Cycle Analyst v2 with generic controller and PAS ?


100 mW
May 25, 2015
Lyon, France
Hi all,

I bought a 2nd hand ebike which had a 24V battery (I don't remember if it was lead or lithium), some years ago. I converted it to 10s lithium a while back and it worked great but much too fast for my needs (the bike could go at 38 kph if I pedalled enough). I bought a CycleAnalyst V2 in the hope that I could limit the speed of the motor. Unfortunately, whatever the changes I made in the CA settings, they didn't do anything (whether it was Max amps or max speed). Oh, and I forgot to say I added a CA-compatible plug to my generic controller thanks to this page:

How To Add A Cycle Analyst Connector To A Controller (thank you very much to the author)

The CA sees the battery voltage and bike speed so I figure the plug works.

As I said above, the controller doesn't seem to take into account what the CA tells it to do (I think it's normal at this stage).

Since I don't want to buy a CA v3 (these beasts are quite expensive and I do want to use the CA v2 I have), I thought about disconnecting the PAS connector on the controller and fit a throttle to the CA. That would probably work (I haven't tried), but would be tedious.

So before going this route, can anyone confirm I won't be able to use the ebike PAS (cadence PAS) with my CA v2 ? Thank you very much
The most common CAv2 "CA connector" wiring is different from the CAv3. The page you link is for the usual v3 wiring.
CA v2.3 manual: Note the CA connector of this is called "throttle over-ride", not just "throttle"
1 = Vbatt (Red) 2 = Ground (Black) 3 = Shunt - (Blue) 4 = Shunt + (White) 5 = Speed (Yellow)* 6 = Throttle Over-ride (Green)

V2 works by essentially shorting the controller's throttle input signal to ground, so *if* you have a throttle on that controller, the CA would, when a limit is reached, turn the throttle "off" until the limit is no longer exceeded. The actual throttle still connects to the controller (not the CA).

The CA does not connect to the PAS input to do this function so it wouldn't be able to do any limiting if you use controller PAS and not *just* throttle. (you *might* be able to use the CA's throttle-control wire to connect *instead* to the PAS signal, with a diode on that PAS signal instead of the throttle signal

There *is* an option with the v2.3, for instance (I don't know which version you have) to use it like the v3 instead, such as in Current throttle mode, with the actual throttle only connecting to the CA and the CA's throttle signal (a separate pad on the board inside, AFAICR different from the override, the manual has a diagram) conecting to the controller's throttle input...but there is *no* PAS option in this version and you can't use the PAS on the controller. See below for how the CAv3 works, for how this mode will work.

The CAv3 works by generating an actual complete throttle signal based on your settings / limits and the actual throttle (or PAS, or both) input to it from your controls. The controls do *not* connect to the controller, *only* the CA does, to the throttle input of the controller.

The only way the CAv3 can limit anything in the controller at all is if it is creating the throttle signal that directly and solely operates the controller.

If the controller has any throttle or PAS input to it that doesn't come directly from the CA's throttle output, then the controller will do whatever it is told to do by that, instead.

Note that for either one, if your controller requires the PAS input to operate, the CA wont' be able to do it's job. Some controllers that come with a PAS simply wont' work without the correct signal from it, and when that signal is present it activates the controller, *or* it causes the controller to operate at the full output of the presently-chosen assist level. Some controllers with a PAS work perfectly normally with just a throttle input signal, and some of them work the same in any assist mode, and some require specific mode(s) to be chosen for the throttle to be available.

If you want PAS control, you'll have to use a CAv3. (vs CAv2)

If you don't want any PAS control and *only* want throttle control, the v2 will work in either of the modes above.
When you talked about the wrong wiring of CA depending on versions, I double-checked my work but everything seems good (even the 1K resistor), and at least comparing with documentation from CA V2.3, V2.4 and 3.1, all versions share the same pinout for the CA connector.
My generic controller fortunately has a throttle input, and works great with a thumb throttle I have.

I think I'll disconnect the PAS controller and use the throttle to get the bike going (+pedalling of course). It'll be enough for me since this bike is only there as a spare.

Thank you very much for your long and thorough message.
When you talked about the wrong wiring of CA depending on versions, I double-checked my work but everything seems good (even the 1K resistor), and at least comparing with documentation from CA V2.3, V2.4 and 3.1, all versions share the same pinout for the CA connector.
Yes, it is the same pinout, but the signals are not the same on all versions, depending on how the CA itself is wired inside for the 2.x versions.

The throttle signal *inside the CA* could go to one of two different places, and depending on the mode you choose (and the firmware version for which modes are available), will have different signals:

--one is just an override, which grounds out the existing throttle signal from your actual throttle that is plugged into the *controller* (not the CA),
--The other is an actual throttle signal from the CA to the controller's throttle input, and your actual throttle (or PAS) is plugged into the *CA* only, not the controller.

ThD = Throttle Over-ride output (green wire), same as ThO signal but already connected via a diode to pull down user’s throttle.
ThO = Throttle Output, use this pad for output with Current Throttle mode described in Section 9.2
Well, I finally finished the change with the bike with CA V2 and thumb throttle. The limitations (speed and current) are respected so I'm happy (some fine-tuning will be probably need to be done at some point). I almost thought I had damaged my controller when tinkering because the motor wouldn't run when the throttle was activated. It was only the brake playing up and driving me crazy ! All fixed now.

It happens that I found a CA V3.0 in my jumble (bought 2nd hand and waiting for a possible use) but stuck to my idea of using a V2 with this bike.

Thanks again Amberwolf, I've read a lot of interesting posts from you here, and will probably continue doing so next time I'm stuck in a technical problem ;)