Working to put GRIN CA3-DPS + External Shunt onto Lectric ONE

[Tom521]

As the title says I'm working to add a GRIN DPS + External Shunt onto my Lectric ONE.

Why? Because the standard Lectric speed control - tried thumb throttle first then the rotating throttle - both still act like a light switch. Can't accelerate smoothly away from a stop - just a lurch to practically wide-open throttle. Steady speed on throttle only is a joke; bike speed oscillates like a yoyo.

GRIN says that with their CA3-DPS and a Cycle Analyst molded external shunt I can have full and easy control of the throttle's behavior. It's so annoying that it's worth spending some time and money to fix it!

I have the parts in hand. I plan to put the CA3 in series with my throttle output (it's a Hall throttle BTW) and then all I need is battery voltage to the CA3 and I can try it.

I plan to retain the Lectric controller.

Presently stuck looking for battery voltage source!

I can remove and replace the Pinion drive to get battery voltage, or remove and replace the battery holder to accomplish a similar thing.

The CA3 does not need much current to operate in the throttle-only mode - only the voltage from the battery and apparently a very small current. To quote the manual: the heavy red leads are only a packaging consideration and a convenient means to pick up Vbatt+ for CA power and monitoring; they do not need to carry primary controller power.

So here's a question: is there a simpler, easier way to tap into Vbatt+ on the Lectric ONE? Maybe a used or unused plug near the handlebars?

Thank you in advance for any thoughts/ideas!

Tom

 

[RunForTheHills]

Sorry, I haven't taken apart a Lectric One. However, many/most displays have a pin going to them with battery voltage and should also have ground. You may be able to tap into that. You could test that with a multimeter.

 

[6zfshdb]

I'm not sure if Lectric uses a proprietary throttle or not, but most 3 wire Hall sensor throttles operate like this:

If you can access the throttle wiring, you may be able to insert a padding resistor in the circuit to get better throttle response. I did this successfully on my Pedego throttle.

You already have the CA3 though, so this may not be the best option.

 

[Tom521]

6zfshdb,​

Thank you! I installed the ElectricAllWheel (EAW) twist throttle to replace Lectric's thumb lever. No improvement. Interestingly it now feels exactly the same as the Lectric Trike2 750 did - no response at all for the first 10 degrees or so of twist, then hang on!

As soon as all the wiring bits arrive I will check the voltages you kindly posted - EAW told me the throttle is Hall Effect so it should work fine with the new add-in pieces from GRIN.

Probably get going next week unless the shipping delays continue.

RunForTheHills,​

Thank you again - I've ordered enough connectors to almost start a shop - when they get here I plan to follow your suggestion for a VBatt+ source by splicing into the voltage input to the present Lectric screen.

Tom

 

[RunForTheHills]

RunForTheHills,​

Thank you again - I've ordered enough connectors to almost start a shop - when they get here I plan to follow your suggestion for a VBatt+ source by splicing into the voltage input to the present Lectric screen.

Tom

I know the feeling. If you save them in a parts bin and remember you have them, it could save a future purchase.

 

[6zfshdb]

FWIW, I find a twist or thumb throttle is great for starting, especially on a hill if you forget to downshift. However, maintaining a constant speed with one of these throttles, even a properly proportioned one, can get uncomfortable after awhile. After just a few minutes, I get cramps in my thumb or wrist while trying to hold the throttle steady.

As a result, I did some experimenting and found a Hall throttle sensor can be emulated using a series of resistors. If a variable resistor (pot) is used, as in this circuit, speed can be varied, and held in position, by turning a knob. In effect, It's a form of cruise control.

Using this principle, I built a handlebar mounted "black box" speed control that can be switched on or off:

Here's a link to a thread on how it was done:

Adding a Rotary Dial Speed Control

I occasionally get a cramp in my right hand when using my half grip twist throttle. As a remedy, I built this small control box as an alternate way to adjust speed. In doing some research, I discovered a 3 wire hall effect throttle can be emulated with a variable resistor. I wired the control...

forums.electricbikereview.com

 

[Tom521]

Here's my latest message from a thread I'm not sure why I continued...

Update for the end of July (who knew this would be such a low priority???):

I have the CAV3 wired in for power so it comes on when I turn the bike on from the switch on the handlebar.

I have installed a twist throttle that is supposed to be Hall Effect.

My first attempt at wiring the throttle failed - the bike gave error code 008 - it doesn't see the throttle. It turned out to be a bad connection (strike one for the home team.)

The next attempt resulted in the bike not giving the error code (YAY!) but ignoring any throttle input (BOO!) I apparently had wired the ground connection to the CAV3 input and output (strike 2.)

Currently I have a different throttle wire connected to the CAV3 and the bike's throttle now works. Alas, it works the same as it did without the CAV3, i.e., like a light switch; the motor is either off or on - no speed modulation. This is apparently the way Lectric designed this thing...

To test this I removed the CAV3 from the circuit and the throttle response was the same - it turned the rear wheel in light-switch fashion regardless of the PAS setting from 1 to 5. PAS 1 did give a lower speed.

It's as if the CAV3 simply passed its input through to the Lectric ONE controller without tempering it.

Tomorrow I plan to try to see if the input voltage (from the throttle) measures the same as the output voltage from the CAV3. If this happens it would indicate to me that I have to learn how to program the CAV3. I'm trying to get a proportional output from the CAV3 that reflects the throttle position instead of the all-or-nothing version the Lectric controller seems to produce.

If anyone knows how to set up the CAV3 to modulate the throttle input - or even where to begin - it might be a major help!

Tom

I'll continue here because the title seems more fitting

I received more probe attachments today, so I'll try to get the proper throttle pin identification - I think I know what they are but...

 

[Tom521]

It becomes more obvious I need to learn the CAV3 throttle niceties. In re-reading the manual (OK, I'm a slow learner), the throttle default is "Pass through." This is exactly what I experienced!

Now I need to observe the voltages coming from the throttle, and then from the CAV3 output to my controller.

Once I do that there may be a way to get the CAV3 to slow down the throttle's output voltage in a way that is digestible to the controller. Or not...

One step at a time.

Tom

 

[Tom521]

Well...

Checked voltages and learned some things I didn't wish to learn. Ain't that always the way?

First, output from the throttle is from about 0.8V to 4.2V as expected.

Next, the controller runs WFO at any voltage over 1.35.

Finally a softer start can be achieved with the CAV3 by changing the Throttle Up Rate setting from 2.0V to 0.5V.

Where to from here? Think I'll go have some lunch!

Tom

PS: I wonder If I could have the CAV3 slowly sneak up to 1.35V tops? Naaah, probably wouldn't work If I could... Somehow Lectric needs to be responsible and change the controller response to the throttle!

 

[Tom521]

Does anyone know whether the Lectric controller can be programmed using the STM32 ST-LINK software?