New (real) cadence sensing controller(s) for cheap dual motor hub drive bike

[eTouringOldie]

I bought a SMLRO SMC-600 plus (2 x 1k hub drive). The PA is 'on/off' as described down in the middle of this article:

I Hate Ebike Torque-Sensing (maybe you should too)

Well, I don’t actually hate it, but it is a technology rooted in cycling’s past, whose existence was created to market a product to legacy riders.

talesontwowheels.com

I would like to change out my controllers for some which actually respond to my cadence, rather than just hitting full power (for the chosen PA level) as soon as I start pedaling.

There are two controllers -- both are 48V, 25 amps. The main controller connects to 'everything' -- rear motor, slave controller, display, battery, brakes, cadence sensor, lights, horn, etc. The other controller just connects to the front motor and the main controller.

I don't know if I'm looking for something very specific, or if there are 'generic' controllers which would work for this and other bikes. Bottom line: I don't know where to start, and of course, the manufacturer is no help.

I guess another question is -- any reason not to use a single, dual-motor controller vs the 'master & slave' setup currently on the bike?

Perhaps I should post this in a 'bike-specific' thread, but I guess I'm not the only one with this problem, and this is certainly not the only bike out there with this 'cheapest possible' set of controllers. If I do figure out the 'right' answer, I will post to a specific thread.

TIA!

 

[E-HP]

Depends on how much you want to spend and on what components to solve your PAS issue. If both controllers have a throttle input, then you may consider keeping them and putting a Cycle Analyst in front of them. The CA feeds a throttle signal to the controller, but has several throttle modes (what you are describing is called a speed throttle, where the throttle position is associated with speed, and the controller provides as much power as it can to attain that speed). A power or current throttle will apply power based on the throttle setting, and not vary the way a speed throttle does. You may ask why this matters for PAS, but PAS uses the controller's throttle mode when PAS is initiated to provide power. The PAS sensor connects directly to the CA. The CA has many settings to fine tune PAS, like adjusting the ramp up and down, start/stop of PAS assist, has various thresholds related to PAS, as well as using the actual cadence signal to adjust power (you can have the CA adjust assistance based on cadence, so if you pedal faster, you can get more (or less) assist, etc. (I use this so when I downshift for a hill, and cadence increases, I get more assist to climb without pushing any buttons, etc., so you can get creative with how you fine tune it to your riding style.

 

[amberwolf]

As E-HP says, your best bet is the Cycle analyst from ebikes.ca

Cycle Analyst V3 - Grin Products - Product Info

The Cycle Analyst display is our first flagship product released in 2006 and now in its 3rd generation. While the hardware design may be showing its age, it still has capabilities and functionalities that are unmatched by modern ebike systems with their pretty colour screens. This device also...

ebikes.ca

I use it to send a throttle signal to both controllers (one for each rear wheel on SB Cruiser) that it creates based on my cadence from a PAS sensor, processed via the settings I chose in it's menus.

It's a bit complex to setup, but works perfectly once this is done.


The only thing your existing system has to do is be able to run without it's PAS sensor attached (because this will now go to the CA instead), and run exclusively from a throttle signal. If you already have a throttle, you can verify this will work by disconnecting the PAS sensor and using just the throttle in the highest power assist mode. If it works, then you can use the CA to generate that throttle signal from your PAS sensor.

If it doesn't, you can replace the two existingg controllers with any two "dumb" controllers that can provide the necessary power and operate only from a throttle, and have the CA provide that from your PAS sensor.

"dumb" contorllers are those without a display or settings of their own, that just do what they're told via the throttle input, and are always in "full power mode", meaning eveyrthing they have is always available to you. (some do have a "three speed switch" that offers a limit to their power or speed, but doesn't have to be used).





FWIW, pretty much all the non-torque-sensor-based controler systems are going to use a "cadence" PAS sensor exactly like yours does now--full amount of whatever assist level you select, or no assist at all-not actually caring how fast or hard you are pedalling. If you can find one that doesn't, we'd appreciate knowing about it. So far the only ones that existed don't seem to be made anymore, which is pretty weird, since it is a much better control mode than the on/off type used in all of them presently.


There *are* controllers that operate via torque sensors, and THOSE do actually provide proportional assist..but not to the cadence, only to the force on the pedals.

The CA can actually do both at the same time (or rather, respond as needed to either sensor depending on the situation and settings), and make a throttle signal that tells the dumb controllers what to do.