Help! Fiido D21 or Woosh Rambletta

[Woosh]

A couple of clarifications.

I thought that cadence sensors that actually used the cadence as more than an on/off pedalling/not pedalling were pretty rare.

I thought that most current control systems also included speed control, so that at half setting not only is the current halved below cutoff speed, but the speeds at which the current ramps down and cuts off are alos lowered.

Is that right?

that's correct.
I am usually rubbish at explaining things, I found this brilliant explanation on the famous Grintech's ebikes.ca:

https://ebikes.ca/learn/pedal-assist.htm

Which is Better?
This is one of those questions with an "it depends" kind of answer. Many people will assume that a torque sensor is ideal and represents the gold standard for PAS control, and that the basic PAS sensors represent a poor but inexpensive alternative. We don't think it's that simple, as people who prefer to regulate motor power independently from their pedal effort will be better served with a basic PAS setup.

A torque based control directly couples the motor power to the rider's power output. That means that going uphill you need to pedal hard to get sufficient power to climb, while on the flats or downhill’s if you pedal hard you will end up getting motor power when you don't actually need or want it. The overall experience is similar to riding a non electric bike, where your riding efforts vary significantly with the terrain; sweat going up, take it easy going down. If that is the behavior that you want then it works extremely well.

On the other hand, one of the benefits of an ebike is that you can use the motor to decouple the terrain from how hard you need to pedal. The motor can make up the difference between what your legs are putting out and what is required for the given hill and headwind. If you want to be able to ride comfortably with a given effort that doesn't change much whether going up or down, then you'll need the motor to put out lots of power when climbing, and then minimal to no power on the downhills, even while leg power remains the same. A basic PAS sensor with an easily handlebar adjustment for the PAS power level allows you to achieve this behavior quite nicely. It provides independent control of motor power and your pedal effort like a throttle, but without needing to constantly hold a throttle position.

 

[Bannerblade]

that's correct.
I am usually rubbish at explaining things, I found this brilliant explanation on the famous Grintech's ebikes.ca:

https://ebikes.ca/learn/pedal-assist.htm

OK that makes sense.
Torque sensor for power proportionate to the effort or torque you apply and cadence sensor to apply power such that you don’t notice changes in gradient ( ie effort required to pedal is more or less the same).
If that’s the theory though there are presumably different levels of success in achieving it and dependent on the controller programming as mentioned in an earlier post.
Seems like it might be a bit of a lottery buying without trying first or am I reading too much into this?

 

[Woosh]

Seems like it might be a bit of a lottery buying without trying first or am I reading too much into this?

that's true but there are other considerations like geometry, quality of the components, cost etc beside the pedal sensor. None of the shops can stock all models so you can compare every aspect.
both cadence sensor and torque sensor are successful. If you are fit and where you live is not very hilly, then torque sensor is probably better. If you have a health issue then cadence sensor is godsend. If you compare the choice to food, it's not like marmite, it's more like how you like your eggs cooked.

 

[Bonzo Banana]

I think many of the basic entry level direct drive hub motor kits like violamart have very simple logic in their controllers and were designed from the ground up to be throttle based but when they came to Europe they fitted a rudimentary cadence system which as soon as you start pedalling you get full power, quite exciting but not really that safe and a real strain on the battery with such a high discharge rate. They probably represent the crudest form of cadence system. They don't care how fast you pedal as long as they see you are pedalling. Maybe I've got the last bit wrong and there is some variation in speed for some setups perhaps fine tuning the number of magnets in the bottom bracket cadence disc but for many its a very poor implementation just so they can sell into the EU market and really those kits are purely designed for throttle use which is the norm for the majority of countries in the world.