throttle on my bike, because I doubt cops know 6kph limited throttles are legal... but armed with this new knowledge I could now connect via one of my (unused) light switches I've soldered to my ebike battery, to enable a 6kph throttle button on my BBS01B, which would do nothing when pressed by rozzers - I'd have to remember to switch that particular "light" switch off after being stopped by the fuzz. Or because all of my lights are on all the time anyway, I could connect 36V from one of the used switches to a relay to enable the throttle button, switch that off when stopped. Quite honestly, with how daft my bike looks, I'm shocked I haven't been stopped already. Perhaps small 20" wheels look too puny to be a threat to law and order. 2 Weird 2 Puny.


60820
 
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